├── tests
    ├── arginc.c
    ├── cond.c
    ├── inc.c
    ├── while.c
    ├── read.c
    ├── fib.c
    ├── swap.s
    ├── eq.c
    └── x86.s
├── hello.c
├── README.md
├── dlfcn32.h
├── mman32.h
├── JIT.md
├── LICENSE
├── c4.c
└── c4x86.c


/tests/arginc.c:
--------------------------------------------------------------------------------
1 | int main(int argc, char **argv) {
2 |     return argc + 1;
3 | }
4 | 


--------------------------------------------------------------------------------
/hello.c:
--------------------------------------------------------------------------------
1 | #include <stdio.h>
2 | 
3 | int main()
4 | {
5 |   printf("hello, world\n");
6 |   return 0;
7 | }
8 | 


--------------------------------------------------------------------------------
/tests/cond.c:
--------------------------------------------------------------------------------
1 | int main(int argc, char **argv) {
2 |     if (argc == 1) { printf("Usage: <me> <gibberish>\n"); }
3 |     else { printf("argc = %d\n", argc); }
4 |     return 0;
5 | }
6 | 


--------------------------------------------------------------------------------
/tests/inc.c:
--------------------------------------------------------------------------------
 1 | int inc(int x) {
 2 |     return x + 1;
 3 | }
 4 | 
 5 | int add2(int x) {
 6 |     return inc(inc(x));
 7 | }
 8 | 
 9 | int main(int argc, char **argv) {
10 |     return add2(argc);
11 | }
12 | 
13 | 


--------------------------------------------------------------------------------
/tests/while.c:
--------------------------------------------------------------------------------
 1 | #include <stdio.h>
 2 | 
 3 | int fact(int n) {
 4 |     int r;
 5 |     r = 1;
 6 |     while (n > 0) {
 7 |         r = r * n;
 8 |         printf("n = %d, r = %d\n", n, r);
 9 |         --n;
10 |     }
11 |     return r;
12 | }
13 | 
14 | int main(int argc, char **argv) {
15 |     printf("%d\n", fact(8));
16 |     return 0;
17 | }
18 | 


--------------------------------------------------------------------------------
/README.md:
--------------------------------------------------------------------------------
 1 | c4 - C in four functions
 2 | ========================
 3 | 
 4 | An exercise in minimalism.
 5 | 
 6 | Try the following:
 7 | 
 8 |     gcc -o c4 c4.c  (you may need the -m32 option on 64bit machines)
 9 |     ./c4 hello.c
10 |     ./c4 -s hello.c
11 |     
12 |     ./c4 c4.c hello.c
13 |     ./c4 c4.c c4.c hello.c
14 | 
15 | 
16 | c4x86 - JIT compiler for x86 in 86 lines
17 | ========================================
18 | 
19 | An exercise in bit-twiddling masochism.
20 | 
21 | x86 only, not self-hosted!
22 | 
23 |     gcc -m32 c4x86.c -o c4x86
24 |     ./c4x86 hello.c
25 |     ./c4x86 c4.c hello.c
26 | 


--------------------------------------------------------------------------------
/tests/read.c:
--------------------------------------------------------------------------------
 1 | #include <stdio.h>
 2 | #include <stdlib.h>
 3 | 
 4 | int main(int argc, char **argv) {
 5 |     char *p;
 6 |     int fd, readsz;
 7 |     ++argv;
 8 | 
 9 |     if (!(p = malloc(1024 * 16))) { printf("failed to malloc memory\n"); exit(1); }
10 | 
11 |     printf("opening %s...\n", *argv);
12 |     fd = open(*argv, 0);
13 |     //if (fd < 0) { printf("failed to open %s\n", *argv); exit(2); }
14 | 
15 |     readsz = read(fd, p, 1024 * 16);
16 |     printf("read %d bytes\nContents:\n______________________________\n%s", readsz, p);
17 |     printf("\n_______________________________\n");
18 | 
19 |     exit(0);
20 | }
21 | 


--------------------------------------------------------------------------------
/tests/fib.c:
--------------------------------------------------------------------------------
 1 | #include <stdio.h>
 2 | #include <stdlib.h>
 3 | 
 4 | int my_atoi(char *s) {
 5 |     int res;
 6 |     res = 0;
 7 |     while (*s) {
 8 |         if (*s < '0' || '9' < *s) 
 9 |             return 0;
10 |         res = res * 10 + (*s - '0');
11 |         ++s;
12 |     }
13 |     return res;
14 | }
15 | 
16 | int fib(int n) {
17 |     if (n < 2) return 1;
18 |     return fib(n - 1) + fib(n - 2);
19 | }
20 | 
21 | int main(int argc, char **argv) {
22 |     int n;
23 |     if (argc < 2) { printf("Usage: %s <number>\n", argv[0]); exit(1); }
24 | 
25 |     n = my_atoi(argv[1]);
26 |     printf("%d\n", fib(n));
27 |     return 0;
28 | }
29 | 


--------------------------------------------------------------------------------
/tests/swap.s:
--------------------------------------------------------------------------------
 1 | argc1:
 2 |     pop %ecx
 3 |     mov %esp, %esi
 4 |     andl $0xfffffff0, %esi
 5 |     mov %ecx, (%esi)
 6 |     xchg %esi, %esp
 7 | 
 8 |     call 0xdeadbeef
 9 |     xchg %esi, %esp
10 | 
11 | argc2:
12 |     pop %ecx
13 |     pop %edx
14 |     movl %esp, %esi
15 |     andl $0xfffffff0, %esi
16 |     mov %edx, (%esi)
17 |     mov %ecx, 4(%esi)
18 |     xchg %esi, %esp
19 | 
20 |     call 0xdeadbeef
21 | 
22 |     xchg %esi, %esp
23 | 
24 | argN:   # n = 4
25 |     mov $0x10, %ecx
26 |     mov %esp, %esi
27 |     subl %ecx, %esi
28 |     shr $2, %ecx
29 |     andl $0xfffffff0, %esi
30 |     
31 | 1:
32 |     pop %edx
33 |     mov %edx, -4(%esi, %ecx, 4) # -4 to compensate %ecx off-by-one
34 |     loop 1b
35 |     
36 |     xchg %esi, %esp
37 | 
38 |     call 0xdeadbeef
39 |     
40 |     xchg %esi, %esp
41 | 


--------------------------------------------------------------------------------
/dlfcn32.h:
--------------------------------------------------------------------------------
 1 | #ifdef _WIN32
 2 | #include <io.h>
 3 | #include <stdlib.h>
 4 | #include <string.h>
 5 | #include "mman32.h"
 6 | enum {
 7 | 	RTLD_LAZY = 1,
 8 | 	RTLD_GLOBAL = 2
 9 | };
10 | int dlopen(int x, int y)
11 | {
12 |   return 0;
13 | }
14 | void *dlsym(void *handle, char *name)
15 | {
16 |   if (!strcmp(name, "open"  )) return &open;
17 |   if (!strcmp(name, "read"  )) return &read;
18 |   if (!strcmp(name, "close" )) return &close;
19 |   if (!strcmp(name, "printf")) return &printf;
20 |   if (!strcmp(name, "malloc")) return &malloc;
21 |   if (!strcmp(name, "memset")) return &memset;
22 |   if (!strcmp(name, "memcmp")) return &memcmp;
23 |   if (!strcmp(name, "memcpy")) return &memcpy;
24 |   if (!strcmp(name, "mmap"  )) return &mmap;
25 |   if (!strcmp(name, "dlsym" )) return &dlsym;
26 |   if (!strcmp(name, "qsort" )) return &qsort;
27 |   if (!strcmp(name, "exit"  )) return &exit;
28 |   return 0;
29 | }
30 | #else
31 | #include <dlfcn.h>
32 | #endif
33 | 


--------------------------------------------------------------------------------
/tests/eq.c:
--------------------------------------------------------------------------------
 1 | int main() {
 2 |     printf("16000 == 16000 : %d\n", 16000 == 16000);
 3 |     printf("16000 == 17000 : %d\n", 16000 == 17000);
 4 |     printf("2 == 2         : %d\n", 2 == 2);
 5 |     printf("0 == 0         : %d\n", 0 == 0);
 6 |     printf("-1 == -1       : %d\n", -1 == -1);
 7 |     printf("\n");
 8 | 
 9 |     printf("16000 != 16000 : %d\n", 16000 != 16000);
10 |     printf("16000 != 17000 : %d\n", 16000 != 17000);
11 |     printf("2 != 2         : %d\n", 2 != 2);
12 |     printf("0 != 0         : %d\n", 0 != 0);
13 |     printf("-1 != -1       : %d\n", -1 != -1);
14 |     printf("\n");
15 | 
16 |     printf("17000 > 16000  : %d\n", 17000 > 16000);
17 |     printf("17000 > 17000  : %d\n", 17000 > 17000);
18 |     printf("16000 > 17000  : %d\n", 16000 > 17000);
19 |     printf("16000 > -17000 : %d\n", 16000 > -17000);
20 |     printf("-16000 > -17000 : %d\n", -16000 > -17000);
21 |     printf("\n");
22 | 
23 |     printf("17000 >= 16000  : %d\n", 17000 >= 16000);
24 |     printf("17000 >= 17000  : %d\n", 17000 >= 17000);
25 |     printf("16000 >= 17000  : %d\n", 16000 >= 17000);
26 |     printf("16000 >= -17000 : %d\n", 16000 >= -17000);
27 |     printf("-16000 >= -17000 : %d\n", -16000 >= -17000);
28 |     printf("\n");
29 | 
30 |     return 0;
31 | }
32 | 


--------------------------------------------------------------------------------
/tests/x86.s:
--------------------------------------------------------------------------------
 1 | ENT: # 2
 2 |     push %ebp  
 3 |     mov %esp, %ebp
 4 |     subl $8, %esp
 5 | 
 6 | BZ: #0xdeadbeef
 7 |     test %eax, %eax 
 8 |     jz .exit
 9 |     # BNZ 0xdeadbeef
10 |     test %eax, %eax 
11 |     jnz .exit
12 | 
13 |     jnz 0x0
14 |     jz .exit
15 |     jz 0x0
16 | 
17 |     leal (-4 * 1)(%ebp), %eax    # LEA -1
18 |     movl $42, %eax          # IMM 42
19 |     jmp 0x210         # JMP 0xdeadbeef
20 |     call *0xdeadbeef        # JSR 0xdeadbeef
21 |     addl $(4 * 5), %esp     # ADJ 5
22 |     movl (%eax), %eax       # LI
23 |     movzb (%eax), %eax      # LC
24 |     
25 | SI:
26 |     pop %ecx
27 |     movl %eax, (%ecx)
28 | 
29 | SC:
30 |     pop %ecx
31 |     movb %al, (%ecx)
32 | 
33 |     push %eax
34 | 
35 | signextend:
36 |     cbw
37 |     cwde
38 | 
39 | GT1:
40 |     mov %eax, %edx
41 |     #push %eax pop %edx
42 |     pop %ecx
43 |     xor %eax, %eax
44 |     cmp %edx, %ecx
45 |     setg %al
46 | 
47 | GT2:
48 |     pop  %ecx
49 |     cmp %eax, %ecx
50 |     setg %al
51 |     cbw
52 |     cwde
53 | 
54 | EQ1:
55 |     pop %ecx
56 |     cmp %eax, %ecx
57 |     sete %al
58 |     cbw
59 |     cwde
60 | 
61 | cmps:
62 |     setl %al
63 |     setge %al
64 |     setle %al
65 |     setne %al
66 | 
67 | MOD:
68 |     pop %ecx
69 |     xchg %ecx, %eax
70 |     xor %edx, %edx
71 |     idiv %ecx
72 |     xchg %edx, %eax
73 | 
74 | .exit:
75 |     mov %ebp, %esp
76 |     pop %ebp
77 |     ret
78 | 
79 |     pop %ecx
80 |     orl %ecx, %eax
81 |     xchg %ecx, %eax
82 |     xorl %ecx, %eax
83 |     andl %ecx, %eax
84 |     test %ecx, %eax     # EQ
85 |     shll %cl, %eax
86 |     shrl %cl, %eax
87 |     add %ecx, %eax
88 |     subl %ecx, %eax
89 |     imul %ecx, %eax
90 |     idiv %ecx, %eax
91 |     
92 |     
93 | 


