├── LICENSE ├── README.md ├── i686-asm ├── boot.s ├── crti.s ├── crtn.s └── paging.s ├── linker.ld ├── memory.png ├── nakefile.nim └── source ├── asmwrapper.nim ├── gdt.nim ├── idt.nim ├── irq.nim ├── isrs.nim ├── kernel.nim ├── kernel.nim.cfg ├── keyboard.nim ├── math.nim ├── memory.nim ├── merosystem.nim ├── paging.nim ├── panicoverride.nim ├── timer.nim ├── tty.nim └── vga.nim /LICENSE: -------------------------------------------------------------------------------- 1 | GNU GENERAL PUBLIC LICENSE 2 | Version 3, 29 June 2007 3 | 4 | Copyright (C) 2007 Free Software Foundation, Inc. 5 | Everyone is permitted to copy and distribute verbatim copies 6 | of this license document, but changing it is not allowed. 7 | 8 | Preamble 9 | 10 | The GNU General Public License is a free, copyleft license for 11 | software and other kinds of works. 12 | 13 | The licenses for most software and other practical works are designed 14 | to take away your freedom to share and change the works. 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Interpretation of Sections 15 and 16. 613 | 614 | If the disclaimer of warranty and limitation of liability provided 615 | above cannot be given local legal effect according to their terms, 616 | reviewing courts shall apply local law that most closely approximates 617 | an absolute waiver of all civil liability in connection with the 618 | Program, unless a warranty or assumption of liability accompanies a 619 | copy of the Program in return for a fee. 620 | 621 | END OF TERMS AND CONDITIONS 622 | 623 | How to Apply These Terms to Your New Programs 624 | 625 | If you develop a new program, and you want it to be of the greatest 626 | possible use to the public, the best way to achieve this is to make it 627 | free software which everyone can redistribute and change under these terms. 628 | 629 | To do so, attach the following notices to the program. It is safest 630 | to attach them to the start of each source file to most effectively 631 | state the exclusion of warranty; and each file should have at least 632 | the "copyright" line and a pointer to where the full notice is found. 633 | 634 | 635 | Copyright (C) 636 | 637 | This program is free software: you can redistribute it and/or modify 638 | it under the terms of the GNU General Public License as published by 639 | the Free Software Foundation, either version 3 of the License, or 640 | (at your option) any later version. 641 | 642 | This program is distributed in the hope that it will be useful, 643 | but WITHOUT ANY WARRANTY; without even the implied warranty of 644 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 645 | GNU General Public License for more details. 646 | 647 | You should have received a copy of the GNU General Public License 648 | along with this program. If not, see . 649 | 650 | Also add information on how to contact you by electronic and paper mail. 651 | 652 | If the program does terminal interaction, make it output a short 653 | notice like this when it starts in an interactive mode: 654 | 655 | Copyright (C) 656 | This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'. 657 | This is free software, and you are welcome to redistribute it 658 | under certain conditions; type `show c' for details. 659 | 660 | The hypothetical commands `show w' and `show c' should show the appropriate 661 | parts of the General Public License. Of course, your program's commands 662 | might be different; for a GUI interface, you would use an "about box". 663 | 664 | You should also get your employer (if you work as a programmer) or school, 665 | if any, to sign a "copyright disclaimer" for the program, if necessary. 666 | For more information on this, and how to apply and follow the GNU GPL, see 667 | . 668 | 669 | The GNU General Public License does not permit incorporating your program 670 | into proprietary programs. If your program is a subroutine library, you 671 | may consider it more useful to permit linking proprietary applications with 672 | the library. If this is what you want to do, use the GNU Lesser General 673 | Public License instead of this License. But first, please read 674 | . 675 | -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | # Mero 2 | Kernel in nim 3 | 4 | Heavily based off of [nimkernel](https://github.com/dom96/nimkernel) and [the osdev wiki](http://wiki.osdev.org/) 5 | 6 | ![Simple demo is simple](https://i.gyazo.com/fddee0db73bb8e9e65f8d55e9a9e8cc9.png) 7 | -------------------------------------------------------------------------------- /i686-asm/boot.s: -------------------------------------------------------------------------------- 1 | ; This is the kernel's entry point. We could either call main here, 2 | ; or we can use this to setup the stack or other nice stuff, like 3 | ; perhaps setting up the GDT and segments. Please note that interrupts 4 | ; are disabled at this point: More on interrupts later! 5 | [BITS 32] 6 | global start 7 | start: 8 | mov esp, _sys_stack ; This points the stack to our new stack area 9 | jmp stublet 10 | 11 | ; This part MUST be 4byte aligned, so we solve that issue using 'ALIGN 4' 12 | ALIGN 4 13 | mboot: 14 | ; Multiboot macros to make a few lines later more readable 15 | MULTIBOOT_PAGE_ALIGN equ 1<<0 16 | MULTIBOOT_MEMORY_INFO equ 1<<1 17 | MULTIBOOT_AOUT_KLUDGE equ 1<<16 18 | MULTIBOOT_HEADER_MAGIC equ 0x1BADB002 19 | MULTIBOOT_HEADER_FLAGS equ MULTIBOOT_PAGE_ALIGN | MULTIBOOT_MEMORY_INFO | MULTIBOOT_AOUT_KLUDGE 20 | MULTIBOOT_CHECKSUM equ -(MULTIBOOT_HEADER_MAGIC + MULTIBOOT_HEADER_FLAGS) 21 | EXTERN code, bss, end 22 | 23 | ; This is the GRUB Multiboot header. A boot signature 24 | dd MULTIBOOT_HEADER_MAGIC 25 | dd MULTIBOOT_HEADER_FLAGS 26 | dd MULTIBOOT_CHECKSUM 27 | 28 | ; AOUT kludge - must be physical addresses. Make a note of these: 29 | ; The linker script fills in the data for these ones! 30 | dd mboot 31 | dd code 32 | dd bss 33 | dd end 34 | dd start 35 | 36 | ; This is an endless loop here. Make a note of this: Later on, we 37 | ; will insert an 'extern _main', followed by 'call _main', right 38 | ; before the 'jmp $'. 39 | stublet: 40 | extern kernel_early 41 | extern kernel_main 42 | extern _init 43 | cli 44 | call kernel_early 45 | call _init 46 | push ebx 47 | call kernel_main 48 | jmp $ 49 | 50 | 51 | ; Shortly we will add code for loading the GDT right here! 52 | ; This will set up our new segment registers. We need to do 53 | ; something special in order to set CS. We do what is called a 54 | ; far jump. A jump that includes a segment as well as an offset. 