--------------------------------------------------------------------------------
/mman32.h:
--------------------------------------------------------------------------------
  1 | #ifndef PORTABLE_MMAP_H
  2 | #define PORTABLE_MMAP_H
  3 | 
  4 | #ifdef _WIN32
  5 | /* mmap() replacement for Windows
  6 |  *
  7 |  * Author: Mike Frysinger <vapier@gentoo.org>
  8 |  * Placed into the public domain
  9 |  */
 10 | 
 11 | /* References:
 12 |  * CreateFileMapping: http://msdn.microsoft.com/en-us/library/aa366537(VS.85).aspx
 13 |  * CloseHandle:       http://msdn.microsoft.com/en-us/library/ms724211(VS.85).aspx
 14 |  * MapViewOfFile:     http://msdn.microsoft.com/en-us/library/aa366761(VS.85).aspx
 15 |  * UnmapViewOfFile:   http://msdn.microsoft.com/en-us/library/aa366882(VS.85).aspx
 16 |  */
 17 | 
 18 | #include <io.h>
 19 | #include <windows.h>
 20 | #include <sys/types.h>
 21 | 
 22 | #define PROT_READ     0x1
 23 | #define PROT_WRITE    0x2
 24 | /* This flag is only available in WinXP+ */
 25 | #ifdef FILE_MAP_EXECUTE
 26 | #define PROT_EXEC     0x4
 27 | #else
 28 | #define PROT_EXEC        0x0
 29 | #define FILE_MAP_EXECUTE 0
 30 | #endif
 31 | 
 32 | #define MAP_SHARED    0x01
 33 | #define MAP_PRIVATE   0x02
 34 | #define MAP_ANONYMOUS 0x20
 35 | #define MAP_ANON      MAP_ANONYMOUS
 36 | #define MAP_FAILED    ((void *) -1)
 37 | 
 38 | #ifdef __USE_FILE_OFFSET64
 39 | # define DWORD_HI(x) (x >> 32)
 40 | # define DWORD_LO(x) ((x) & 0xffffffff)
 41 | #else
 42 | # define DWORD_HI(x) (0)
 43 | # define DWORD_LO(x) (x)
 44 | #endif
 45 | 
 46 | static void *mmap(void *start, size_t length, int prot, int flags, int fd, off_t offset)
 47 | {
 48 |     if (prot & ~(PROT_READ | PROT_WRITE | PROT_EXEC))
 49 |         return MAP_FAILED;
 50 |     if (fd == -1) {
 51 |         if (!(flags & MAP_ANON) || offset)
 52 |             return MAP_FAILED;
 53 |     } else if (flags & MAP_ANON)
 54 |         return MAP_FAILED;
 55 | 
 56 |     DWORD flProtect;
 57 |     if (prot & PROT_WRITE) {
 58 |         if (prot & PROT_EXEC)
 59 |             flProtect = PAGE_EXECUTE_READWRITE;
 60 |         else
 61 |             flProtect = PAGE_READWRITE;
 62 |     } else if (prot & PROT_EXEC) {
 63 |         if (prot & PROT_READ)
 64 |             flProtect = PAGE_EXECUTE_READ;
 65 |         else if (prot & PROT_EXEC)
 66 |             flProtect = PAGE_EXECUTE;
 67 |     } else
 68 |         flProtect = PAGE_READONLY;
 69 | 
 70 |     off_t end = length + offset;
 71 |     HANDLE mmap_fd, h;
 72 |     if (fd == -1)
 73 |         mmap_fd = INVALID_HANDLE_VALUE;
 74 |     else
 75 |         mmap_fd = (HANDLE)_get_osfhandle(fd);
 76 |     h = CreateFileMapping(mmap_fd, NULL, flProtect, DWORD_HI(end), DWORD_LO(end), NULL);
 77 |     if (h == NULL)
 78 |         return MAP_FAILED;
 79 | 
 80 |     DWORD dwDesiredAccess;
 81 |     if (prot & PROT_WRITE)
 82 |         dwDesiredAccess = FILE_MAP_WRITE;
 83 |     else
 84 |         dwDesiredAccess = FILE_MAP_READ;
 85 |     if (prot & PROT_EXEC)
 86 |         dwDesiredAccess |= FILE_MAP_EXECUTE;
 87 |     if (flags & MAP_PRIVATE)
 88 |         dwDesiredAccess |= FILE_MAP_COPY;
 89 |     void *ret = MapViewOfFile(h, dwDesiredAccess, DWORD_HI(offset), DWORD_LO(offset), length);
 90 |     if (ret == NULL) {
 91 |         CloseHandle(h);
 92 |         ret = MAP_FAILED;
 93 |     }
 94 |     return ret;
 95 | }
 96 | 
 97 | static void munmap(void *addr, size_t length)
 98 | {
 99 |     UnmapViewOfFile(addr);
100 |     /* ruh-ro, we leaked handle from CreateFileMapping() ... */
101 | }
102 | 
103 | #undef DWORD_HI
104 | #undef DWORD_LO
105 |  
106 | #else
107 | #  include <sys/mman.h>
108 | #endif
109 | 
110 | #endif
111 | 


--------------------------------------------------------------------------------
/JIT.md:
--------------------------------------------------------------------------------
  1 | What is it?
  2 | =============
  3 | 
  4 | `c4x86.c` is a primitive x86 Just-In-Time compiler for awesome c4 virtual machine. It took about 86 lines of C code.
  5 | 
  6 | It is known to work on Linux (and OS X?).
  7 | 
  8 | How JIT works
  9 | =============
 10 | 
 11 | JIT compilation is based on the fact that mapping c4 opcodes into x86 instructions is quite straightforward:
 12 | 
 13 | | c4 opcode    | x86 instructions                           | comments
 14 | |--------------|--------------------------------------------|-----------------------
 15 | | `IMM` *val*  |`movl $val, %eax`                           |
 16 | | `PSH`        |`push %eax`                                 |
 17 | | `LEV`        |`movl %ebp, %esp; pop %esp; ret`            |
 18 | | `ADJ` *val*  |`subl $(4 * val), %esp)`                    |
 19 | | `LI`         |`movl (%eax), %eax`                         |
 20 | | `LC`         |`movzbl (%eax), %eax`                       |
 21 | | `SI`         |`pop %ecx; movl %eax, (%ecx)`               | `%ecx` is used as a temporary register
 22 | | `SC`         |`pop %ecx; movb %al, (%ecx)`                |
 23 | | `OR`         |`pop %ecx; orl %ecx, %eax`                  |
 24 | | `XOR`        |`pop %ecx; xorl %ecx, %eax`                 |
 25 | | `AND`        |`pop %ecx; andl %ecx, %eax`                 |
 26 | | `NE`         |see `Comparisons`                           | using `setne %al` opcode
 27 | | `EQ`         |see `Comparisons`                           | using `sete %al` opcode
 28 | | `GE`         |see `Comparisons`                           | using `setge %al` opcode
 29 | | `LE`         |see `Comparisons`                           | using `setle %al` opcode
 30 | | `GT`         |see `Comparisons`                           | using `setg %al` opcode
 31 | | `LT`         |see `Comparisons`                           | using `setl %al` opcode
 32 | | `SHL`        |`pop %ecx; xchg %eax, %ecx; shl %cl, %eax`  | `xchg` adjusts the operands order
 33 | | `SHR`        |`pop %ecx; xchg %eax, %ecx; shr %cl, %eax`  |
 34 | | `ADD`        |`pop %ecx; addl %ecx, %eax`                 |
 35 | | `SUB`        |`pop %ecx; xchg %eax, %ecx; subl %ecx, %eax`|
 36 | | `MUL`        |`pop %ecx; imul %ecx, %eax`                 |
 37 | | `DIV`        |`pop %ecx; xchg %eax, %ecx; idiv %ecx, %eax`|
 38 | | `MOD`        |`pop %ecx; xchg %ecx, %eax; xor %edx, %edx; idiv %ecx; xchg %edx, %eax` | `%edx` holds remainder after `idiv`
 39 | | `JMP`        |`jmp <off32>`                               |
 40 | | `JSR`        |`call <off32>`                              |
 41 | | `BZ`         |`jz <off32>`                                |
 42 | | `BNZ`        |`jnz <off32>`                               |
 43 | | `OPEN`; `ADJ <n>`  | see `Native calls` section           | 
 44 | | `READ` ; `ADJ <n>` | see `Native calls` section           |
 45 | | `CLOS` ; `ADJ <n>` | see `Native calls` section           |
 46 | | `PRTF` ; `ADJ <n>` | see `Native calls` section           |
 47 | | `MALC` ; `ADJ <n>` | see `Native calls` section           |
 48 | | `MSET` ; `ADJ <n>` | see `Native calls` section           |
 49 | | `MCMP` ; `ADJ <n>` | see `Native calls` section           |
 50 | | `EXIT` ; `ADJ <n>` | see `Native calls` section           |
 51 | 
 52 | Some executable and writable memory is allocated with `mmap()`, its address in `jitmem` pointer.
 53 | 
 54 | First pass of the JIT compiler translates c4 opcodes into instructions directly, leaving stubs for relative offsets in `JSR`, `JMP` (4 byte offset), `BZ`, `BNZ` (1 byte offset) to be filled during the second pass.
 55 | 
 56 | Comparisons
 57 | ===========
 58 | 
 59 | Comparison uses `set<cc>` x86 operations after `cmp %ecx, %eax` where `%ecx` is popped from the stack with ensuing sign-extension of `%al` to `%eax`.
 60 | 
 61 | So, the full comparison code for, e.g. `EQ` is:
 62 | 
 63 |     pop %ecx
 64 |     cmp %ecx, %eax
 65 |     sete %al            # set %al to 0/1 depending on equality
 66 |     cbw                 # %al to %ax sign extension
 67 |     cwde                # %ax to %eax sign extension
 68 | 
 69 | 
 70 | Filling up relative offsets
 71 | ===========================
 72 | 
 73 | For addresses of compiled "labels" to be known, the first pass stores addresses of compiled x86 code for each c4 opcode in the opcode cell (of `text[]` array) itself:
 74 | 
 75 |     before:    | <opcode> | 0x00    | 0x00   | 0x00    |
 76 |     after:     | <opcode> | <least 3 bytes of x86 ptr> |
 77 | 
 78 | The most significant byte is restored from `jitmem` value (it is assumed that the native code does not take more than 24 megabytes, so the most significant byte is the same for all pointers).
 79 | 
 80 | `JMP`/`JSR`/`BNZ`/`BZ` arguments are not modified.
 81 | 
 82 | The second pass reads c4 pointers of `JMP`/`JSR`/`BNZ`/`BZ` and extracts native codes addresses. Then relative offsets are calculated to fill offset gaps in native code.
 83 | 
 84 | Native calls
 85 | ============
 86 | Native calls are tricky for x86: 
 87 | 
 88 | 1. order of arguments is reversed; 
 89 | 2. OS X ABI requires stack to be aligned at 16 bytes before calls.
 90 | 
 91 | Fortunately, arguments count is known for each call, it can be retrieved from `ADJ` right after c4 opcode of the call.
 92 | 
 93 | Both these complications require a quite hacky solution: the arguments evaluation code is left as is, but some additional stack memory is allocated before native calls (aligned to 16 bytes), arguments are copied there in reverse order and "old" stack pointer (without arguments) is saved in `%esi` register. On return from the native routine `%esp` is restored from `%esi`.
 94 | 
 95 |         movl $(4 * n), %ecx       # store 4 * #args in %ecx
 96 |         mov %esp, %esi            # %esi temporarily holds the native call stack pointer (to become %esp later)
 97 |         sub %ecx, %esi            # %esp - %esi must be large enough to contain all arguments
 98 |         andl $0xfffffff0, %esi    # the future %esp must be aligned at 16 bytes
 99 |         shr $2, %ecx              # let %ecx be just #args now
100 | 
101 |     1:                            # this is a loop copying %ecx arguments:
102 |         pop %edx                  # movl (%esp), %edx; addl $4, %esp; - %esp grows until all arguments are below
103 |         mov %edx, -4(%esi,%ecx,4) # %edx value is now stored at %esi+4*%ecx; -4 to compensate %ecx off-by-one
104 |         loop 1b                   # dec %ecx; while %ecx is not 0, return to 1:
105 | 
106 |         xchg %esi, %esp           # now %esi contains the 'old' stack pointer, %esp is adjusted properly
107 |         call printf               # %esi must be preserved according to cdecl calling convention
108 | 
109 |         xchg %esi, %esp           # ADJust: restore the stack state before the call
110 | 
111 | This is a lengthy and costly solution, but it keeps code size small.
112 | 
113 | 
114 | Issues
115 | ======
116 | 
117 | 1. this is x86 only; requires Unix-like calls; not self-hosted;
118 | 2. uses registers `%eax`, `%ecx`, `%ebp`, `%esp` only with quite redundant memory loads/stores; no register allocation;
119 | 3. it is limited to `open`/`read`/`close`/`printf`/`malloc`/`memset`/`memcmp`/`exit` calls.
120 | 
121 | 
122 | (c) Dmytro Sirenko, 2014
123 | 