55 | ; This is declared in C as 'extern void gdt_flush();' 56 | global gdt_flush ; Allows the C code to link to this 57 | extern gp ; Says that '_gp' is in another file 58 | gdt_flush: 59 | lgdt [gp] ; Load the GDT with our '_gp' which is a special pointer 60 | mov ax, 0x10 ; 0x10 is the offset in the GDT to our data segment 61 | mov ds, ax 62 | mov es, ax 63 | mov fs, ax 64 | mov gs, ax 65 | mov ss, ax 66 | jmp 0x08:flush2 ; 0x08 is the offset to our code segment: Far jump! 67 | flush2: 68 | ret ; Returns back to the C code! 69 | 70 | ; Loads the IDT defined in '_idtp' into the processor. 71 | ; This is declared in C as 'extern void idt_load();' 72 | global idt_load 73 | extern idtp 74 | idt_load: 75 | lidt [idtp] 76 | ret 77 | 78 | global isr0 79 | global isr1 80 | global isr2 81 | global isr3 82 | global isr4 83 | global isr5 84 | global isr6 85 | global isr7 86 | global isr8 87 | global isr9 88 | global isr10 89 | global isr11 90 | global isr12 91 | global isr13 92 | global isr14 93 | global isr15 94 | global isr16 95 | global isr17 96 | global isr18 97 | global isr19 98 | global isr20 99 | global isr21 100 | global isr22 101 | global isr23 102 | global isr24 103 | global isr25 104 | global isr26 105 | global isr27 106 | global isr28 107 | global isr29 108 | global isr30 109 | global isr31 110 | ; 0: Divide By Zero Exception 111 | isr0: 112 | push byte 0 113 | push byte 0 114 | jmp isr_common_stub 115 | 116 | ; 1: Debug Exception 117 | isr1: 118 | push byte 0 119 | push byte 1 120 | jmp isr_common_stub 121 | 122 | ; 2: Non Maskable Interrupt Exception 123 | isr2: 124 | push byte 0 125 | push byte 2 126 | jmp isr_common_stub 127 | 128 | ; 3: Int 3 Exception 129 | isr3: 130 | push byte 0 131 | push byte 3 132 | jmp isr_common_stub 133 | 134 | ; 4: INTO Exception 135 | isr4: 136 | push byte 0 137 | push byte 4 138 | jmp isr_common_stub 139 | 140 | ; 5: Out of Bounds Exception 141 | isr5: 142 | push byte 0 143 | push byte 5 144 | jmp isr_common_stub 145 | 146 | ; 6: Invalid Opcode Exception 147 | isr6: 148 | push byte 0 149 | push byte 6 150 | jmp isr_common_stub 151 | 152 | ; 7: Coprocessor Not Available Exception 153 | isr7: 154 | push byte 0 155 | push byte 7 156 | jmp isr_common_stub 157 | 158 | ; 8: Double Fault Exception (With Error Code!) 159 | isr8: 160 | push byte 8 161 | jmp isr_common_stub 162 | 163 | ; 9: Coprocessor Segment Overrun Exception 164 | isr9: 165 | push byte 0 166 | push byte 9 167 | jmp isr_common_stub 168 | 169 | ; 10: Bad TSS Exception (With Error Code!) 170 | isr10: 171 | push byte 10 172 | jmp isr_common_stub 173 | 174 | ; 11: Segment Not Present Exception (With Error Code!) 175 | isr11: 176 | push byte 11 177 | jmp isr_common_stub 178 | 179 | ; 12: Stack Fault Exception (With Error Code!) 180 | isr12: 181 | push byte 12 182 | jmp isr_common_stub 183 | 184 | ; 13: General Protection Fault Exception (With Error Code!) 185 | isr13: 186 | push byte 13 187 | jmp isr_common_stub 188 | 189 | ; 14: Page Fault Exception (With Error Code!) 190 | isr14: 191 | push byte 14 192 | jmp isr_common_stub 193 | 194 | ; 15: Reserved Exception 195 | isr15: 196 | push byte 0 197 | push byte 15 198 | jmp isr_common_stub 199 | 200 | ; 16: Floating Point Exception 201 | isr16: 202 | push byte 0 203 | push byte 16 204 | jmp isr_common_stub 205 | 206 | ; 17: Alignment Check Exception 207 | isr17: 208 | push byte 0 209 | push byte 17 210 | jmp isr_common_stub 211 | 212 | ; 18: Machine Check Exception 213 | isr18: 214 | push byte 0 215 | push byte 18 216 | jmp isr_common_stub 217 | 218 | ; 19: Reserved 219 | isr19: 220 | push byte 0 221 | push byte 19 222 | jmp isr_common_stub 223 | 224 | ; 20: Reserved 225 | isr20: 226 | push byte 0 227 | push byte 20 228 | jmp isr_common_stub 229 | 230 | ; 21: Reserved 231 | isr21: 232 | push byte 0 233 | push byte 21 234 | jmp isr_common_stub 235 | 236 | ; 22: Reserved 237 | isr22: 238 | push byte 0 239 | push byte 22 240 | jmp isr_common_stub 241 | 242 | ; 23: Reserved 243 | isr23: 244 | push byte 0 245 | push byte 23 246 | jmp isr_common_stub 247 | 248 | ; 24: Reserved 249 | isr24: 250 | push byte 0 251 | push byte 24 252 | jmp isr_common_stub 253 | 254 | ; 25: Reserved 255 | isr25: 256 | push byte 0 257 | push byte 25 258 | jmp isr_common_stub 259 | 260 | ; 26: Reserved 261 | isr26: 262 | push byte 0 263 | push byte 26 264 | jmp isr_common_stub 265 | 266 | ; 27: Reserved 267 | isr27: 268 | push byte 0 269 | push byte 27 270 | jmp isr_common_stub 271 | 272 | ; 28: Reserved 273 | isr28: 274 | push byte 0 275 | push byte 28 276 | jmp isr_common_stub 277 | 278 | ; 29: Reserved 279 | isr29: 280 | push byte 0 281 | push byte 29 282 | jmp isr_common_stub 283 | 284 | ; 30: Reserved 285 | isr30: 286 | push byte 0 287 | push byte 30 288 | jmp isr_common_stub 289 | 290 | ; 31: Reserved 291 | isr31: 292 | push byte 0 293 | push byte 31 294 | jmp isr_common_stub 295 | 296 | 297 | ; We call a C function in here. We need to let the assembler know 298 | ; that '_fault_handler' exists in another file 299 | extern fault_handler 300 | 301 | ; This is our common ISR stub. It saves the processor state, sets 302 | ; up for kernel mode segments, calls the C-level fault handler, 303 | ; and finally restores the stack frame. 304 | isr_common_stub: 305 | pusha 306 | push ds 307 | push es 308 | push fs 309 | push gs 310 | mov ax, 0x10 311 | mov ds, ax 312 | mov es, ax 313 | mov fs, ax 314 | mov gs, ax 315 | mov eax, esp 316 | push eax 317 | mov eax, fault_handler 318 | call eax 319 | pop eax 320 | pop gs 321 | pop fs 322 | pop es 323 | pop ds 324 | popa 325 | add esp, 8 326 | iret 327 | 328 | global irq0 329 | global irq1 330 | global irq2 331 | global irq3 332 | global irq4 333 | global irq5 334 | global irq6 335 | global irq7 336 | global irq8 337 | global irq9 338 | global irq10 339 | global irq11 340 | global irq12 341 | global irq13 342 | global irq14 343 | global irq15 344 | 345 | ; 32: IRQ0 346 | irq0: 347 | push byte 0 348 | push byte 32 349 | jmp irq_common_stub 350 | 351 | ; 33: IRQ1 352 | irq1: 353 | push byte 0 354 | push byte 33 355 | jmp irq_common_stub 356 | 357 | ; 34: IRQ2 358 | irq2: 359 | push byte 0 360 | push byte 34 361 | jmp irq_common_stub 362 | 363 | ; 35: IRQ3 364 | irq3: 365 | push byte 0 366 | push byte 35 367 | jmp irq_common_stub 368 | 369 | ; 36: IRQ4 370 | irq4: 371 | push byte 0 372 | push byte 36 373 | jmp irq_common_stub 374 | 375 | ; 37: IRQ5 376 | irq5: 377 | push byte 0 378 | push byte 37 379 | jmp irq_common_stub 380 | 381 | ; 38: IRQ6 382 | irq6: 383 | push byte 0 384 | push byte 38 385 | jmp irq_common_stub 386 | 387 | ; 39: IRQ7 388 | irq7: 389 | push byte 0 390 | push byte 39 391 | jmp irq_common_stub 392 | 393 | ; 40: IRQ8 394 | irq8: 395 | push byte 0 396 | push byte 40 397 | jmp irq_common_stub 398 | 399 | ; 41: IRQ9 400 | irq9: 401 | push byte 0 402 | push byte 41 403 | jmp irq_common_stub 404 | 405 | ; 42: IRQ10 406 | irq10: 407 | push byte 0 408 | push byte 42 409 | jmp irq_common_stub 410 | 411 | ; 43: IRQ11 412 | irq11: 413 | push byte 0 414 | push byte 43 415 | jmp irq_common_stub 416 | 417 | ; 44: IRQ12 418 | irq12: 419 | push byte 0 420 | push