--------------------------------------------------------------------------------
/LICENSE:
--------------------------------------------------------------------------------
  1 | GNU GENERAL PUBLIC LICENSE
  2 |                        Version 2, June 1991
  3 | 
  4 |  Copyright (C) 1989, 1991 Free Software Foundation, Inc., <http://fsf.org/>
  5 |  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  6 |  Everyone is permitted to copy and distribute verbatim copies
  7 |  of this license document, but changing it is not allowed.
  8 | 
  9 |                             Preamble
 10 | 
 11 |   The licenses for most software are designed to take away your
 12 | freedom to share and change it.  By contrast, the GNU General Public
 13 | License is intended to guarantee your freedom to share and change free
 14 | software--to make sure the software is free for all its users.  This
 15 | General Public License applies to most of the Free Software
 16 | Foundation's software and to any other program whose authors commit to
 17 | using it.  (Some other Free Software Foundation software is covered by
 18 | the GNU Lesser General Public License instead.)  You can apply it to
 19 | your programs, too.
 20 | 
 21 |   When we speak of free software, we are referring to freedom, not
 22 | price.  Our General Public Licenses are designed to make sure that you
 23 | have the freedom to distribute copies of free software (and charge for
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 25 | if you want it, that you can change the software or use pieces of it
 26 | in new free programs; and that you know you can do these things.
 27 | 
 28 |   To protect your rights, we need to make restrictions that forbid
 29 | anyone to deny you these rights or to ask you to surrender the rights.
 30 | These restrictions translate to certain responsibilities for you if you
 31 | distribute copies of the software, or if you modify it.
 32 | 
 33 |   For example, if you distribute copies of such a program, whether
 34 | gratis or for a fee, you must give the recipients all the rights that
 35 | you have.  You must make sure that they, too, receive or can get the
 36 | source code.  And you must show them these terms so they know their
 37 | rights.
 38 | 
 39 |   We protect your rights with two steps: (1) copyright the software, and
 40 | (2) offer you this license which gives you legal permission to copy,
 41 | distribute and/or modify the software.
 42 | 
 43 |   Also, for each author's protection and ours, we want to make certain
 44 | that everyone understands that there is no warranty for this free
 45 | software.  If the software is modified by someone else and passed on, we
 46 | want its recipients to know that what they have is not the original, so
 47 | that any problems introduced by others will not reflect on the original
 48 | authors' reputations.
 49 | 
 50 |   Finally, any free program is threatened constantly by software
 51 | patents.  We wish to avoid the danger that redistributors of a free
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 53 | program proprietary.  To prevent this, we have made it clear that any
 54 | patent must be licensed for everyone's free use or not licensed at all.
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 56 |   The precise terms and conditions for copying, distribution and
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 58 | 
 59 |                     GNU GENERAL PUBLIC LICENSE
 60 |    TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
 61 | 
 62 |   0. This License applies to any program or other work which contains
 63 | a notice placed by the copyright holder saying it may be distributed
 64 | under the terms of this General Public License.  The "Program", below,
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 66 | means either the Program or any derivative work under copyright law:
 67 | that is to say, a work containing the Program or a portion of it,
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 69 | language.  (Hereinafter, translation is included without limitation in
 70 | the term "modification".)  Each licensee is addressed as "you".
 71 | 
 72 | Activities other than copying, distribution and modification are not
 73 | covered by this License; they are outside its scope.  The act of
 74 | running the Program is not restricted, and the output from the Program
 75 | is covered only if its contents constitute a work based on the
 76 | Program (independent of having been made by running the Program).
 77 | Whether that is true depends on what the Program does.
 78 | 
 79 |   1. You may copy and distribute verbatim copies of the Program's
 80 | source code as you receive it, in any medium, provided that you
 81 | conspicuously and appropriately publish on each copy an appropriate
 82 | copyright notice and disclaimer of warranty; keep intact all the
 83 | notices that refer to this License and to the absence of any warranty;
 84 | and give any other recipients of the Program a copy of this License
 85 | along with the Program.
 86 | 
 87 | You may charge a fee for the physical act of transferring a copy, and
 88 | you may at your option offer warranty protection in exchange for a fee.
 89 | 
 90 |   2. You may modify your copy or copies of the Program or any portion
 91 | of it, thus forming a work based on the Program, and copy and
 92 | distribute such modifications or work under the terms of Section 1
 93 | above, provided that you also meet all of these conditions:
 94 | 
 95 |     a) You must cause the modified files to carry prominent notices
 96 |     stating that you changed the files and the date of any change.
 97 | 
 98 |     b) You must cause any work that you distribute or publish, that in
 99 |     whole or in part contains or is derived from the Program or any
100 |     part thereof, to be licensed as a whole at no charge to all third
101 |     parties under the terms of this License.
102 | 
103 |     c) If the modified program normally reads commands interactively
104 |     when run, you must cause it, when started running for such
105 |     interactive use in the most ordinary way, to print or display an
106 |     announcement including an appropriate copyright notice and a
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108 |     a warranty) and that users may redistribute the program under
109 |     these conditions, and telling the user how to view a copy of this
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111 |     does not normally print such an announcement, your work based on
112 |     the Program is not required to print an announcement.)
113 | 
114 | These requirements apply to the modified work as a whole.  If
115 | identifiable sections of that work are not derived from the Program,
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118 | sections when you distribute them as separate works.  But when you
119 | distribute the same sections as part of a whole which is a work based
120 | on the Program, the distribution of the whole must be on the terms of
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123 | 
124 | Thus, it is not the intent of this section to claim rights or contest
125 | your rights to work written entirely by you; rather, the intent is to
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127 | collective works based on the Program.
128 | 
129 | In addition, mere aggregation of another work not based on the Program
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131 | a storage or distribution medium does not bring the other work under
132 | the scope of this License.
133 | 
134 |   3. You may copy and distribute the Program (or a work based on it,
135 | under Section 2) in object code or executable form under the terms of
136 | Sections 1 and 2 above provided that you also do one of the following:
137 | 
138 |     a) Accompany it with the complete corresponding machine-readable
139 |     source code, which must be distributed under the terms of Sections
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141 | 
142 |     b) Accompany it with a written offer, valid for at least three
143 |     years, to give any third party, for a charge no more than your
144 |     cost of physically performing source distribution, a complete
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148 | 
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171 | 
172 |   4. You may not copy, modify, sublicense, or distribute the Program
173 | except as expressly provided under this License.  Any attempt
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175 | void, and will automatically terminate your rights under this License.
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177 | this License will not have their licenses terminated so long as such
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179 | 
180 |   5. You are not required to accept this License, since you have not
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182 | distribute the Program or its derivative works.  These actions are
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184 | modifying or distributing the Program (or any work based on the
185 | Program), you indicate your acceptance of this License to do so, and
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187 | the Program or works based on it.
188 | 
189 |   6. Each time you redistribute the Program (or any work based on the
190 | Program), the recipient automatically receives a license from the
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192 | these terms and conditions.  You may not impose any further
193 | restrictions on the recipients' exercise of the rights granted herein.
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197 |   7. If, as a consequence of a court judgment or allegation of patent
198 | infringement or for any other reason (not limited to patent issues),
199 | conditions are imposed on you (whether by court order, agreement or
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204 | may not distribute the Program at all.  For example, if a patent
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206 | all those who receive copies directly or indirectly through you, then
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209 | 
210 | If any portion of this section is held invalid or unenforceable under
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214 | 
215 | It is not the purpose of this section to induce you to infringe any
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223 | to distribute software through any other system and a licensee cannot
224 | impose that choice.
225 | 
226 | This section is intended to make thoroughly clear what is believed to
227 | be a consequence of the rest of this License.
228 | 
229 |   8. If the distribution and/or use of the Program is restricted in
230 | certain countries either by patents or by copyrighted interfaces, the
231 | original copyright holder who places the Program under this License
232 | may add an explicit geographical distribution limitation excluding
233 | those countries, so that distribution is permitted only in or among
234 | countries not thus excluded.  In such case, this License incorporates
235 | the limitation as if written in the body of this License.
236 | 
237 |   9. The Free Software Foundation may publish revised and/or new versions
238 | of the General Public License from time to time.  Such new versions will
239 | be similar in spirit to the present version, but may differ in detail to
240 | address new problems or concerns.
241 | 
242 | Each version is given a distinguishing version number.  If the Program
243 | specifies a version number of this License which applies to it and "any
244 | later version", you have the option of following the terms and conditions
245 | either of that version or of any later version published by the Free
246 | Software Foundation.  If the Program does not specify a version number of
247 | this License, you may choose any version ever published by the Free Software
248 | Foundation.
249 | 
250 |   10. If you wish to incorporate parts of the Program into other free
251 | programs whose distribution conditions are different, write to the author
252 | to ask for permission.  For software which is copyrighted by the Free
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254 | make exceptions for this.  Our decision will be guided by the two goals
255 | of preserving the free status of all derivatives of our free software and
256 | of promoting the sharing and reuse of software generally.
257 | 
258 |                             NO WARRANTY
259 | 
260 |   11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
261 | FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW.  EXCEPT WHEN
262 | OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES
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266 | TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU.  SHOULD THE
267 | PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING,
268 | REPAIR OR CORRECTION.
269 | 
270 |   12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
271 | WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR
272 | REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES,
273 | INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING
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275 | TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY
276 | YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER
277 | PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE
278 | POSSIBILITY OF SUCH DAMAGES.
279 | 
280 |                      END OF TERMS AND CONDITIONS
281 | 
282 |             How to Apply These Terms to Your New Programs
283 | 
284 |   If you develop a new program, and you want it to be of the greatest
285 | possible use to the public, the best way to achieve this is to make it
286 | free software which everyone can redistribute and change under these terms.
287 | 
288 |   To do so, attach the following notices to the program.  It is safest
289 | to attach them to the start of each source file to most effectively
290 | convey the exclusion of warranty; and each file should have at least
291 | the "copyright" line and a pointer to where the full notice is found.
292 | 
293 |     {description}
294 |     Copyright (C) {year}  {fullname}
295 | 
296 |     This program is free software; you can redistribute it and/or modify
297 |     it under the terms of the GNU General Public License as published by
298 |     the Free Software Foundation; either version 2 of the License, or
299 |     (at your option) any later version.
300 | 
301 |     This program is distributed in the hope that it will be useful,
302 |     but WITHOUT ANY WARRANTY; without even the implied warranty of
303 |     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
304 |     GNU General Public License for more details.
305 | 
306 |     You should have received a copy of the GNU General Public License along
307 |     with this program; if not, write to the Free Software Foundation, Inc.,
308 |     51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
309 | 
310 | Also add information on how to contact you by electronic and paper mail.
311 | 
312 | If the program is interactive, make it output a short notice like this
313 | when it starts in an interactive mode:
314 | 
315 |     Gnomovision version 69, Copyright (C) year name of author
316 |     Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
317 |     This is free software, and you are welcome to redistribute it
318 |     under certain conditions; type `show c' for details.
319 | 
320 | The hypothetical commands `show w' and `show c' should show the appropriate
321 | parts of the General Public License.  Of course, the commands you use may
322 | be called something other than `show w' and `show c'; they could even be
323 | mouse-clicks or menu items--whatever suits your program.
324 | 
325 | You should also get your employer (if you work as a programmer) or your
326 | school, if any, to sign a "copyright disclaimer" for the program, if
327 | necessary.  Here is a sample; alter the names:
328 | 
329 |   Yoyodyne, Inc., hereby disclaims all copyright interest in the program
330 |   `Gnomovision' (which makes passes at compilers) written by James Hacker.
331 | 
332 |   {signature of Ty Coon}, 1 April 1989
333 |   Ty Coon, President of Vice
334 | 
335 | This General Public License does not permit incorporating your program into
336 | proprietary programs.  If your program is a subroutine library, you may
337 | consider it more useful to permit linking proprietary applications with the
338 | library.  If this is what you want to do, use the GNU Lesser General
339 | Public License instead of this License.
340 | 
341 | 