byte 44 421 | jmp irq_common_stub 422 | 423 | ; 45: IRQ13 424 | irq13: 425 | push byte 0 426 | push byte 45 427 | jmp irq_common_stub 428 | 429 | ; 46: IRQ14 430 | irq14: 431 | push byte 0 432 | push byte 46 433 | jmp irq_common_stub 434 | 435 | ; 47: IRQ15 436 | irq15: 437 | push byte 0 438 | push byte 47 439 | jmp irq_common_stub 440 | 441 | extern irq_handler 442 | 443 | irq_common_stub: 444 | pusha 445 | push ds 446 | push es 447 | push fs 448 | push gs 449 | 450 | mov ax, 0x10 451 | mov ds, ax 452 | mov es, ax 453 | mov fs, ax 454 | mov gs, ax 455 | mov eax, esp 456 | 457 | push eax 458 | mov eax, irq_handler 459 | call eax 460 | pop eax 461 | 462 | pop gs 463 | pop fs 464 | pop es 465 | pop ds 466 | popa 467 | add esp, 8 468 | iret 469 | 470 | ; In just a few pages in this tutorial, we will add our Interrupt 471 | ; Service Routines (ISRs) right here! 472 | 473 | ; Here is the definition of our BSS section. Right now, we'll use 474 | ; it just to store the stack. Remember that a stack actually grows 475 | ; downwards, so we declare the size of the data before declaring 476 | ; the identifier '_sys_stack' 477 | SECTION .bss 478 | resb 8192 ; This reserves 8KBytes of memory here 479 | _sys_stack: 480 | -------------------------------------------------------------------------------- /i686-asm/crti.s: -------------------------------------------------------------------------------- 1 | .section .init 2 | .global _init 3 | .type _init, @function 4 | _init: 5 | push %ebp 6 | movl %esp, %ebp 7 | /* gcc will nicely put the contents of crtbegin.o's .init section here. */ 8 | 9 | .section .fini 10 | .global _fini 11 | .type _fini, @function 12 | _fini: 13 | push %ebp 14 | movl %esp, %ebp 15 | /* gcc will nicely put the contents of crtbegin.o's .fini section here. */ 16 | -------------------------------------------------------------------------------- /i686-asm/crtn.s: -------------------------------------------------------------------------------- 1 | .section .init 2 | /* gcc will nicely put the contents of crtend.o's .init section here. */ 3 | popl %ebp 4 | ret 5 | 6 | .section .fini 7 | /* gcc will nicely put the contents of crtend.o's .fini section here. */ 8 | popl %ebp 9 | ret 10 | -------------------------------------------------------------------------------- /i686-asm/paging.s: -------------------------------------------------------------------------------- 1 | .text 2 | .globl loadPageDirectory 3 | loadPageDirectory: 4 | push %ebp 5 | mov %esp, %ebp 6 | mov 8(%esp), %eax 7 | mov %eax, %cr3 8 | mov %ebp, %esp 9 | pop %ebp 10 | ret 11 | 12 | .text 13 | .globl enablePaging 14 | enablePaging: 15 | push %ebp 16 | mov %esp, %ebp 17 | mov %cr0, %eax 18 | or $0x80000000, %eax 19 | mov %eax, %cr0 20 | mov %ebp, %esp 21 | pop %ebp 22 | ret 23 | -------------------------------------------------------------------------------- /linker.ld: -------------------------------------------------------------------------------- 1 | OUTPUT_FORMAT("binary") 2 | ENTRY(start) 3 | phys = 0x00100000; 4 | SECTIONS 5 | { 6 | kernel_start = .; 7 | .text phys : AT(phys) { 8 | code = .; 9 | *(.text) 10 | *(.rodata) 11 | . = ALIGN(4096); 12 | } 13 | .data : AT(phys + (data - code)) 14 | { 15 | data = .; 16 | *(.data) 17 | . = ALIGN(4096); 18 | } 19 | .bss : AT(phys + (bss - code)) 20 | { 21 | bss = .; 22 | *(.bss) 23 | . = ALIGN(4096); 24 | } 25 | end = .; 26 | } 27 | -------------------------------------------------------------------------------- /memory.png: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/samanthadoran/Mero/78dcc32c4c4f92c64245de98f82a26a58e05984f/memory.png -------------------------------------------------------------------------------- /nakefile.nim: -------------------------------------------------------------------------------- 1 | import nake 2 | import os 3 | 4 | #Thank yout to https://github.com/dom96/nimkernel for the example of how to set this up! 5 | 6 | const 7 | CC = "i686-elf-gcc" 8 | asmC = "nasm -felf32" 9 | 10 | task "clean", "Removes build files.": 11 | removeFile("boot.o") 12 | removeFile("interrupts.o") 13 | removeFile("gdt.o") 14 | removeFile("crti.o") 15 | removeFile("crtn.o") 16 | removeFile("paging.o") 17 | removeFile("interrupt.o") 18 | removeFile("mero.bin") 19 | removeDir("source/nimcache") 20 | removeDir("nimcache") 21 | echo "Done." 22 | 23 | task "build", "Builds the operating system.": 24 | echo "Compiling..." 25 | direShell "nim c -d:release --gcc.exe:$1 source/kernel" % CC 26 | 27 | echo "Assembling..." 28 | direShell asmc, "i686-asm/boot.s -o boot.o" 29 | direShell "i686-elf-as i686-asm/paging.s -o paging.o" 30 | direShell "i686-elf-as i686-asm/crtn.s -o crtn.o" 31 | direShell "i686-elf-as i686-asm/crti.s -o crti.o" 32 | 33 | echo "Linking..." 34 | 35 | direShell CC, "-T linker.ld -o mero.bin -ffreestanding -O2 -nostdlib *.o source/nimcache/*.o" 36 | 37 | task "run-qemu", "Runs the operating system using QEMU.": 38 | #if not existsFile("mero.bin"): runTask("build") 39 | runTask("build") 40 | direShell "qemu-system-i386 -kernel mero.bin" 41 | 42 | task "run-bochs", "Runs the operating system using bochs.": 43 | runTask("build") 44 | echo("Updating image...") 45 | direShell "sudo losetup /dev/loop0 floppy.img" 46 | direShell "sudo mount /dev/loop0 /mnt" 47 | direShell "sudo cp mero.bin /mnt/kernel" 48 | direShell "sudo umount /dev/loop0" 49 | direShell "sudo losetup -d /dev/loop0" 50 | 51 | echo("Running bochs...") 52 | direShell "sudo /sbin/losetup /dev/loop0 floppy.img" 53 | direShell "sudo bochs -q -f bochsrc.txt" 54 | direShell "sudo /sbin/losetup -d /dev/loop0" 55 | -------------------------------------------------------------------------------- /source/asmwrapper.nim: -------------------------------------------------------------------------------- 1 | proc outb*(port: uint16, value: uint8) = 2 | {.emit: """ 3 | __asm__ __volatile__ ("outb %1, %0" : : "dN" (`port`), "a" (`value`)); 4 | """} 5 | 6 | proc inb*(port: uint16): uint8 = 7 | asm """ 8 | inb %%dx, %%al 9 | :"=a" (`result`) 10 | :"d" (`port`) 11 | """ 12 | -------------------------------------------------------------------------------- /source/gdt.nim: -------------------------------------------------------------------------------- 1 | type 2 | gdt_entry = object {.packed.} 3 | limit_low*: uint16 4 | base_low*: uint16 5 | base_middle*: uint8 6 | access*: uint8 7 | granularity*: uint8 8 | base_high*: uint8 9 | 10 | gdt_ptr = object {.packed.} 11 | limit*: uint16 12 | base*: uint32 13 | 14 | var gdt: array[0..2, gdt_entry] 15 | var gp {.exportc.}: gdt_ptr 16 | 17 | #Declared in boot.s 18 | proc gdtFlush() {.importc: "gdt_flush".} 19 | 20 | proc gdtSetGate(num: int, base: uint32, limit: uint32, access: uint8, gran: uint8) = 21 | gdt[num].base_low = base and 0xFFFF 22 | gdt[num].base_middle = (base shr 16) and 0xFF 23 | gdt[num].base_high = (base shr 24) and 0xFF 24 | 25 | gdt[num].limit_low = limit and 0xFFFF 26 | gdt[num].granularity = (limit shr 16) and 0x0F 27 | 28 | gdt[num].granularity = gdt[num].granularity or (gran and 0xF0) 29 | gdt[num].access = access 30 | 31 | proc gdtInstall*() = 32 | #Set the gdt pointer and limit 33 | gp.limit = cast[uint16]((sizeof(gdt_entry) * 3) - 1) 34 | gp.base = cast[uint32](addr(gdt)) 35 | 36 | #Init null descriptor 37 | gdtSetGate(0, 0, 0, 0, 0) 38 | 39 | #Init code segment 40 | gdtSetGate(1, 0, cast[uint32](0xFFFFFFFF), 0x9A, 0xCF) 41 | 42 | #Init data segment 43 | gdtSetGate(2, 0, cast[uint32](0xFFFFFFFF), 0x92, 0xCF) 44 | 45 | #Tell the cpu about our GDT 46 | gdtFlush() 47 | -------------------------------------------------------------------------------- /source/idt.nim: -------------------------------------------------------------------------------- 1 | import memory 2 | 3 | type 4 | idt_entry = object {.packed.} 5 | base_low*: uint16 6 | sel*: uint16 7 | always0*: uint8 8 | flags*: uint8 9 | base_high*: uint16 10 | 11 | idt_ptr = object {.packed} 12 | limit*: uint16 13 | base*: uint32 14 | 15 | var idt: array[0..255, idt_entry] 16 | var idtp {.exportc.}: idt_ptr 17 | 18 | #Declared in boot.s 19 | proc idtLoad() {.importc: "idt_load".} 20 | 21 | proc idtSetGate*(num: uint8, base: uint32, sel: uint16, flags: uint8) = 22 | idt[num].base_low = base and 0xFFFF 23 | idt[num].base_high = (base shr 16) and 0xFFFF 24 | 25 | idt[num].sel = sel 26 | idt[num].always0 = 0 27 | idt[num].flags = flags 28 | 29 | proc idtInstall*() = 30 | #Set the limit and base 31 | idtp.limit = cast[uint16](sizeof(idt) * 256) - 1 32 | idtp.base = cast[uint32](addr(idt)) 33 | 34 | var ptr_idt: ptr uint8 = cast[ptr uint8](addr(idt)) 35 | memset(ptr_idt, 0, cast[uint32](sizeof(idt_entry) * 256)) 36 | 37 | #ISRs go here 38 | 39 | #Tell the cpu about our idt 40 | idtLoad() 41 | -------------------------------------------------------------------------------- /source/irq.nim: -------------------------------------------------------------------------------- 1 | import merosystem 2 | import memory 3 | import tty 4 | 5 | {.emit: """ 6 | extern void irq0(); 7 | extern void irq1(); 8 | extern void irq2(); 9 | extern void irq3(); 10 | extern void irq4(); 11 | extern void irq5(); 12 | extern void irq6(); 13 | extern void irq7(); 14 | extern void irq8(); 15 | extern void irq9(); 16 | extern void irq10(); 17 | extern void irq11(); 18 | extern void irq12(); 19 | extern void irq13(); 20 | extern void irq14(); 21 | extern void irq15(); 22 | """} 23 | 24 | proc getIrq(i: int): uint32 = 25 | #Get the address of an irq 26 | {.emit: """ 27 | switch(`i`) { 28 | case 0: 29 | `result` = irq0; 30 | break; 31 | case 1: 32 | `result` = irq1; 33 | break; 34 | case 2: 35 | `result` = irq2; 36 | break; 37 | case 3: 38 | `result` = irq3; 39 | break; 40 | case 4: 41 | `result` = irq4; 42 | break; 43 | case 5: 44 | `result` = irq5; 45 | break; 46 | case 6: 47 | `result` = irq6; 48 | break; 49 | case 7: 50 | `result` = irq7; 51 | break; 52 | case 8: 53 | `result` = irq8; 54 | break; 55 | case 9: 56 | `result` = irq9; 57 | break; 58 | case 10: 59 | `result` = irq10; 60 | break; 61 | case 11: 62 | `result` = irq11; 63 | break; 64 | case 12: 65 | `result` = irq12; 66 | break; 67 | case 13: 68 | `result` = irq13; 69 | break; 70 | case 14: 71 | `result` = irq14; 72 | break; 73 | case 15: 74 | `result` = irq15; 75 | break; 76 | } 77 | """} 78 | 79 | #Store handlers for various irqs 80 | var irq_routines: array[0..15, proc(regs: ptr registers)] 81 | 82 | proc installHandler*(irq: int, handler: proc(r: ptr registers) = nil){.exportc.} = 83 | #Add a handler.. 84 | {.emit: """ 85 | `irq_routines`[`irq`] = `handler`; 86 | """} 87 | 88 | proc uninstallHandler*(irq: int) = 89 | #Remove handler 90 | irq_routines[irq] = nil 91 | 92 | proc irqRemap() = 93 | #Prevent irqs from overlapping on PIC 94 | outb(0x20, 0x11) 95 | outb(0xA0, 0x11) 96 | outb(0x21, 0x20) 97 | outb(0xA1, 0x28) 98 | outb(0x21, 0x04) 99 | outb(0xA1, 0x02) 100 | outb(0x21, 0x01) 101 | outb(0xA1, 0x01) 102 | outb(0x21, 0x00) 103 | outb(0xA1, 0x00) 104 | 105 | proc irqInstall*() = 106 | #Lazily do this instead of memset 107 | for i in 0..15: 108 | uninstallHandler(i) 109 | 110 | #Remove conflicts with IRQ 0 - IRQ 8 111 | irqRemap() 112 | for i in 0..15: 113 | idtSetGate(cast[uint8](32 + i), getIrq(i), cast[uint16](0x08), cast[uint8](0x8E)) 114 | 115 | proc irqHandler*(regs: ptr registers) {.exportc: "irq_handler"} = 116 | #Handle various irqs 117 | 118 | #Subtract by 32 to take into account we remapped 119 | let irqIndex: uint32 = (regs.int_no) - 32 120 | 121 | #DO NOT DELETE NOINIT 122 | var handler{.noinit.}: proc(regs: ptr registers) = irq_routines[irqIndex] 123 | 124 | #If we have a handler, use it 125 | if handler != nil: 126 | handler(regs) 127 | 128 | #If the int_no we got is above 39, send a response to the slave pic on 0xA0 129 | if irqIndex + 32 >= cast[uint32](40): 130 | outb(0xA0, 0x20) 131 | 132 | #Either way, send a response to the master pic 133 | outb(0x20, 0x20) 134 | -------------------------------------------------------------------------------- /source/isrs.nim: -------------------------------------------------------------------------------- 1 | import merosystem, tty 2 | 3 | #cstrings for now because nim strings are apparently a pain 4 | var exceptionMessages {.noinit.}: array[0..31, cstring] 5 | 6 | {.emit: """ 7 | extern void isr0(); 8 | extern void isr1(); 9 | extern void isr2(); 10 | extern void isr3(); 11 | extern void isr4(); 12 | extern void isr5(); 13 | extern void isr6(); 14 | extern void isr7(); 15 | extern void isr8(); 16 | extern void isr9(); 17 | extern void isr10(); 18 | extern void isr11(); 19 | extern void isr12(); 20 | extern void isr13(); 21 | extern void isr14(); 22 | extern void isr15(); 23 | extern void isr16(); 24 | extern void isr17(); 25 | extern void isr18(); 26 | extern void isr19(); 27 | extern void isr20(); 28 | extern void isr21(); 29 | extern void isr22(); 30 | extern void isr23(); 31 | extern void isr24(); 32 | extern void isr25(); 33 | extern void isr26(); 34 | extern void isr27(); 35 | extern void isr28(); 36 | extern void isr29(); 37 | extern void isr30(); 38 | extern void isr31(); 39 | """} 40 | 41 | proc getIsr(i: int): uint32 = 42 | {.emit: """ 43 | switch(`i`) { 44 | case 0: 45 | `result` = isr0; 46 | break; 47 | case 1: 48 | `result` = isr1; 49 | break; 50 | case 2: 51 | `result` = isr2; 52 | break; 53 | case 3: 54 | `result` = isr3; 55 | break; 56 | case 4: 57 | `result` = isr4; 58 | break; 59 | case 5: 60 | `result` = isr5; 61 | break; 62 | case 6: 63 | `result` = isr6; 64 | break; 65 | case 7: 66 | `result` = isr7; 67 | break; 68 | case 8: 69 | `result` = isr8; 70 | break; 71 | case 9: 72 | `result` = isr9; 73 | break; 74 | case 10: 75 | `result` = isr10; 76 | break; 