--------------------------------------------------------------------------------
/c4.c:
--------------------------------------------------------------------------------
  1 | // c4.c - C in four functions
  2 | 
  3 | // char, int, and pointer types
  4 | // if, while, return, and expression statements
  5 | // just enough features to allow self-compilation and a bit more
  6 | 
  7 | // Written by Robert Swierczek
  8 | 
  9 | #include <stdio.h>
 10 | #include <stdlib.h>
 11 | #include <memory.h>
 12 | #include <unistd.h>
 13 | #ifdef _WIN32
 14 | #include "w32.h"
 15 | #endif
 16 | 
 17 | char *p, *lp, // current position in source code
 18 |      *data;   // data/bss pointer
 19 | 
 20 | int *e, *le,  // current position in emitted code
 21 |     *id,      // currently parsed identifier
 22 |     *sym,     // symbol table (simple list of identifiers)
 23 |     tk,       // current token
 24 |     ival,     // current token value
 25 |     ty,       // current expression type
 26 |     loc,      // local variable offset
 27 |     line,     // current line number
 28 |     src,      // print source and assembly flag
 29 |     debug;    // print executed instructions
 30 | 
 31 | // tokens and classes (operators last and in precedence order)
 32 | enum {
 33 |   Num = 128, Fun, Sys, Glo, Loc, Id,
 34 |   Char, Else, Enum, If, Int, Return, Sizeof, While,
 35 |   Assign, Cond, Lor, Lan, Or, Xor, And, Eq, Ne, Lt, Gt, Le, Ge, Shl, Shr, Add, Sub, Mul, Div, Mod, Inc, Dec, Brak
 36 | };
 37 | 
 38 | // opcodes
 39 | enum { LEA ,IMM ,JMP ,JSR ,BZ  ,BNZ ,ENT ,ADJ ,LEV ,LI  ,LC  ,SI  ,SC  ,PSH ,
 40 |        OR  ,XOR ,AND ,EQ  ,NE  ,LT  ,GT  ,LE  ,GE  ,SHL ,SHR ,ADD ,SUB ,MUL ,DIV ,MOD ,
 41 |        OPEN,READ,CLOS,PRTF,MALC,MSET,MCMP,MCPY,MMAP,DSYM,QSRT,EXIT };
 42 | 
 43 | // types
 44 | enum { CHAR, INT, PTR };
 45 | 
 46 | // identifier offsets (since we can't create an ident struct)
 47 | enum { Tk, Hash, Name, Class, Type, Val, HClass, HType, HVal, Idsz };
 48 | 
 49 | void next()
 50 | {
 51 |   char *pp;
 52 | 
 53 |   while (tk = *p) {
 54 |     ++p;
 55 |     if (tk == '\n') {
 56 |       if (src) {
 57 |         printf("%d: %.*s", line, p - lp, lp);
 58 |         lp = p;
 59 |         while (le < e) {
 60 |           printf("%8.4s", &"LEA ,IMM ,JMP ,JSR ,BZ  ,BNZ ,ENT ,ADJ ,LEV ,LI  ,LC  ,SI  ,SC  ,PSH ,"
 61 |                            "OR  ,XOR ,AND ,EQ  ,NE  ,LT  ,GT  ,LE  ,GE  ,SHL ,SHR ,ADD ,SUB ,MUL ,DIV ,MOD ,"
 62 |                            "OPEN,READ,CLOS,PRTF,MALC,MSET,MCMP,MCPY,MMAP,DSYM,QSRT,EXIT,"[*++le * 5]);
 63 |           if (*le <= ADJ) printf(" %d\n", *++le); else printf("\n");
 64 |         }
 65 |       }
 66 |       ++line;
 67 |     }
 68 |     else if (tk == '#') {
 69 |       while (*p != 0 && *p != '\n') ++p;
 70 |     }
 71 |     else if ((tk >= 'a' && tk <= 'z') || (tk >= 'A' && tk <= 'Z') || tk == '_') {
 72 |       pp = p - 1;
 73 |       while ((*p >= 'a' && *p <= 'z') || (*p >= 'A' && *p <= 'Z') || (*p >= '0' && *p <= '9') || *p == '_')
 74 |         tk = tk * 147 + *p++;
 75 |       tk = (tk << 6) + (p - pp);
 76 |       id = sym;
 77 |       while (id[Tk]) {
 78 |         if (tk == id[Hash] && !memcmp((char *)id[Name], pp, p - pp)) { tk = id[Tk]; return; }
 79 |         id = id + Idsz;
 80 |       }
 81 |       id[Name] = (int)pp;
 82 |       id[Hash] = tk;
 83 |       tk = id[Tk] = Id;
 84 |       return;
 85 |     }
 86 |     else if (tk >= '0' && tk <= '9') {
 87 |       if (ival = tk - '0') { while (*p >= '0' && *p <= '9') ival = ival * 10 + *p++ - '0'; }
 88 |       else if (*p == 'x' || *p == 'X') {
 89 |         while ((tk = *++p) && ((tk >= '0' && tk <= '9') || (tk >= 'a' && tk <= 'f') || (tk >= 'A' && tk <= 'F')))
 90 |           ival = ival * 16 + (tk & 15) + (tk >= 'A' ? 9 : 0);
 91 |       }
 92 |       else { while (*p >= '0' && *p <= '7') ival = ival * 8 + *p++ - '0'; }
 93 |       tk = Num;
 94 |       return;
 95 |     }
 96 |     else if (tk == '/') {
 97 |       if (*p == '/') {
 98 |         ++p;
 99 |         while (*p != 0 && *p != '\n') ++p;
100 |       }
101 |       else {
102 |         tk = Div;
103 |         return;
104 |       }
105 |     }
106 |     else if (tk == '\'' || tk == '"') {
107 |       pp = data;
108 |       while (*p != 0 && *p != tk) {
109 |         if ((ival = *p++) == '\\') {
110 |           if ((ival = *p++) == 'n') ival = '\n';
111 |         }
112 |         if (tk == '"') *data++ = ival;
113 |       }
114 |       ++p;
115 |       if (tk == '"') ival = (int)pp; else tk = Num;
116 |       return;
117 |     }
118 |     else if (tk == '=') { if (*p == '=') { ++p; tk = Eq; } else tk = Assign; return; }
119 |     else if (tk == '+') { if (*p == '+') { ++p; tk = Inc; } else tk = Add; return; }
120 |     else if (tk == '-') { if (*p == '-') { ++p; tk = Dec; } else tk = Sub; return; }
121 |     else if (tk == '!') { if (*p == '=') { ++p; tk = Ne; } return; }
122 |     else if (tk == '<') { if (*p == '=') { ++p; tk = Le; } else if (*p == '<') { ++p; tk = Shl; } else tk = Lt; return; }
123 |     else if (tk == '>') { if (*p == '=') { ++p; tk = Ge; } else if (*p == '>') { ++p; tk = Shr; } else tk = Gt; return; }
124 |     else if (tk == '|') { if (*p == '|') { ++p; tk = Lor; } else tk = Or; return; }
125 |     else if (tk == '&') { if (*p == '&') { ++p; tk = Lan; } else tk = And; return; }
126 |     else if (tk == '^') { tk = Xor; return; }
127 |     else if (tk == '%') { tk = Mod; return; }
128 |     else if (tk == '*') { tk = Mul; return; }
129 |     else if (tk == '[') { tk = Brak; return; }
130 |     else if (tk == '?') { tk = Cond; return; }
131 |     else if (tk == '~' || tk == ';' || tk == '{' || tk == '}' || tk == '(' || tk == ')' || tk == ']' || tk == ',' || tk == ':') return;
132 |   }
133 | }
134 | 
135 | void expr(int lev)
136 | {
137 |   int t, *d;
138 | 
139 |   if (!tk) { printf("%d: unexpected eof in expression\n", line); exit(-1); }
140 |   else if (tk == Num) { *++e = IMM; *++e = ival; next(); ty = INT; }
141 |   else if (tk == '"') {
142 |     *++e = IMM; *++e = ival; next();
143 |     while (tk == '"') next();
144 |     data = (char *)((int)data + sizeof(int) & -sizeof(int)); ty = PTR;
145 |   }
146 |   else if (tk == Sizeof) {
147 |     next(); if (tk == '(') next(); else { printf("%d: open paren expected in sizeof\n", line); exit(-1); }
148 |     ty = INT; if (tk == Int) next(); else if (tk == Char) { next(); ty = CHAR; }
149 |     while (tk == Mul) { next(); ty = ty + PTR; }
150 |     if (tk == ')') next(); else { printf("%d: close paren expected in sizeof\n", line); exit(-1); }
151 |     *++e = IMM; *++e = (ty == CHAR) ? sizeof(char) : sizeof(int);
152 |     ty = INT;
153 |   }
154 |   else if (tk == Id) {
155 |     d = id; next();
156 |     if (tk == '(') {
157 |       next();
158 |       t = 0;
159 |       while (tk != ')') { expr(Assign); *++e = PSH; ++t; if (tk == ',') next(); }
160 |       next();
161 |       if (d[Class] == Sys) *++e = d[Val];
162 |       else if (d[Class] == Fun) { *++e = JSR; *++e = d[Val]; }
163 |       else { printf("%d: bad function call\n", line); exit(-1); }
164 |       if (t) { *++e = ADJ; *++e = t; }
165 |       ty = d[Type];
166 |     }
167 |     else if (d[Class] == Num) { *++e = IMM; *++e = d[Val]; ty = INT; }
168 |     else {
169 |       if (d[Class] == Loc) { *++e = LEA; *++e = loc - d[Val]; }
170 |       else if (d[Class] == Glo) { *++e = IMM; *++e = d[Val]; }
171 |       else { printf("%d: undefined variable\n", line); exit(-1); }
172 |       *++e = ((ty = d[Type]) == CHAR) ? LC : LI;
173 |     }
174 |   }
175 |   else if (tk == '(') {
176 |     next();
177 |     if (tk == Int || tk == Char) {
178 |       t = (tk == Int) ? INT : CHAR; next();
179 |       while (tk == Mul) { next(); t = t + PTR; }
180 |       if (tk == ')') next(); else { printf("%d: bad cast\n", line); exit(-1); }
181 |       expr(Inc);
182 |       ty = t;
183 |     }
184 |     else {
185 |       expr(Assign);
186 |       if (tk == ')') next(); else { printf("%d: close paren expected\n", line); exit(-1); }
187 |     }
188 |   }
189 |   else if (tk == Mul) {
190 |     next(); expr(Inc);
191 |     if (ty > INT) ty = ty - PTR; else { printf("%d: bad dereference\n", line); exit(-1); }
192 |     *++e = (ty == CHAR) ? LC : LI;
193 |   }
194 |   else if (tk == And) {
195 |     next(); expr(Inc);
196 |     if (*e == LC || *e == LI) --e; else { printf("%d: bad address-of\n", line); exit(-1); }
197 |     ty = ty + PTR;
198 |   }
199 |   else if (tk == '!') { next(); expr(Inc); *++e = PSH; *++e = IMM; *++e = 0; *++e = EQ; ty = INT; }
200 |   else if (tk == '~') { next(); expr(Inc); *++e = PSH; *++e = IMM; *++e = -1; *++e = XOR; ty = INT; }
201 |   else if (tk == Add) { next(); expr(Inc); ty = INT; }
202 |   else if (tk == Sub) {
203 |     next(); *++e = IMM;
204 |     if (tk == Num) { *++e = -ival; next(); } else { *++e = -1; *++e = PSH; expr(Inc); *++e = MUL; }
205 |     ty = INT;
206 |   }
207 |   else if (tk == Inc || tk == Dec) {
208 |     t = tk; next(); expr(Inc);
209 |     if (*e == LC) { *e = PSH; *++e = LC; }
210 |     else if (*e == LI) { *e = PSH; *++e = LI; }
211 |     else { printf("%d: bad lvalue in pre-increment\n", line); exit(-1); }
212 |     *++e = PSH;
213 |     *++e = IMM; *++e = (ty > PTR) ? sizeof(int) : sizeof(char);
214 |     *++e = (t == Inc) ? ADD : SUB;
215 |     *++e = (ty == CHAR) ? SC : SI;
216 |   }
217 |   else { printf("%d: bad expression\n", line); exit(-1); }
218 | 
219 |   while (tk >= lev) { // "precedence climbing" or "Top Down Operator Precedence" method
220 |     t = ty;
221 |     if (tk == Assign) {
222 |       next();
223 |       if (*e == LC || *e == LI) *e = PSH; else { printf("%d: bad lvalue in assignment\n", line); exit(-1); }
224 |       expr(Assign); *++e = ((ty = t) == CHAR) ? SC : SI;
225 |     }
226 |     else if (tk == Cond) {
227 |       next();
228 |       *++e = BZ; d = ++e;
229 |       expr(Assign);
230 |       if (tk == ':') next(); else { printf("%d: conditional missing colon\n", line); exit(-1); }
231 |       *d = (int)(e + 3); *++e = JMP; d = ++e;
232 |       expr(Cond);
233 |       *d = (int)(e + 1);
234 |     }
235 |     else if (tk == Lor) { next(); *++e = BNZ; d = ++e; expr(Lan); *d = (int)(e + 1); ty = INT; }
236 |     else if (tk == Lan) { next(); *++e = BZ;  d = ++e; expr(Or);  *d = (int)(e + 1); ty = INT; }
237 |     else if (tk == Or)  { next(); *++e = PSH; expr(Xor); *++e = OR;  ty = INT; }
238 |     else if (tk == Xor) { next(); *++e = PSH; expr(And); *++e = XOR; ty = INT; }
239 |     else if (tk == And) { next(); *++e = PSH; expr(Eq);  *++e = AND; ty = INT; }
240 |     else if (tk == Eq)  { next(); *++e = PSH; expr(Lt);  *++e = EQ;  ty = INT; }
241 |     else if (tk == Ne)  { next(); *++e = PSH; expr(Lt);  *++e = NE;  ty = INT; }
242 |     else if (tk == Lt)  { next(); *++e = PSH; expr(Shl); *++e = LT;  ty = INT; }
243 |     else if (tk == Gt)  { next(); *++e = PSH; expr(Shl); *++e = GT;  ty = INT; }
244 |     else if (tk == Le)  { next(); *++e = PSH; expr(Shl); *++e = LE;  ty = INT; }
245 |     else if (tk == Ge)  { next(); *++e = PSH; expr(Shl); *++e = GE;  ty = INT; }
246 |     else if (tk == Shl) { next(); *++e = PSH; expr(Add); *++e = SHL; ty = INT; }
247 |     else if (tk == Shr) { next(); *++e = PSH; expr(Add); *++e = SHR; ty = INT; }
248 |     else if (tk == Add) {
249 |       next(); *++e = PSH; expr(Mul);
250 |       if ((ty = t) > PTR) { *++e = PSH; *++e = IMM; *++e = sizeof(int); *++e = MUL;  }
251 |       *++e = ADD;
252 |     }
253 |     else if (tk == Sub) {
254 |       next(); *++e = PSH; expr(Mul);
255 |       if ((ty = t) > PTR) { *++e = PSH; *++e = IMM; *++e = sizeof(int); *++e = MUL;  }
256 |       *++e = SUB;
257 |     }
258 |     else if (tk == Mul) { next(); *++e = PSH; expr(Inc); *++e = MUL; ty = INT; }
259 |     else if (tk == Div) { next(); *++e = PSH; expr(Inc); *++e = DIV; ty = INT; }
260 |     else if (tk == Mod) { next(); *++e = PSH; expr(Inc); *++e = MOD; ty = INT; }
261 |     else if (tk == Inc || tk == Dec) {