77 | case 11: 78 | `result` = isr11; 79 | break; 80 | case 12: 81 | `result` = isr12; 82 | break; 83 | case 13: 84 | `result` = isr13; 85 | break; 86 | case 14: 87 | `result` = isr14; 88 | break; 89 | case 15: 90 | `result` = isr15; 91 | break; 92 | case 16: 93 | `result` = isr16; 94 | break; 95 | case 17: 96 | `result` = isr17; 97 | break; 98 | case 18: 99 | `result` = isr18; 100 | break; 101 | case 19: 102 | `result` = isr19; 103 | break; 104 | case 20: 105 | `result` = isr20; 106 | break; 107 | case 21: 108 | `result` = isr21; 109 | break; 110 | case 22: 111 | `result` = isr22; 112 | break; 113 | case 23: 114 | `result` = isr23; 115 | break; 116 | case 24: 117 | `result` = isr24; 118 | break; 119 | case 25: 120 | `result` = isr25; 121 | break; 122 | case 26: 123 | `result` = isr26; 124 | break; 125 | case 27: 126 | `result` = isr27; 127 | break; 128 | case 28: 129 | `result` = isr28; 130 | break; 131 | case 29: 132 | `result` = isr29; 133 | break; 134 | case 30: 135 | `result` = isr30; 136 | break; 137 | case 31: 138 | `result` = isr31; 139 | } 140 | """} 141 | 142 | #TODO: Write copyString or genericAssign 143 | 144 | proc isrsInstall*() = 145 | for i in 0..31: 146 | idtSetGate(cast[uint8](i), getIsr(i), 0x08, 0x8E) 147 | exceptionMessages[0] = "Division by zero!\0" 148 | exceptionMessages[1] = "Debug!\0" 149 | exceptionMessages[2] = "Non maskable interrupt!\0" 150 | exceptionMessages[3] = "INT 3!\0" 151 | exceptionMessages[4] = "INTO!\0" 152 | exceptionMessages[5] = "Out of Bounds!\0" 153 | exceptionMessages[6] = "Bad opcode!\0" 154 | exceptionMessages[7] = "Co-processor unavailable!\0" 155 | exceptionMessages[8] = "Double Fault!\0" 156 | exceptionMessages[9] = "Co-processor segment overrun!\0" 157 | exceptionMessages[10] = "Bad TSS!\0" 158 | exceptionMessages[11] = "Segment not present!\0" 159 | exceptionMessages[12] = "Stack fault!\0" 160 | exceptionMessages[13] = "General Protection Fault!\0" 161 | exceptionMessages[14] = "Page fault!\0" 162 | exceptionMessages[15] = "Reserved!\0" 163 | exceptionMessages[16] = "Floating point exception!\0" 164 | exceptionMessages[17] = "Alignment Check!\0" 165 | exceptionMessages[18] = "Machine Check!\0" 166 | exceptionMessages[19] = "Reserved!\0" 167 | exceptionMessages[20] = "Reserved!\0" 168 | exceptionMessages[21] = "Reserved!\0" 169 | exceptionMessages[22] = "Reserved!\0" 170 | exceptionMessages[23] = "Reserved!\0" 171 | exceptionMessages[24] = "Reserved!\0" 172 | exceptionMessages[25] = "Reserved!\0" 173 | exceptionMessages[26] = "Reserved!\0" 174 | exceptionMessages[27] = "Reserved!\0" 175 | exceptionMessages[28] = "Reserved!\0" 176 | exceptionMessages[29] = "Reserved!\0" 177 | exceptionMessages[30] = "Reserved!\0" 178 | exceptionMessages[31] = "Reserved!\0" 179 | 180 | proc fault_handler(regs: ptr registers){.exportc.} = 181 | #Handle isr 182 | 183 | #If it's an exception... 184 | if regs.int_no < 32: 185 | #Halt and notify the user 186 | terminalWrite("\n================================================================================") 187 | terminalWrite("Got exception ") 188 | terminalWriteDecimal(regs.int_no) 189 | terminalWrite(": ") 190 | terminalWrite(exceptionMessages[regs.int_no]) 191 | terminalWrite("\n") 192 | terminalWrite("================================================================================") 193 | writeRegisters(regs) 194 | panic("EXCEPTION!!!!") 195 | -------------------------------------------------------------------------------- /source/kernel.nim: -------------------------------------------------------------------------------- 1 | import tty 2 | import merosystem, isrs, irq, math 3 | import timer, keyboard 4 | import paging 5 | 6 | #TODO: This is out of date??? 7 | discard """ 8 | The multiboot spec from: https://www.gnu.org/software/grub/manual/multiboot/multiboot.html 9 | follows for reference. 10 | The layout of the Multiboot header must be as follows: 11 | 12 | Offset Type Field Name Note 13 | 0 u32 magic required 14 | 4 u32 flags required 15 | 8 u32 checksum required 16 | 12 u32 header_addr if flags[16] is set 17 | 16 u32 load_addr if flags[16] is set 18 | 20 u32 load_end_addr if flags[16] is set 19 | 24 u32 bss_end_addr if flags[16] is set 20 | 28 u32 entry_addr if flags[16] is set 21 | 32 u32 mode_type if flags[2] is set 22 | 36 u32 width if flags[2] is set 23 | 40 u32 height if flags[2] is set 24 | 44 u32 depth if flags[2] is set 25 | """ 26 | 27 | type 28 | TMultiboot_header = object 29 | magic: uint32 30 | flags: uint32 31 | checksum: uint32 32 | headerAddress: uint32 33 | loadAddress: uint32 34 | loadEndAddress: uint32 35 | bssEndAddress: uint32 36 | entryAddress: uint32 37 | modeType: uint32 38 | width: uint32 39 | height: uint32 40 | depth: uint32 41 | 42 | PMultiboot_header = ptr TMultiboot_header 43 | 44 | proc kernel_early() {.exportc.} = 45 | #Things we need to happen before everything else. 46 | gdtInstall() 47 | idtInstall() 48 | isrsInstall() 49 | irqInstall() 50 | 51 | #Don't do anything serious until all tables are initialized. 52 | terminalInitialize() 53 | terminalWrite("Initialized the terminal...\n") 54 | 55 | #Malloc and free 56 | allocInstall() 57 | terminalWrite("Allocation systems initialized...\n") 58 | 59 | #Let's enable paging 60 | initPaging() 61 | terminalWrite("Paging initialized...\n") 62 | 63 | #Some handlers.. 64 | keyboardInstall() 65 | timerInstall() 66 | terminalWrite("Default handlers installed...\n") 67 | 68 | #Once we're done, we can safely enable hardware maskable interrupts 69 | {.emit: """ 70 | __asm__ __volatile__ ("sti"); 71 | """} 72 | 73 | proc kernel_main(pmbh: PMultiboot_header) {.exportc noReturn.} = 74 | terminalWrite("Hello, world!\n") 75 | terminalSetColor(makeVGAAttribute(LightGreen, Green)) 76 | terminalWrite("Testing colors...\n") 77 | 78 | terminalSetColor(makeVGAAttribute(Green, Black)) 79 | terminalWrite("Testing decimal writing with 8675309: ") 80 | terminalWriteDecimal(8675309) 81 | terminalWrite("\n") 82 | 83 | terminalWrite("Testing hex writing with 0xDEADBEEF: ") 84 | terminalWriteHex(cast[uint](0xDEADBEEF)) 85 | terminalWrite("\n") 86 | 87 | #Test the use of timer's wait function 88 | terminalSetColor(makeVGAAttribute(Red, Black)) 89 | terminalWrite("WARNING: Escape causes debug interrupt!!!!\n") 90 | terminalSetColor(makeVGAAttribute(Green, Black)) 91 | 92 | terminalWrite("\nTesting mallocs...\n") 93 | 94 | var xp: ptr uint32 = cast[ptr uint32](kmalloc(cast[uint32](sizeof(uint32)))) 95 | xp[] = 777 96 | var xpAddr: uint32 = cast[uint32](xp) 97 | 98 | when false: 99 | terminalWrite("Got block at: ") 100 | terminalWriteHex(cast[uint32](xp)) 101 | terminalWrite(". Setting the value to: ") 102 | terminalWriteDecimal(xp[]) 103 | terminalWrite("\n") 104 | when false: 105 | for i in 0..3: 106 | var xp: ptr uint32 = cast[ptr uint32](kmalloc(cast[uint32](sizeof(uint32)))) 107 | xp[] = 777 108 | when false: 109 | terminalWrite("Got block at: ") 110 | terminalWriteHex(cast[uint32](xp)) 111 | terminalWrite(". Setting the value to: ") 112 | terminalWriteDecimal(xp[]) 113 | terminalWrite("\n") 114 | 115 | #var yp: ptr uint32 = cast[ptr uint32](kmalloc(cast[uint32](sizeof(uint32)))) 116 | #yp[] = 777 117 | #kfree(cast[uint32](yp)) 118 | 119 | terminalWrite("Freeing first malloc! We should now get its address for this malloc\n") 120 | kfree(cast[uint32](xp)) 121 | xp = cast[ptr uint32](kmalloc(cast[uint32](sizeof(uint32)))) 122 | xp[] = 777 123 | 124 | 125 | #xp = cast[ptr uint32](kmalloc(cast[uint32](sizeof(uint32)))) 126 | var op = cast[ptr uint32](kmalloc(cast[uint32](sizeof(uint32)))) 127 | var tp = cast[ptr uint32](kmalloc(cast[uint32](sizeof(uint32)))) 128 | var yp = cast[ptr uint32](kmalloc(cast[uint32](sizeof(uint32)))) 129 | var zp = cast[ptr uint32](kmalloc(cast[uint32](sizeof(uint32)))) 130 | 131 | kfree(cast[uint32](xp)) 132 | 133 | terminalWrite("Malloc and Free tests: ") 134 | 135 | if xpAddr == cast[uint32](xp): 136 | terminalWrite("SUCCESS!\n") 137 | else: 138 | terminalWrite("FAILURE!\n") 139 | while true: 140 | discard 141 | 142 | terminalWrite("Testing merges on free...\n") 143 | kfree(cast[uint32](op)) 144 | kfree(cast[uint32](tp)) 145 | kfree(cast[uint32](yp)) 146 | kfree(cast[uint32](zp)) 147 | 148 | 149 | terminalWrite("Testing math...\n") 150 | 151 | terminalWrite("Testing log2(1) should be 0: ") 152 | #terminalWriteDecimal(log2(1)) 153 | if log2(1) == 0: 154 | terminalWrite("SUCCESS!\n") 155 | else: 156 | terminalWrite("FAILURE!\n") 157 | 158 | terminalWrite("Testing 2^0 should be 1: ") 159 | if pow(2, 0) == 1: 160 | terminalWrite("SUCCESS!\n") 161 | else: 162 | terminalWrite("FAILURE!\n") 163 | 164 | terminalWrite("Testing 0^1 should be 0: ") 165 | if pow(0, 1) == 0: 166 | terminalWrite("SUCCESS!\n") 167 | else: 168 | terminalWrite("FAILURE!\n") 169 | 170 | terminalSlowWrite("Well actually...\n", 4) 171 | #terminalWrite("Testing 0^0 should fault: ") 172 | #terminalWriteDecimal(pow(0, 0)) 173 | #terminalWrite("\n") 174 | 175 | while true: 176 | discard 177 | -------------------------------------------------------------------------------- /source/kernel.nim.cfg: -------------------------------------------------------------------------------- 1 | --cpu:i386 2 | --boundChecks:off 3 | --passc:"-w -ffreestanding -O2 -Wall -Wextra" 4 | 5 | --noLinking 6 | 7 | --embedsrc 8 | --os:standalone 9 | --gc:none 10 | 11 | --deadCodeElim:on 12 | --noMain 13 | --parallelBuild:"1" 14 | -------------------------------------------------------------------------------- /source/keyboard.nim: -------------------------------------------------------------------------------- 1 | import merosystem 2 | import tty 3 | 4 | proc scanCodeToAscii(scancode: uint8):char = 5 | case scancode 6 | of 0x00: 7 | return chr(0) 8 | of 14: 9 | return chr(8) 10 | of 16: 11 | return 'q' 12 | of 17: 13 | return 'w' 14 | of 18: 15 | return 'e' 16 | of 19: 17 | return 'r' 18 | of 20: 19 | return 't' 20 | of 21: 21 | return 'y' 22 | of 22: 23 | return 'u' 24 | of 23: 25 | return 'i' 26 | of 24: 27 | return 'o' 28 | of 25: 29 | return 'p' 30 | of 57: 31 | return ' ' 32 | else: 33 | return chr(0) 34 | 35 | proc keyboardHandler*(regs: ptr registers) {.exportc.}= 36 | #A neat little keyboard thing 37 | #terminalWrite("Got a keyboard interrupt\n") 38 | var scancode: uint8 = inb(0x60) 39 | 40 | if (scancode and 0x80) != 0: 41 | discard 42 | #Got a keyrelease 43 | #terminalWrite("Got scancode release: ") 44 | #terminalWriteDecimal(scancode xor 0x80) 45 | #terminalWrite("\n") 46 | #terminalWrite("Scancode equates to: ") 47 | #let character: char = scanCodeToAscii(scancode xor 0x80) 48 | #if ord(character) != 0: 49 | # terminalPutChar(character) 50 | #else: 51 | # terminalWrite("Unrecognized scancode...") 52 | #terminalWrite("\n") 53 | else: 54 | #terminalWrite("Got scancode push: ") 55 | #terminalWriteDecimal(scancode) 56 | #terminalWrite("\n") 57 | #terminalWrite("Scancode equates to: ") 58 | let character: char = scanCodeToAscii(scancode) 59 | if ord(character) != 0: 60 | terminalPutChar(character) 61 | else: 62 | terminalWrite("GOT DEBUG SIGNAL!!!\n") 63 | terminalWriteDecimal(1 div 0) 64 | terminalWrite("Unrecognized scancode...") 65 | #terminalWrite("\n") 66 | 67 | proc keyboardInstall*() = 68 | #Install they keyboard handler on irq1 69 | {.emit: """ 70 | installHandler(((unsigned int) 1), `keyboardHandler`); 71 | """} 72 | 73 | discard """ 74 | Why not just do this? It seems simpler, after all. 75 | 76 | installHandler(1, keyboardHandler) 77 | 78 | Well, enter one of my 'favorite' parts of working on this: compiler bugs 79 | https://github.com/nim-lang/Nim/issues/3708 80 | """ 81 | 82 | terminalWrite("Keyboard handler installed...\n") 83 | -------------------------------------------------------------------------------- /source/math.nim: -------------------------------------------------------------------------------- 1 | proc log2*(x: int): int = 2 | asm """ 3 | bsr %1, %0 4 | : "=r"(`result`) 5 | : "r"(`x`) 6 | """ 7 | 8 | proc pow*(base: int, power: int): int = 9 | if power == 0: 10 | if base == 0: 11 | asm """ 12 | int $19 13 | """ 14 | result = 1 15 | else: 16 | result = base 17 | for i in 2..power: 18 | result = base * result 19 | -------------------------------------------------------------------------------- /source/memory.nim: -------------------------------------------------------------------------------- 1 | import tty, merosystem, math 2 | type 3 | TreeNode = object 4 | #For use in the free lists 5 | next: ptr TreeNode 6 | 7 | #Hold our children 8 | left: ptr TreeNode 9 | right: ptr TreeNode 10 | 11 | #The address this node is holding 12 | value: uint32 13 | 14 | #Is this specific instance being used? 15 | used: bool 16 | 17 | #The minimum block size is going to be 4K for now, make sure to set max Order 18 | const order0size = 0x1000 19 | const maxOrder = 5 20 | 21 | var freeLists {.noinit.}: ptr array[maxOrder + 1, ptr TreeNode] 22 | var treeRoot: ptr TreeNode 23 | 24 | var endkernel {.importc: "end"}: uint32 25 | var startkernel {.importc: "kernel_start"}: uint32 26 | var buddyHeap: uint32 27 | var endmemorymanagement*: uint32 28 | 29 | #TODO: Implement a method to track sizes with address, array using address as 30 | #index with size in it? 31 | 32 | proc markAddress(address: uint32, mark: bool, order: int) 33 | 34 | 35 | proc getNode(address: uint32, root: ptr TreeNode, currOrder: int, lookingOrder: int): ptr TreeNode = 36 | if currOrder == lookingOrder: 37 | if root.value == address: 38 | result = root 39 | else: 40 | terminalWrite("We can't get this node of order ") 41 | terminalWriteDecimal(lookingOrder) 42 | terminalWrite(" at address ") 43 | terminalWriteHex(address) 44 | terminalWrite("\n") 45 | result = nil 46 | else: 47 | if root.value == address: 48 | result = getNode(address, root.left, currOrder - 1, lookingOrder) 49 | 50 | elif root.right.value <= address: 51 | result = getNode(address, root.right, currOrder - 1, lookingOrder) 52 | 53 | else: 54 | result = getNode(address, root.left, currOrder - 1, lookingOrder) 55 | 56 | proc getNode(address: uint32, order: int): ptr TreeNode = 57 | result = getNode(address, treeRoot, maxOrder, order) 58 | 59 | proc merge(node: ptr TreeNode, order: int): bool = 60 | result = false 61 | var iter = freeLists[order] 62 | 63 | if iter == nil: 64 | return false 65 | 66 | #This is wrong.. but it works? 