262 |       if (*e == LC) { *e = PSH; *++e = LC; }
263 |       else if (*e == LI) { *e = PSH; *++e = LI; }
264 |       else { printf("%d: bad lvalue in post-increment\n", line); exit(-1); }
265 |       *++e = PSH; *++e = IMM; *++e = (ty > PTR) ? sizeof(int) : sizeof(char);
266 |       *++e = (tk == Inc) ? ADD : SUB;
267 |       *++e = (ty == CHAR) ? SC : SI;
268 |       *++e = PSH; *++e = IMM; *++e = (ty > PTR) ? sizeof(int) : sizeof(char);
269 |       *++e = (tk == Inc) ? SUB : ADD;
270 |       next();
271 |     }
272 |     else if (tk == Brak) {
273 |       next(); *++e = PSH; expr(Assign);
274 |       if (tk == ']') next(); else { printf("%d: close bracket expected\n", line); exit(-1); }
275 |       if (t > PTR) { *++e = PSH; *++e = IMM; *++e = sizeof(int); *++e = MUL;  }
276 |       else if (t < PTR) { printf("%d: pointer type expected\n", line); exit(-1); }
277 |       *++e = ADD;
278 |       *++e = ((ty = t - PTR) == CHAR) ? LC : LI;
279 |     }
280 |     else { printf("%d: compiler error tk=%d\n", line, tk); exit(-1); }
281 |   }
282 | }
283 | 
284 | void stmt()
285 | {
286 |   int *a, *b;
287 | 
288 |   if (tk == If) {
289 |     next();
290 |     if (tk == '(') next(); else { printf("%d: open paren expected\n", line); exit(-1); }
291 |     expr(Assign);
292 |     if (tk == ')') next(); else { printf("%d: close paren expected\n", line); exit(-1); }
293 |     *++e = BZ; b = ++e;
294 |     stmt();
295 |     if (tk == Else) {
296 |       *b = (int)(e + 3); *++e = JMP; b = ++e;
297 |       next();
298 |       stmt();
299 |     }
300 |     *b = (int)(e + 1);
301 |   }
302 |   else if (tk == While) {
303 |     next();
304 |     a = e + 1;
305 |     if (tk == '(') next(); else { printf("%d: open paren expected\n", line); exit(-1); }
306 |     expr(Assign);
307 |     if (tk == ')') next(); else { printf("%d: close paren expected\n", line); exit(-1); }
308 |     *++e = BZ; b = ++e;
309 |     stmt();
310 |     *++e = JMP; *++e = (int)a;
311 |     *b = (int)(e + 1);
312 |   }
313 |   else if (tk == Return) {
314 |     next();
315 |     if (tk != ';') expr(Assign);
316 |     *++e = LEV;
317 |     if (tk == ';') next(); else { printf("%d: semicolon expected\n", line); exit(-1); }
318 |   }
319 |   else if (tk == '{') {
320 |     next();
321 |     while (tk != '}') stmt();
322 |     next();
323 |   }
324 |   else if (tk == ';') {
325 |     next();
326 |   }
327 |   else {
328 |     expr(Assign);
329 |     if (tk == ';') next(); else { printf("%d: semicolon expected\n", line); exit(-1); }
330 |   }
331 | }
332 | 
333 | int main(int argc, char **argv)
334 | {
335 |   int fd, bt, ty, poolsz, *idmain;
336 |   int *pc, *sp, *bp, a, cycle; // vm registers
337 |   int i, *t; // temps
338 | 
339 |   --argc; ++argv;
340 |   if (argc > 0 && **argv == '-' && (*argv)[1] == 's') { src = 1; --argc; ++argv; }
341 |   if (argc > 0 && **argv == '-' && (*argv)[1] == 'd') { debug = 1; --argc; ++argv; }
342 |   if (argc < 1) { printf("usage: c4 [-s] [-d] file ...\n"); return -1; }
343 | 
344 |   if ((fd = open(*argv, 0)) < 0) { printf("could not open(%s)\n", *argv); return -1; }
345 | 
346 |   poolsz = 256*1024; // arbitrary size
347 |   if (!(sym = malloc(poolsz))) { printf("could not malloc(%d) symbol area\n", poolsz); return -1; }
348 |   if (!(le = e = malloc(poolsz))) { printf("could not malloc(%d) text area\n", poolsz); return -1; }
349 |   if (!(data = malloc(poolsz))) { printf("could not malloc(%d) data area\n", poolsz); return -1; }
350 |   if (!(sp = malloc(poolsz))) { printf("could not malloc(%d) stack area\n", poolsz); return -1; }
351 | 
352 |   memset(sym,  0, poolsz);
353 |   memset(e,    0, poolsz);
354 |   memset(data, 0, poolsz);
355 | 
356 |   p = "char else enum if int return sizeof while "
357 |       "open read close printf malloc memset memcmp memcpy mmap dlsym qsort exit void main";
358 |   i = Char; while (i <= While) { next(); id[Tk] = i++; } // add keywords to symbol table
359 |   i = OPEN; while (i <= EXIT) { next(); id[Class] = Sys; id[Type] = INT; id[Val] = i++; } // add library to symbol table
360 |   next(); id[Tk] = Char; // handle void type
361 |   next(); idmain = id; // keep track of main
362 | 
363 |   if (!(lp = p = malloc(poolsz))) { printf("could not malloc(%d) source area\n", poolsz); return -1; }
364 |   if ((i = read(fd, p, poolsz-1)) <= 0) { printf("read() returned %d\n", i); return -1; }
365 |   p[i] = 0;
366 |   close(fd);
367 | 
368 |   // parse declarations
369 |   line = 1;
370 |   next();
371 |   while (tk) {
372 |     bt = INT; // basetype
373 |     if (tk == Int) next();
374 |     else if (tk == Char) { next(); bt = CHAR; }
375 |     else if (tk == Enum) {
376 |       next();
377 |       if (tk != '{') next();
378 |       if (tk == '{') {
379 |         next();
380 |         i = 0;
381 |         while (tk != '}') {
382 |           if (tk != Id) { printf("%d: bad enum identifier %d\n", line, tk); return -1; }
383 |           next();
384 |           if (tk == Assign) {
385 |             next();
386 |             if (tk != Num) { printf("%d: bad enum initializer\n", line); return -1; }
387 |             i = ival;
388 |             next();
389 |           }
390 |           id[Class] = Num; id[Type] = INT; id[Val] = i++;
391 |           if (tk == ',') next();
392 |         }
393 |         next();
394 |       }
395 |     }
396 |     while (tk != ';' && tk != '}') {
397 |       ty = bt;
398 |       while (tk == Mul) { next(); ty = ty + PTR; }
399 |       if (tk != Id) { printf("%d: bad global declaration\n", line); return -1; }
400 |       if (id[Class]) { printf("%d: duplicate global definition\n", line); return -1; }
401 |       next();
402 |       id[Type] = ty;
403 |       if (tk == '(') { // function
404 |         id[Class] = Fun;
405 |         id[Val] = (int)(e + 1);
406 |         next(); i = 0;
407 |         while (tk != ')') {
408 |           ty = INT;
409 |           if (tk == Int) next();
410 |           else if (tk == Char) { next(); ty = CHAR; }
411 |           while (tk == Mul) { next(); ty = ty + PTR; }
412 |           if (tk != Id) { printf("%d: bad parameter declaration\n", line); return -1; }
413 |           if (id[Class] == Loc) { printf("%d: duplicate parameter definition\n", line); return -1; }
414 |           id[HClass] = id[Class]; id[Class] = Loc;
415 |           id[HType]  = id[Type];  id[Type] = ty;
416 |           id[HVal]   = id[Val];   id[Val] = i++;
417 |           next();
418 |           if (tk == ',') next();
419 |         }
420 |         next();
421 |         if (tk != '{') { printf("%d: bad function definition\n", line); return -1; }
422 |         loc = ++i;
423 |         next();
424 |         while (tk == Int || tk == Char) {
425 |           bt = (tk == Int) ? INT : CHAR;
426 |           next();
427 |           while (tk != ';') {
428 |             ty = bt;
429 |             while (tk == Mul) { next(); ty = ty + PTR; }
430 |             if (tk != Id) { printf("%d: bad local declaration\n", line); return -1; }
431 |             if (id[Class] == Loc) { printf("%d: duplicate local definition\n", line); return -1; }
432 |             id[HClass] = id[Class]; id[Class] = Loc;
433 |             id[HType]  = id[Type];  id[Type] = ty;
434 |             id[HVal]   = id[Val];   id[Val] = ++i;
435 |             next();
436 |             if (tk == ',') next();
437 |           }
438 |           next();
439 |         }
440 |         *++e = ENT; *++e = i - loc;
441 |         while (tk != '}') stmt();
442 |         *++e = LEV;
443 |         id = sym; // unwind symbol table locals
444 |         while (id[Tk]) {
445 |           if (id[Class] == Loc) {
446 |             id[Class] = id[HClass];
447 |             id[Type] = id[HType];
448 |             id[Val] = id[HVal];
449 |           }
450 |           id = id + Idsz;
451 |         }
452 |       }
453 |       else {
454 |         id[Class] = Glo;
455 |         id[Val] = (int)data;
456 |         data = data + sizeof(int);
457 |       }
458 |       if (tk == ',') next();
459 |     }
460 |     next();
461 |   }
462 | 
463 |   if (!(pc = (int *)idmain[Val])) { printf("main() not defined\n"); return -1; }
464 |   if (src) return 0;
465 | 
466 |   // setup stack
467 |   sp = (int *)((int)sp + poolsz);
468 |   *--sp = EXIT; // call exit if main returns
469 |   *--sp = PSH; t = sp;
470 |   *--sp = argc;
471 |   *--sp = (int)argv;
472 |   *--sp = (int)t;
473 | 
474 |   // run...
475 |   cycle = 0;
476 |   while (1) {
477 |     i = *pc++; ++cycle;
478 |     if (debug) {
479 |       printf("%d> %.4s", cycle,
480 |         &"LEA ,IMM ,JMP ,JSR ,BZ  ,BNZ ,ENT ,ADJ ,LEV ,LI  ,LC  ,SI  ,SC  ,PSH ,"
481 |          "OR  ,XOR ,AND ,EQ  ,NE  ,LT  ,GT  ,LE  ,GE  ,SHL ,SHR ,ADD ,SUB ,MUL ,DIV ,MOD ,"
482 |          "OPEN,READ,CLOS,PRTF,MALC,MSET,MCMP,MCPY,MMAP,DSYM,QSRT,EXIT,"[i * 5]);
483 |       if (i <= ADJ) printf(" %d\n", *pc); else printf("\n");
484 |     }
485 |     if      (i == LEA) a = (int)(bp + *pc++);                             // load local address
486 |     else if (i == IMM) a = *pc++;                                         // load global address or immediate
487 |     else if (i == JMP) pc = (int *)*pc;                                   // jump
488 |     else if (i == JSR) { *--sp = (int)(pc + 1); pc = (int *)*pc; }        // jump to subroutine
489 |     else if (i == BZ)  pc = a ? pc + 1 : (int *)*pc;                      // branch if zero
490 |     else if (i == BNZ) pc = a ? (int *)*pc : pc + 1;                      // branch if not zero
491 |     else if (i == ENT) { *--sp = (int)bp; bp = sp; sp = sp - *pc++; }     // enter subroutine
492 |     else if (i == ADJ) sp = sp + *pc++;                                   // stack adjust
493 |     else if (i == LEV) { sp = bp; bp = (int *)*sp++; pc = (int *)*sp++; } // leave subroutine
494 |     else if (i == LI)  a = *(int *)a;                                     // load int
495 |     else if (i == LC)  a = *(char *)a;                                    // load char
496 |     else if (i == SI)  *(int *)*sp++ = a;                                 // store int
497 |     else if (i == SC)  a = *(char *)*sp++ = a;                            // store char
498 |     else if (i == PSH) *--sp = a;                                         // push
499 | 
500 |     else if (i == OR)  a = *sp++ |  a;
501 |     else if (i == XOR) a = *sp++ ^  a;
502 |     else if (i == AND) a = *sp++ &  a;
503 |     else if (i == EQ)  a = *sp++ == a;
504 |     else if (i == NE)  a = *sp++ != a;
505 |     else if (i == LT)  a = *sp++ <  a;
506 |     else if (i == GT)  a = *sp++ >  a;
507 |     else if (i == LE)  a = *sp++ <= a;
508 |     else if (i == GE)  a = *sp++ >= a;
509 |     else if (i == SHL) a = *sp++ << a;
510 |     else if (i == SHR) a = *sp++ >> a;
511 |     else if (i == ADD) a = *sp++ +  a;
512 |     else if (i == SUB) a = *sp++ -  a;
513 |     else if (i == MUL) a = *sp++ *  a;
514 |     else if (i == DIV) a = *sp++ /  a;
515 |     else if (i == MOD) a = *sp++ %  a;
516 | 
517 |     else if (i == OPEN) a = open((char *)sp[1], *sp);
518 |     else if (i == READ) a = read(sp[2], (char *)sp[1], *sp);
519 |     else if (i == CLOS) a = close(*sp);
520 |     else if (i == PRTF) { t = sp + pc[1]; a = printf((char *)t[-1], t[-2], t[-3], t[-4], t[-5], t[-6]); }
521 |     else if (i == MALC) a = (int)malloc(*sp);
522 |     else if (i == MSET) a = (int)memset((char *)sp[2], sp[1], *sp);
523 |     else if (i == MCMP) a = memcmp((char *)sp[2], (char *)sp[1], *sp);
524 |     else if (i == MCPY) a = (int)memcpy((char *)sp[2], (char *)sp[1], *sp);
525 |     else if (i == MMAP) a = (int)mmap((char *)sp[5], sp[4], sp[3], sp[2], sp[1], *sp);
526 |     else if (i == DSYM) a = (int)dlsym((char *)sp[1], (char *)*sp);
527 |     else if (i == QSRT) qsort((char *)sp[3], sp[2], sp[1], (void *)*sp);
528 |     else if (i == EXIT) { printf("exit(%d) cycle = %d\n", *sp, cycle); return *sp; }
529 |     else { printf("unknown instruction = %d! cycle = %d\n", i, cycle); return -1; }
530 |   }
531 | }
532 | 


--------------------------------------------------------------------------------
/c4x86.c:
--------------------------------------------------------------------------------
  1 | // c4.c - C in four functions
  2 | 
  3 | // char, int, and pointer types
  4 | // if, while, return, and expression statements
  5 | // just enough features to allow self-compilation and a bit more
  6 | 
  7 | // Written by Robert Swierczek
  8 | // + x86 JIT compiler by Dmytro Sirenko
  9 | 
 10 | #include <stdio.h>
 11 | #include <stdlib.h>
 12 | #include <memory.h>
 13 | #ifndef _WIN32
 14 | #include <sys/mman.h>
 15 | #include <dlfcn.h>
 16 | #else
 17 | #include "mman32.h"
 18 | #include "dlfcn32.h"
 19 | #define CHAR TYCHAR
 20 | #define INT TYINT
 21 | #endif
 22 | 
 23 | char *p, *lp, // current position in source code
 24 |      *jitmem, // executable memory for JIT-compiled native code
 25 |      *data,   // data/bss pointer
 26 |      **linemap; // maps a line number into its source position
 27 | 
 28 | int *e, *le, *text, // current position in emitted code
 29 |     *id,      // currently parsed indentifier
 30 |     *sym,     // symbol table (simple list of identifiers)
 31 |     tk,       // current token
 32 |     ival,     // current token value
 33 |     ty,       // current expression type
 34 |     loc,      // local variable offset
 35 |     line,     // current line number
 36 |     *srcmap,  // maps a bytecode into its corresponding source line number
 37 |     src;      // print source, c4 assembly and JIT addresses
 38 | 
 39 | enum Token {
 40 |   Num = 128, Fun, Sys, Glo, Loc, Id,
 41 |   Char, Else, Enum, If, Int, Return, Sizeof, While,
 42 |   Assign, Cond, Lor, Lan, Or, Xor, And, Eq, Ne, Lt, Gt, Le, Ge, Shl, Shr, Add, Sub, Mul, Div, Mod, Inc, Dec, Brak
 43 | };
 44 | 
 45 | enum Opcode {
 46 |   LEA ,IMM ,JMP ,JSR ,BZ  ,BNZ ,ENT ,ADJ ,LEV ,LI  ,LC  ,SI  ,SC  ,PSH ,
 47 |   OR  ,XOR ,AND ,EQ  ,NE  ,LT  ,GT  ,LE  ,GE  ,SHL ,SHR ,ADD ,SUB ,MUL ,DIV ,MOD ,
 48 |   OPEN,READ,CLOS,PRTF,MALC,MSET,MCMP,MCPY,MMAP,DOPN,DSYM,QSRT,EXIT
 49 | };
 50 | 
 51 | enum Ty { CHAR, INT, PTR };
 52 | 
 53 | // identifier offsets (since we can't create an ident struct)
 54 | enum Identifier { Tk, Hash, Name, Class, Type, Val, HClass, HType, HVal, Idsz };
 55 | 
 56 | void next()
 57 | {
 58 |   char *pp;
 59 | 
 60 |   while (tk = *p) {
 61 |     ++p;
 62 |     if (tk == '\n') {
 63 |       if (src) {
 64 |         linemap[line] = lp;
 65 |         while (le < e) { srcmap[le - text] = line; le++; };
 66 |       }
 67 |       lp = p;
 68 |       ++line;
 69 |     }
 70 |     else if (tk == '#') {
 71 |       while (*p != 0 && *p != '\n') ++p;
 72 |     }
 73 |     else if ((tk >= 'a' && tk <= 'z') || (tk >= 'A' && tk <= 'Z') || tk == '_') {
 74 |       pp = p - 1;
 75 |       while ((*p >= 'a' && *p <= 'z') || (*p >= 'A' && *p <= 'Z') || (*p >= '0' && *p <= '9') || *p == '_')
 76 |         tk = tk * 147 + *p++;
 77 |       tk = (tk << 6) + (p - pp);
 78 |       id = sym;
 79 |       while (id[Tk]) {
 80 |         if (tk == id[Hash] && !memcmp((char *)id[Name], pp, p - pp)) { tk = id[Tk]; return; }
 81 |         id = id + Idsz;
 82 |       }
 83 |       id[Name] = (int)pp;
 84 |       id[Hash] = tk;
 85 |       tk = id[Tk] = Id;
 86 |       return;
 87 |     }
 88 |     else if (tk >= '0' && tk <= '9') {
 89 |       if (ival = tk - '0') { while (*p >= '0' && *p <= '9') ival = ival * 10 + *p++ - '0'; }
 90 |       else if (*p == 'x' || *p == 'X') {
 91 |         while ((tk = *++p) && ((tk >= '0' && tk <= '9') || (tk >= 'a' && tk <= 'f') || (tk >= 'A' && tk <= 'F')))
 92 |           ival = ival * 16 + (tk & 15) + (tk >= 'A' ? 9 : 0);
 93 |       }
 94 |       else { while (*p >= '0' && *p <= '7') ival = ival * 8 + *p++ - '0'; }
 95 |       tk = Num;
 96 |       return;
 97 |     }
 98 |     else if (tk == '/') {
 99 |       if (*p == '/') {
100 |         ++p;
101 |         while (*p != 0 && *p != '\n') ++p;
102 |       }
103 |       else {
104 |         tk = Div;
105 |         return;
106 |       }
107 |     }
108 |     else if (tk == '\'' || tk == '"') {
109 |       pp = data;
110 |       while (*p != 0 && *p != tk) {
111 |         if ((ival = *p++) == '\\') {
112 |           if ((ival = *p++) == 'n') ival = '\n';
113 |         }
114 |         if (tk == '"') *data++ = ival;
115 |       }
116 |       ++p;
117 |       if (tk == '"') ival = (int)pp; else tk = Num;
118 |       return;
119 |     }
120 |     else if (tk == '=') { if (*p == '=') { ++p; tk = Eq; } else tk = Assign; return; }
121 |     else if (tk == '+') { if (*p == '+') { ++p; tk = Inc; } else tk = Add; return; }
122 |     else if (tk == '-') { if (*p == '-') { ++p; tk = Dec; } else tk = Sub; return; }
123 |     else if (tk == '!') { if (*p == '=') { ++p; tk = Ne; } return; }
124 |     else if (tk == '<') { if (*p == '=') { ++p; tk = Le; } else if (*p == '<') { ++p; tk = Shl; } else tk = Lt; return; }
125 |     else if (tk == '>') { if (*p == '=') { ++p; tk = Ge; } else if (*p == '>') { ++p; tk = Shr; } else tk = Gt; return; }
126 |     else if (tk == '|') { if (*p == '|') { ++p; tk = Lor; } else tk = Or; return; }
127 |     else if (tk == '&') { if (*p == '&') { ++p; tk = Lan; } else tk = And; return; }
128 |     else if (tk == '^') { tk = Xor; return; }
129 |     else if (tk == '%') { tk = Mod; return; }
130 |     else if (tk == '*') { tk = Mul; return; }
131 |     else if (tk == '[') { tk = Brak; return; }
132 |     else if (tk == '?') { tk = Cond; return; }
133 |     else if (tk == '~' || tk == ';' || tk == '{' || tk == '}' || tk == '(' || tk == ')' || tk == ']' || tk == ',' || tk == ':') return;
134 |   }
135 | }
136 | 
137 | void expr(int lev)
138 | {
139 |   int t, *d;
140 | 
141 |   if (!tk) { printf("%d: unexpected eof in expression\n", line); exit(-1); }
142 |   else if (tk == Num) { *++e = IMM; *++e = ival; next(); ty = INT; }
143 |   else if (tk == '"') {
144 |     *++e = IMM; *++e = ival; next();
145 |     while (tk == '"') next();
146 |     data = (char *)((int)data + sizeof(int) & -sizeof(int)); ty = PTR;
147 |   }
148 |   else if (tk == Sizeof) {
149 |     next(); if (tk == '(') next(); else { printf("%d: open paren expected in sizeof\n", line); exit(-1); }
150 |     ty = INT; if (tk == Int) next(); else if (tk == Char) { next(); ty = CHAR; }
151 |     while (tk == Mul) { next(); ty = ty + PTR; }
152 |     if (tk == ')') next(); else { printf("%d: close paren expected in sizeof\n", line); exit(-1); }
153 |     *++e = IMM; *++e = (ty == CHAR) ? sizeof(char) : sizeof(int);
154 |     ty = INT;
155 |   }
156 |   else if (tk == Id) {
157 |     d = id; next();
158 |     if (tk == '(') {
159 |       next();
160 |       t = 0;
161 |       while (tk != ')') { expr(Assign); *++e = PSH; ++t; if (tk == ',') next(); }
162 |       next();
163 |       if (d[Class] == Sys) *++e = d[Val];
164 |       else if (d[Class] == Fun) { *++e = JSR; *++e = d[Val]; }
165 |       else { printf("%d: bad function call\n", line); exit(-1); }
166 |       if (t) { *++e = ADJ; *++e = t; }
167 |       ty = d[Type];
168 |     }
169 |     else if (d[Class] == Num) { *++e = IMM; *++e = d[Val]; ty = INT; }
170 |     else {
171 |       if (d[Class] == Loc) { *++e = LEA; *++e = loc - d[Val]; }
172 |       else if (d[Class] == Glo) { *++e = IMM; *++e = d[Val]; }
173 |       else { printf("%d: undefined variable\n", line); exit(-1); }
174 |       *++e = ((ty = d[Type]) == CHAR) ? LC : LI;
175 |     }
176 |   }
177 |   else if (tk == '(') {
178 |     next();
179 |     if (tk == Int || tk == Char) {
180 |       t = (tk == Int) ? INT : CHAR; next();
181 |       while (tk == Mul) { next(); t = t + PTR; }
182 |       if (tk == ')') next(); else { printf("%d: bad cast\n", line); exit(-1); }
183 |       expr(Inc);
184 |       ty = t;
185 |     }
186 |     else {
187 |       expr(Assign);
188 |       if (tk == ')') next(); else { printf("%d: close paren expected\n", line); exit(-1); }
189 |     }
190 |   }
191 |   else if (tk == Mul) {
192 |     next(); expr(Inc);
193 |     if (ty > INT) ty = ty - PTR; else { printf("%d: bad dereference\n", line); exit(-1); }
194 |     *++e = (ty == CHAR) ? LC : LI;
195 |   }
196 |   else if (tk == And) {
197 |     next(); expr(Inc);
198 |     if (*e == LC || *e == LI) --e; else { printf("%d: bad address-of\n", line); exit(-1); }
199 |     ty = ty + PTR;
200 |   }
201 |   else if (tk == '!') { next(); expr(Inc); *++e = PSH; *++e = IMM; *++e = 0; *++e = EQ; ty = INT; }
202 |   else if (tk == '~') { next(); expr(Inc); *++e = PSH; *++e = IMM; *++e = -1; *++e = XOR; ty = INT; }
203 |   else if (tk == Add) { next(); expr(Inc); ty = INT; }
204 |   else if (tk == Sub) {
205 |     next(); *++e = IMM;
206 |     if (tk == Num) { *++e = -ival; next(); } else { *++e = -1; *++e = PSH; expr(Inc); *++e = MUL; }
207 |     ty = INT;
208 |   }
209 |   else if (tk == Inc || tk == Dec) {
210 |     t = tk; next(); expr(Inc);
211 |     if (*e == LC) { *e = PSH; *++e = LC; }
212 |     else if (*e == LI) { *e = PSH; *++e = LI; }
213 |     else { printf("%d: bad lvalue in pre-increment\n", line); exit(-1); }
214 |     *++e = PSH;