67 | #var xorVal = ((node.value - 0x2000) xor cast[uint32](order0size * pow(2, order)))#(cast[uint32](order0size * pow(2, order)))) 68 | var buddyVal: uint32 = 69 | if ((node.value - endmemorymanagement) div order0size * cast[uint32](pow(2, order))) mod 2 == 0: 70 | node.value + cast[uint32](order0size * pow(2, order)) 71 | else: 72 | node.value - cast[uint32](order0size * pow(2, order)) 73 | 74 | discard """ 75 | terminalWrite("Buddy value is: ") 76 | terminalWriteHex(buddyVal) 77 | terminalWrite("\n") 78 | """ 79 | 80 | if buddyVal == iter.value: 81 | var mergedNode: ptr TreeNode 82 | if iter.value < node.value: 83 | mergedNode = getNode(iter.value, order + 1) 84 | else: 85 | mergedNode = getNode(node.value, order + 1) 86 | if mergedNode == nil: 87 | return false 88 | 89 | mergedNode.next = freeLists[order + 1] 90 | freeLists[order + 1] = mergedNode 91 | freeLists[order] = freeLists[order].next 92 | iter.next = nil 93 | node.next = nil 94 | result = true 95 | 96 | discard """ 97 | terminalWrite("Merged blocks ") 98 | terminalWriteHex(node.value) 99 | terminalWrite(" and ") 100 | terminalWriteHex(buddyVal) 101 | terminalWrite("\n") 102 | """ 103 | 104 | while iter.next != nil and not result: 105 | var itNext = iter.next 106 | if buddyVal == itNext.value: 107 | var mergedNode: ptr TreeNode 108 | if itNext.value < node.value: 109 | mergedNode = getNode(itNext.value, order + 1) 110 | else: 111 | mergedNode = getNode(node.value, order + 1) 112 | if mergedNode == nil: 113 | terminalWrite("merged node is nil, failing safely\n") 114 | return false 115 | 116 | #Put the new merged free node in the right list 117 | mergedNode.next = freeLists[order + 1] 118 | freeLists[order + 1] = mergedNode 119 | iter.next = iter.next.next 120 | itNext.next = nil 121 | result = true 122 | discard """ 123 | terminalWrite("Merged blocks ") 124 | terminalWriteHex(node.value) 125 | terminalWrite(" and ") 126 | terminalWriteHex(buddyVal) 127 | terminalWrite("\n") 128 | """ 129 | iter = iter.next 130 | #terminalWrite("No merge!\n") 131 | 132 | proc markAddress(address: uint32, root: ptr TreeNode, mark: bool, 133 | currOrder: int, lookingOrder: int) = 134 | #Mark an address as either used or unused 135 | 136 | if currOrder == lookingOrder: 137 | if root.value == address: 138 | #We found it! Mark it! 139 | root.used = mark 140 | return 141 | else: 142 | #We are tryifng to mark something that couldn't have been malloced 143 | terminalWrite("Wrong address at order ") 144 | terminalWriteDecimal(lookingOrder) 145 | terminalWrite(". Got ") 146 | terminalWriteHex(root.value) 147 | terminalWrite(" but expected ") 148 | terminalWriteHex(address) 149 | terminalWrite("\n") 150 | return 151 | 152 | #Navigate down the tree 153 | 154 | if root.value == address: 155 | markAddress(address, root.left, mark, currOrder - 1, lookingOrder) 156 | 157 | elif root.right.value <= address: 158 | markAddress(address, root.right, mark, currOrder - 1, lookingOrder) 159 | 160 | else: 161 | markAddress(address, root.left, mark, currOrder - 1, lookingOrder) 162 | 163 | proc markAddress(address: uint32, mark: bool, order: int) = 164 | #Recursive helper function 165 | markAddress(address, treeRoot, mark, maxOrder, order) 166 | 167 | proc buildTreeFromRoot(root: ptr TreeNode, rootOrder: int) = 168 | #Build a tree for us to play with 169 | if rootOrder != 0: 170 | #if false: 171 | #if root.value == 0x00111000: 172 | root.left = cast[ptr TreeNode](buddyHeap) 173 | root.left.value = root.value 174 | root.left.used = false 175 | root.left.next = nil 176 | 177 | buddyHeap = buddyHeap + cast[uint32](sizeof(TreeNode)) 178 | 179 | root.right = cast[ptr TreeNode](buddyHeap) 180 | root.right.value = root.value + cast[uint32](order0size * pow(2, rootOrder - 1)) 181 | 182 | root.right.used = false 183 | root.right.next = nil 184 | 185 | buddyHeap = buddyHeap + cast[uint32](sizeof(TreeNode)) 186 | 187 | if rootOrder == 1 and false: 188 | terminalWriteHex(root.value) 189 | terminalWrite(" left: ") 190 | terminalWriteHex(root.left.value) 191 | terminalWrite(" right: ") 192 | terminalWriteHex(root.right.value) 193 | terminalWrite("\n") 194 | 195 | buildTreeFromRoot(root.left, rootOrder - 1) 196 | buildTreeFromRoot(root.right, rootOrder - 1) 197 | 198 | proc makeOrderFromOrder(finalOrder: int, beginningOrder: int): uint32 = 199 | #Recursively manipulate blocks until you have made the block you need 200 | 201 | #We are done splitting blocks, return 202 | if beginningOrder == finalOrder: 203 | result = freeLists[finalOrder].value 204 | 205 | var x = freeLists[finalOrder] 206 | freeLists[finalOrder] = freeLists[finalOrder].next 207 | x.next = nil 208 | else: 209 | var x, y: ptr TreeNode 210 | var initial = freeLists[beginningOrder] 211 | x = initial.left 212 | y = initial.right 213 | 214 | freeLists[beginningOrder] = freeLists[beginningOrder].next 215 | initial.next = nil 216 | 217 | x.next = y 218 | y.next = freeLists[beginningOrder - 1] 219 | freeLists[beginningOrder - 1] = x 220 | 221 | #Recursively call until we are at the desired size. 222 | result = makeOrderFromOrder(finalOrder, beginningOrder - 1) 223 | 224 | proc getFreeBlock(size: uint32): uint32 = 225 | #Return an address to a free block 226 | 227 | #Get the order based upon our order0size 228 | let order = if size <= order0size: 0 else: log2(cast[int](size)) - log2(order0size) 229 | 230 | #Iterate until we have a free block to work with 231 | for i in order .. maxOrder: 232 | #If there is a free block of order i... 233 | if freeLists[i] != nil: 234 | result = makeOrderFromOrder(order, i) 235 | markAddress(result, true, order) 236 | #Don't forget to break the loop! 237 | break 238 | 239 | proc allocInstall*() = 240 | buddyHeap = cast[uint32](addr(endkernel)) 241 | 242 | #Init freelists object 243 | freeLists = cast[ptr array[maxOrder + 1, ptr TreeNode]](buddyHeap) 244 | buddyHeap = buddyHeap + cast[uint32](sizeof(array[maxOrder + 1, ptr TreeNode])) 245 | 246 | #Safety precaution, 0 the array 247 | for i in 0 .. maxOrder: 248 | freeLists[i] = nil 249 | 250 | #Give the buddys some space! 