215 |     *++e = IMM; *++e = (ty > PTR) ? sizeof(int) : sizeof(char);
216 |     *++e = (t == Inc) ? ADD : SUB;
217 |     *++e = (ty == CHAR) ? SC : SI;
218 |   }
219 |   else { printf("%d: bad expression\n", line); exit(-1); }
220 | 
221 |   while (tk >= lev) { // "precedence climbing" or "Top Down Operator Precedence" method
222 |     t = ty;
223 |     if (tk == Assign) {
224 |       next();
225 |       if (*e == LC || *e == LI) *e = PSH; else { printf("%d: bad lvalue in assignment\n", line); exit(-1); }
226 |       expr(Assign); *++e = ((ty = t) == CHAR) ? SC : SI;
227 |     }
228 |     else if (tk == Cond) {
229 |       next();
230 |       *++e = BZ; d = ++e;
231 |       expr(Assign);
232 |       if (tk == ':') next(); else { printf("%d: conditional missing colon\n", line); exit(-1); }
233 |       *d = (int)(e + 3); *++e = JMP; d = ++e;
234 |       expr(Cond);
235 |       *d = (int)(e + 1);
236 |     }
237 |     else if (tk == Lor) { next(); *++e = BNZ; d = ++e; expr(Lan); *d = (int)(e + 1); ty = INT; }
238 |     else if (tk == Lan) { next(); *++e = BZ;  d = ++e; expr(Or);  *d = (int)(e + 1); ty = INT; }
239 |     else if (tk == Or)  { next(); *++e = PSH; expr(Xor); *++e = OR;  ty = INT; }
240 |     else if (tk == Xor) { next(); *++e = PSH; expr(And); *++e = XOR; ty = INT; }
241 |     else if (tk == And) { next(); *++e = PSH; expr(Eq);  *++e = AND; ty = INT; }
242 |     else if (tk == Eq)  { next(); *++e = PSH; expr(Lt);  *++e = EQ;  ty = INT; }
243 |     else if (tk == Ne)  { next(); *++e = PSH; expr(Lt);  *++e = NE;  ty = INT; }
244 |     else if (tk == Lt)  { next(); *++e = PSH; expr(Shl); *++e = LT;  ty = INT; }
245 |     else if (tk == Gt)  { next(); *++e = PSH; expr(Shl); *++e = GT;  ty = INT; }
246 |     else if (tk == Le)  { next(); *++e = PSH; expr(Shl); *++e = LE;  ty = INT; }
247 |     else if (tk == Ge)  { next(); *++e = PSH; expr(Shl); *++e = GE;  ty = INT; }
248 |     else if (tk == Shl) { next(); *++e = PSH; expr(Add); *++e = SHL; ty = INT; }
249 |     else if (tk == Shr) { next(); *++e = PSH; expr(Add); *++e = SHR; ty = INT; }
250 |     else if (tk == Add) {
251 |       next(); *++e = PSH; expr(Mul);
252 |       if ((ty = t) > PTR) { *++e = PSH; *++e = IMM; *++e = sizeof(int); *++e = MUL;  }
253 |       *++e = ADD;
254 |     }
255 |     else if (tk == Sub) {
256 |       next(); *++e = PSH; expr(Mul);
257 |       if ((ty = t) > PTR) { *++e = PSH; *++e = IMM; *++e = sizeof(int); *++e = MUL;  }
258 |       *++e = SUB;
259 |     }
260 |     else if (tk == Mul) { next(); *++e = PSH; expr(Inc); *++e = MUL; ty = INT; }
261 |     else if (tk == Div) { next(); *++e = PSH; expr(Inc); *++e = DIV; ty = INT; }
262 |     else if (tk == Mod) { next(); *++e = PSH; expr(Inc); *++e = MOD; ty = INT; }
263 |     else if (tk == Inc || tk == Dec) {
264 |       if (*e == LC) { *e = PSH; *++e = LC; }
265 |       else if (*e == LI) { *e = PSH; *++e = LI; }
266 |       else { printf("%d: bad lvalue in post-increment\n", line); exit(-1); }
267 |       *++e = PSH; *++e = IMM; *++e = (ty > PTR) ? sizeof(int) : sizeof(char);
268 |       *++e = (tk == Inc) ? ADD : SUB;
269 |       *++e = (ty == CHAR) ? SC : SI;
270 |       *++e = PSH; *++e = IMM; *++e = (ty > PTR) ? sizeof(int) : sizeof(char);
271 |       *++e = (tk == Inc) ? SUB : ADD;
272 |       next();
273 |     }
274 |     else if (tk == Brak) {
275 |       next(); *++e = PSH; expr(Assign);
276 |       if (tk == ']') next(); else { printf("%d: close bracket expected\n", line); exit(-1); }
277 |       if (t > PTR) { *++e = PSH; *++e = IMM; *++e = sizeof(int); *++e = MUL;  }
278 |       else if (t < PTR) { printf("%d: pointer type expected\n", line); exit(-1); }
279 |       *++e = ADD;
280 |       *++e = ((ty = t - PTR) == CHAR) ? LC : LI;
281 |     }
282 |     else { printf("%d: compiler error tk=%d\n", line, tk); exit(-1); }
283 |   }
284 | }
285 | 
286 | void stmt()
287 | {
288 |   int *a, *b;
289 | 
290 |   if (tk == If) {
291 |     next();
292 |     if (tk == '(') next(); else { printf("%d: open paren expected\n", line); exit(-1); }
293 |     expr(Assign);
294 |     if (tk == ')') next(); else { printf("%d: close paren expected\n", line); exit(-1); }
295 |     *++e = BZ; b = ++e;
296 |     stmt();
297 |     if (tk == Else) {
298 |       *b = (int)(e + 3); *++e = JMP; b = ++e;
299 |       next();
300 |       stmt();
301 |     }
302 |     *b = (int)(e + 1);
303 |   }
304 |   else if (tk == While) {
305 |     next();
306 |     a = e + 1;
307 |     if (tk == '(') next(); else { printf("%d: open paren expected\n", line); exit(-1); }
308 |     expr(Assign);
309 |     if (tk == ')') next(); else { printf("%d: close paren expected\n", line); exit(-1); }
310 |     *++e = BZ; b = ++e;
311 |     stmt();
312 |     *++e = JMP; *++e = (int)a;
313 |     *b = (int)(e + 1);
314 |   }
315 |   else if (tk == Return) {
316 |     next();
317 |     if (tk != ';') expr(Assign);
318 |     *++e = LEV;
319 |     if (tk == ';') next(); else { printf("%d: semicolon expected\n", line); exit(-1); }
320 |   }
321 |   else if (tk == '{') {
322 |     next();
323 |     while (tk != '}') stmt();
324 |     next();
325 |   }
326 |   else if (tk == ';') {
327 |     next();
328 |   }
329 |   else {
330 |     expr(Assign);
331 |     if (tk == ';') next(); else { printf("%d: semicolon expected\n", line); exit(-1); }
332 |   }
333 | }
334 | 
335 | int main(int argc, char **argv)
336 | {
337 |   int fd, bt, ty, poolsz, *idmain;
338 |   int *pc;
339 |   int i, tmp; // temps
340 |   void *dl;
341 |   int (*jitmain)();
342 |   char *je,      // current position in emitted native code
343 |        **jitmap;  // maps c4 bytecode index into native code position
344 | 
345 |   --argc; ++argv;
346 |   if (argc > 0 && **argv == '-' && (*argv)[1] == 's') { src = 1; --argc; ++argv; }
347 |   if (argc < 1) { printf("usage: c4x86 [-s] file ...\n"); return -1; }
348 | 
349 |   if ((fd = open(*argv, 0)) < 0) { printf("could not open(%s)\n", *argv); return -1; }
350 | 
351 |   poolsz = 256*1024; // arbitrary size
352 |   if (!(sym = malloc(poolsz))) { printf("could not malloc(%d) symbol area\n", poolsz); return -1; }
353 |   if (!(text = le = e = malloc(poolsz))) { printf("could not malloc(%d) text area\n", poolsz); return -1; }
354 |   if (!(data = malloc(poolsz))) { printf("could not malloc(%d) data area\n", poolsz); return -1; }
355 | 
356 |   memset(sym,  0, poolsz);
357 |   memset(e,    0, poolsz);
358 |   memset(data, 0, poolsz);
359 | 
360 |   p = "char else enum if int return sizeof while "
361 |       "open read close printf malloc memset memcmp memcpy mmap dlopen dlsym qsort exit void main";
362 |   i = Char; while (i <= While) { next(); id[Tk] = i++; } // add keywords to symbol table
363 |   i = OPEN; while (i <= EXIT) { next(); id[Class] = Sys; id[Type] = INT; id[Val] = i++; } // add library to symbol table
364 |   next(); id[Tk] = Char; // handle void type
365 |   next(); idmain = id; // keep track of main
366 | 
367 |   if (!(lp = p = malloc(poolsz))) { printf("could not malloc(%d) source area\n", poolsz); return -1; }
368 |   if ((i = read(fd, p, poolsz-1)) <= 0) { printf("read() returned %d\n", i); return -1; }
369 |   close(fd);
370 |   p[i] = 0;
371 |   if (src) {
372 |     linemap = (char **)(((int)(p + i + 1) & 0xffffff00) + 0x100);
373 |     srcmap = text + (poolsz / 8);
374 |   }
375 | 
376 |   // parse declarations
377 |   line = 1;
378 |   next();
379 |   while (tk) {
380 |     bt = INT; // basetype
381 |     if (tk == Int) next();
382 |     else if (tk == Char) { next(); bt = CHAR; }
383 |     else if (tk == Enum) {
384 |       next();
385 |       if (tk != '{') next();
386 |       if (tk == '{') {
387 |         next();
388 |         i = 0;
389 |         while (tk != '}') {
390 |           if (tk != Id) { printf("%d: bad enum identifier %d\n", line, tk); return -1; }
391 |           next();
392 |           if (tk == Assign) {
393 |             next();
394 |             if (tk != Num) { printf("%d: bad enum initializer\n", line); return -1; }
395 |             i = ival;
396 |             next();
397 |           }
398 |           id[Class] = Num; id[Type] = INT; id[Val] = i++;
399 |           if (tk == ',') next();
400 |         }
401 |         next();
402 |       }
403 |     }
404 |     while (tk != ';' && tk != '}') {
405 |       ty = bt;
406 |       while (tk == Mul) { next(); ty = ty + PTR; }
407 |       if (tk != Id) { printf("%d: bad global declaration\n", line); return -1; }
408 |       if (id[Class]) { printf("%d: duplicate global definition\n", line); return -1; }
409 |       next();
410 |       id[Type] = ty;
411 |       if (tk == '(') { // function
412 |         id[Class] = Fun;
413 |         id[Val] = (int)(e + 1);
414 |         next(); i = 0;
415 |         while (tk != ')') {
416 |           ty = INT;
417 |           if (tk == Int) next();
418 |           else if (tk == Char) { next(); ty = CHAR; }
419 |           while (tk == Mul) { next(); ty = ty + PTR; }
420 |           if (tk != Id) { printf("%d: bad parameter declaration\n", line); return -1; }
421 |           if (id[Class] == Loc) { printf("%d: duplicate parameter definition\n", line); return -1; }