251 | endmemorymanagement = buddyHeap + 0x500 252 | 253 | #Align memory to page 254 | endmemorymanagement = endmemorymanagement + 4096 255 | while endmemorymanagement mod 4096 != 0: 256 | endmemorymanagement = endmemorymanagement + 1 257 | 258 | #Tree to keep track of frees 259 | treeRoot = cast[ptr TreeNode](buddyHeap) 260 | treeRoot.used = false 261 | treeRoot.value = endmemorymanagement 262 | buddyHeap = buddyHeap + cast[uint32](sizeof(TreeNode)) 263 | 264 | #Construct the tree 265 | buildTreeFromRoot(treeRoot, maxOrder) 266 | freeLists[maxOrder] = treeRoot 267 | freeLists[maxOrder].next = nil 268 | 269 | 270 | if freeLists[maxOrder] == nil: 271 | terminalWrite("Well, max order is nil in alloc install, this is bad.\n") 272 | 273 | proc kfree(address: uint32, root: ptr TreeNode, order: int) = 274 | #Free the memory in the tree to put back in lists 275 | if root.used and root.value == address: 276 | #We found it, give it back to the lists! 277 | #if order != 0: 278 | # terminalWrite("Not freeing order 0 block?\n") 279 | root.used = false 280 | 281 | #Well, this is a headache 282 | #TODO: Fix whatever is wrong with this awful merge code. 283 | if not merge(root, order): 284 | root.next = freeLists[order] 285 | freeLists[order] = root 286 | return 287 | else: 288 | #We can't go down the tree any further and this isn't the node we need 289 | if order == 0: 290 | terminalWrite("We can't free this!\n") 291 | return 292 | 293 | #Navigate the tree... 294 | if root.value == address: 295 | kfree(address, root.left, order - 1) 296 | 297 | elif root.right.value <= address: 298 | kfree(address, root.right, order - 1) 299 | 300 | else: 301 | kfree(address, root.left, order - 1) 302 | 303 | proc kfree*(address: uint32) = 304 | #Helper function to call recursive 305 | kfree(address, treeRoot, maxOrder) 306 | discard 307 | 308 | proc kmalloc*(size: uint32, align: uint32 = 4): uint32 = 309 | #TODO: THIS MUST BE ALIGNED!!! 310 | let order = if size <= order0size: 0 else: log2(cast[int](size)) - log2(order0size) 311 | if order <= maxOrder: 312 | result = getFreeBlock(size) 313 | else: 314 | terminalWrite("Cannot alloc block that large...") 315 | 316 | proc memcpy*(destination: pointer, source: pointer, size: uint32) {.exportc.} = 317 | var dstu8 = cast[ptr uint8](destination) 318 | var srcu8 = cast[ptr uint8](source) 319 | 320 | for i in 0 .. . So, while reversing the string using arrays would 136 | have worked, using a similar method of swapping the terminal buffer entries 137 | will work just as well 138 | """ 139 | 140 | let cursorStart = terminalColumn 141 | var endNumIndex = -1 142 | 143 | var numCopy = num 144 | while numCopy != 0: 145 | #Add the number to the ascii code for 0 146 | terminalPutChar(chr(cast[uint](48) + (numCopy mod 10))) 147 | #Lose the rightmost digit 148 | numCopy = numCopy div 10 149 | 150 | inc(endNumIndex) 151 | 152 | for i in 0..endNumIndex div 2: 153 | #Swap in memory 154 | let first = terminalBuffer[terminalRow*VGAWidth + cursorStart + i] 155 | let last = terminalBuffer[terminalRow*VGAWidth + cursorStart + endNumIndex - i] 156 | 157 | terminalBuffer[terminalRow*VGAWidth + cursorStart + i] = last 158 | terminalBuffer[terminalRow*VGAWidth + cursorStart + endNumIndex - i] = first 159 | 160 | proc terminalWriteDecimal*(num: int) = 161 | #Properly add a negative for less than zero 162 | if num < 0: 163 | terminalPutChar('-') 164 | if num == 0: 165 | terminalPutChar('0') 166 | return 167 | 168 | discard """ 169 | Nim likes to replace array[0..n, char] with a cstring.. this won't do as we 170 | cannot include . So, while reversing the string using arrays would 171 | have worked, using a similar method of swapping the terminal buffer entries 172 | will work just as well 173 | """ 174 | 175 | let cursorStart = terminalColumn 176 | var endNumIndex = -1 177 | 178 | var numCopy = num 179 | while numCopy != 0: 180 | #Add the number to the ascii code for 0 181 | terminalPutChar(chr(48 + (numCopy mod 10))) 182 | #Lose the rightmost digit 183 | numCopy = numCopy div 10 184 | 185 | inc(endNumIndex) 186 | 187 | for i in 0..endNumIndex div 2: 188 | #Swap in memory 189 | let first = terminalBuffer[terminalRow*VGAWidth + cursorStart + i] 190 | let last = terminalBuffer[terminalRow*VGAWidth + cursorStart + endNumIndex - i] 191 | 192 | terminalBuffer[terminalRow*VGAWidth + cursorStart + i] = last 193 | terminalBuffer[terminalRow*VGAWidth + cursorStart + endNumIndex - i] = first 194 | 195 | proc terminalWriteHex*(num: uint) = 196 | terminalWrite("0x") 197 | 198 | if num == 0: 199 | terminalWrite("0") 200 | return 201 | 202 | discard """ 203 | Nim likes to replace array[0..n, char] with a cstring.. this won't do as we 204 | cannot include . So, while reversing the string using arrays would 205 | have worked, using a similar method of swapping the terminal buffer entries 206 | will work just as well 207 | """ 208 | 209 | let cursorStart = terminalColumn 210 | var endNumIndex = -1 211 | 212 | var numCopy = num 213 | while numCopy != 0: 214 | let place = numCopy mod 16 215 | numCopy = numCopy div 16 216 | if place > cast[uint](9): 217 | terminalPutChar(chr((cast[uint](65) + place - 10))) 218 | else: 219 | terminalPutChar(chr(cast[uint](48) + place)) 220 | 221 | inc(endNumIndex) 222 | 223 | for i in 0..endNumIndex div 2: 224 | #Swap in memory 225 | let first = terminalBuffer[terminalRow*VGAWidth + cursorStart + i] 226 | let last = terminalBuffer[terminalRow*VGAWidth + cursorStart + endNumIndex - i] 227 | 228 | terminalBuffer[terminalRow*VGAWidth + cursorStart + i ] = last 229 | terminalBuffer[terminalRow*VGAWidth + cursorStart + endNumIndex - i] = first 230 | -------------------------------------------------------------------------------- /source/vga.nim: -------------------------------------------------------------------------------- 1 | type 2 | #VGA data helpers 3 | VidMem* = ptr array[0..65_000, VGAEntry] 4 | VGAColor* = enum 5 | Black = 0, 6 | Blue = 1, 7 | Green = 2, 8 | Cyan = 3, 9 | Red = 4, 10 | Magenta = 5, 11 | Brown = 6, 12 | LightGrey = 7, 13 | DarkGrey = 8, 14 | LightBlue = 9, 15 | LightGreen = 10, 16 | LightCyan = 11, 17 | LightRed = 12, 18 | LightMagenta = 13, 19 | LightBrown = 14, 20 | White = 15 21 | VGAEntry* = distinct uint16 22 | VGAAttribute* = distinct uint8 23 | 24 | const 25 | #Initial vga environment 26 | VGAWidth* = 80 27 | VGAHeight* = 25 28 | VGAMem* = cast[VidMem](0xB8000) 29 | 30 | proc makeVGAAttribute*(foreground: VGAColor, background: VGAColor): VGAAttribute = 31 | #Make a specific forground and background attribute 32 | return (ord(foreground).uint8 or (ord(background).uint8 shl 4)).VGAAttribute 33 | 34 | proc makeVGAEntry*(c: char, attribute: VGAAttribute): VGAEntry = 35 | #Apply an attribute to a character to make an entry 36 | var c16: uint16 = ord(c).uint16 37 | var color16: uint16 = ord(attribute).uint16 38 | return (c16 or (color16 shl 8)).VGAEntry 39 | --------------------------------------------------------------------------------