422 |           id[HClass] = id[Class]; id[Class] = Loc;
423 |           id[HType]  = id[Type];  id[Type] = ty;
424 |           id[HVal]   = id[Val];   id[Val] = i++;
425 |           next();
426 |           if (tk == ',') next();
427 |         }
428 |         next();
429 |         if (tk != '{') { printf("%d: bad function definition\n", line); return -1; }
430 |         loc = ++i;
431 |         next();
432 |         while (tk == Int || tk == Char) {
433 |           bt = (tk == Int) ? INT : CHAR;
434 |           next();
435 |           while (tk != ';') {
436 |             ty = bt;
437 |             while (tk == Mul) { next(); ty = ty + PTR; }
438 |             if (tk != Id) { printf("%d: bad local declaration\n", line); return -1; }
439 |             if (id[Class] == Loc) { printf("%d: duplicate local definition\n", line); return -1; }
440 |             id[HClass] = id[Class]; id[Class] = Loc;
441 |             id[HType]  = id[Type];  id[Type] = ty;
442 |             id[HVal]   = id[Val];   id[Val] = ++i;
443 |             next();
444 |             if (tk == ',') next();
445 |           }
446 |           next();
447 |         }
448 |         *++e = ENT; *++e = i - loc;
449 |         while (tk != '}') stmt();
450 |         *++e = LEV;
451 |         id = sym; // unwind symbol table locals
452 |         while (id[Tk]) {
453 |           if (id[Class] == Loc) {
454 |             id[Class] = id[HClass];
455 |             id[Type] = id[HType];
456 |             id[Val] = id[HVal];
457 |           }
458 |           id = id + Idsz;
459 |         }
460 |       }
461 |       else {
462 |         id[Class] = Glo;
463 |         id[Val] = (int)data;
464 |         data = data + sizeof(int);
465 |       }
466 |       if (tk == ',') next();
467 |     }
468 |     next();
469 |   }
470 | 
471 |   dl = dlopen(0, RTLD_LAZY | RTLD_GLOBAL); // RTLD_LAZY = 1
472 | 
473 |   // setup jit memory
474 |   //jitmem = mmap(0, poolsz, PROT_EXEC | PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, 0);
475 |   jitmem = mmap(0, poolsz, 7, 0x1002 | MAP_ANON, -1, 0);
476 |   if (!jitmem) { printf("could not mmap(%d) jit executable memory\n", poolsz); return -1; }
477 | 
478 |   jitmap = (char **)(jitmem + poolsz / 2);
479 | 
480 |   // first pass: emit native code
481 |   pc = text + 1; je = jitmem; line = 0;
482 |   while (pc <= e) {
483 |     i = *pc;
484 |     if (src) {
485 |         while (line < srcmap[pc - text]) {
486 |             line++; printf("% 4d | %.*s", line, linemap[line + 1] - linemap[line], linemap[line]);
487 |         }
488 |         printf("0x%05x (%p):\t%8.4s", pc - text, je,
489 |                         &"LEA ,IMM ,JMP ,JSR ,BZ  ,BNZ ,ENT ,ADJ ,LEV ,LI  ,LC  ,SI  ,SC  ,PSH ,"
490 |                          "OR  ,XOR ,AND ,EQ  ,NE  ,LT  ,GT  ,LE  ,GE  ,SHL ,SHR ,ADD ,SUB ,MUL ,DIV ,MOD ,"
491 |                          "OPEN,READ,CLOS,PRTF,MALC,MSET,MCMP,MCPY,MMAP,DOPN,DSYM,QSRT,EXIT,"[i * 5]);
492 |         if (i <= ADJ) printf(" 0x%x\n", *(pc + 1)); else printf("\n");
493 |     }
494 |     jitmap[pc - text] = je;  // for later relocation of JMP/JSR/BZ/BNZ
495 |     pc++;
496 |     if (i == LEA) {
497 |       i = 4 * *pc++; if (i < -128 || i > 127) { printf("jit: LEA out of bounds\n"); return -1; }
498 |       *(int*)je = 0x458d; je = je + 2; *je++ = i;  // leal $(4 * n)(%ebp), %eax
499 |     }
500 |     else if (i == ENT) {
501 |       i = 4 * *pc++; if (i < -128 || i > 127) { printf("jit: ENT out of bounds\n"); return -1; }
502 |       *(int *)je = 0xe58955; je = je + 3;  // push %ebp; movl %esp, %ebp
503 |       if (i > 0) { *(int *)je = 0xec83; je = je + 2; *(int*)je++ = i; } // subl $(i*4), %esp
504 |     }
505 |     else if (i == IMM) { *je++ = 0xb8; *(int *)je = *pc++; je = je + 4; } // movl $imm, %eax
506 |     else if (i == ADJ) { i = 4 * *pc++; *(int *)je = 0xc483; je = je + 2; *(int *)je = i; je++; } // addl $(n * 4), %esp
507 |     else if (i == PSH)   *(int *)je++ = 0x50;                    // push %eax
508 |     else if (i == LEV) { *(int *)je = 0xc35dec89; je = je + 4; } // mov %ebp, %esp; pop %ebp; ret
509 |     else if (i == LI)  { *(int *)je = 0x008b;     je = je + 2; } // movl (%eax), %eax
510 |     else if (i == LC)  { *(int *)je = 0x00b60f;   je = je + 3; } // movzbl (%eax), %eax
511 |     else if (i == SI)  { *(int *)je = 0x018959;   je = je + 3; } // pop %ecx; movl %eax, (%ecx)
512 |     else if (i == SC)  { *(int *)je = 0x018859;   je = je + 3; } // pop %ecx; movb %al, (%ecx)
513 |     else if (i == OR)  { *(int *)je = 0xc80959;   je = je + 3; } // pop %ecx; orl %ecx, %eax
514 |     else if (i == XOR) { *(int *)je = 0xc83159;   je = je + 3; } // pop %ecx; xorl %ecx, %eax
515 |     else if (i == AND) { *(int *)je = 0xc82159;   je = je + 3; } // pop %ecx; andl %ecx, %eax
516 |     else if (EQ <= i && i <= GE) {
517 |         *(int*)je=0x0fc13959; je = je + 4; *(int*)je=0x9866c094; // pop %ecx; cmp %ecx, %eax; sete %al; cbw; - EQ
518 |         if      (i == NE)  { *je = 0x95; } // setne %al
519 |         else if (i == LT)  { *je = 0x9c; } // setl %al
520 |         else if (i == GT)  { *je = 0x9f; } // setg %al
521 |         else if (i == LE)  { *je = 0x9e; } // setle %al
522 |         else if (i == GE)  { *je = 0x9d; } // setge %al
523 |         je=je+4; *je++=0x98;  // cwde
524 |     }
525 |     else if (i == SHL) { *(int*)je = 0xe0d39159; je = je + 4; } // pop %ecx; xchg %eax, %ecx; shl %cl, %eax
526 |     else if (i == SHR) { *(int*)je = 0xe8d39159; je = je + 4; } // pop %ecx; xchg %eax, %ecx; shr %cl, %eax
527 |     else if (i == ADD) { *(int*)je = 0xc80159;   je = je + 3; } // pop %ecx; addl %ecx, %eax
528 |     else if (i == SUB) { *(int*)je = 0xc8299159; je = je + 4; } // pop %ecx; xchg %eax, %ecx; subl %ecx, %eax
529 |     else if (i == MUL) { *(int*)je = 0xc1af0f59; je = je + 4; } // pop %ecx; imul %ecx, %eax
530 |     else if (i == DIV) { *(int*)je = 0xf9f79159; je = je + 4; } // pop %ecx; xchg %eax, %ecx; idiv %ecx, %eax
531 |     else if (i == MOD) { *(int*)je = 0xd2319159; je = je + 4; *(int *)je = 0x92f9f7; je = je + 3; }
532 |     else if (i == JMP) { ++pc; *je       = 0xe9;     je = je + 5; } // jmp <off32>
533 |     else if (i == JSR) { ++pc; *je       = 0xe8;     je = je + 5; } // call <off32>
534 |     else if (i == BZ)  { ++pc; *(int*)je = 0x840fc085; je = je + 8; } // test %eax, %eax; jz <off32>
535 |     else if (i == BNZ) { ++pc; *(int*)je = 0x850fc085; je = je + 8; } // test %eax, %eax; jnz <off32>
536 |     else if (i >= OPEN) {
537 |       if      (i == OPEN) tmp = (int)dlsym(dl, "open");
538 |       else if (i == READ) tmp = (int)dlsym(dl, "read");
539 |       else if (i == CLOS) tmp = (int)dlsym(dl, "close");
540 |       else if (i == PRTF) tmp = (int)dlsym(dl, "printf");
541 |       else if (i == MALC) tmp = (int)dlsym(dl, "malloc");
542 |       else if (i == MSET) tmp = (int)dlsym(dl, "memset");
543 |       else if (i == MCMP) tmp = (int)dlsym(dl, "memcmp");
544 |       else if (i == MCPY) tmp = (int)dlsym(dl, "memcpy");
545 |       else if (i == MMAP) tmp = (int)dlsym(dl, "mmap");
546 |       else if (i == DOPN) tmp = (int)dlsym(dl, "dlopen");
547 |       else if (i == DSYM) tmp = (int)dlsym(dl, "dlsym");
548 |       else if (i == QSRT) tmp = (int)dlsym(dl, "qsort");
549 |       else if (i == EXIT) tmp = (int)dlsym(dl, "exit");
550 | 
551 |       if (*pc++ == ADJ) { i = *pc++; } else { printf("no ADJ after native proc!\n"); exit(2); }
552 | 
553 |       *je++ = 0xb9; *(int*)je = i << 2; je = je + 4;  // movl $(4 * n), %ecx;
554 |       *(int*)je = 0xce29e689; je = je + 4; // mov %esp, %esi; sub %ecx, %esi;  -- %esi will adjust the stack
555 |       *(int*)je = 0x8302e9c1; je = je + 4; // shr $2, %ecx; and                -- alignment of %esp for OS X
556 |       *(int*)je = 0x895af0e6; je = je + 4; // $0xfffffff0, %esi; pop %edx; mov..
557 |       *(int*)je = 0xe2fc8e54; je = je + 4; // ..%edx, -4(%esi,%ecx,4); loop..  -- reversing args order
558 |       *(int*)je = 0xe8f487f9; je = je + 4; // ..<'pop' offset>; xchg %esi, %esp; call    -- saving old stack in %esi
559 |       *(int*)je = tmp - (int)(je + 4); je = je + 4; // <*tmp offset>;
560 |       *(int*)je = 0xf487; je = je + 2;     // xchg %esi, %esp  -- ADJ, back to old stack without arguments
561 |     }
562 |     else { printf("code generation failed for %d!\n", i); return -1; }
563 |   }
564 | 
565 |   // second pass, relocation
566 |   pc = text + 1;
567 |   while (pc <= e) {
568 |     je = jitmap[pc - text];
569 |     i = *pc++;
570 |     if (i == JSR || i == JMP || i == BZ || i == BNZ) {
571 |         tmp = (int)jitmap[(int *)*pc++ - text];
572 |         if      (i == JSR || i == JMP) { je = je + 1; *(int*)je = tmp - (int)(je + 4); }
573 |         else if (i == BZ  || i == BNZ) { je = je + 4; *(int*)je = tmp - (int)(je + 4); }
574 |     }
575 |     else if (i < LEV) { ++pc; }
576 |   }
577 | 
578 |   // run jitted code
579 |   pc = (int *) idmain[Val];
580 |   jitmain = (void *) jitmap[ pc - text ];
581 |   return jitmain(argv, argc); // c4 vm pushes first argument first, unlike cdecl
582 | }
583 | 


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