我有兴趣了解如何在没有unix系统调用等高级函数的帮助下编译/创建一个非常简单的语言(即brainfuck)。我想在一些依赖于CPU的低级程序集中为该语言编写一个编译器,这样我就可以用简单的语言提供源代码并最终得到二进制文件。不确定这是否清楚,但基本问题是如何在没有硬件中已有的任何东西的帮助下将源转换为二进制文件。
编辑:更简洁的问题陈述......
下式给出:
- 硬件(主板/ CPU等)
NOT GIVEN:
-unix / DOS
-C / FORTRAN /任何其他语言
我如何实施像brainfuck这样的简单语言?
我知道有更多实用的编译方法,但我对此有兴趣用于教育目的。
很抱歉,如果这个问题多余或明显 - 我不是计算机科学家,所以也许我只是不知道在线找到问题解决方案的正确词汇。如果任何人可以提供关于该主题的链接或文本,将不胜感激。
答案 0 :(得分:1)
查看维基百科上的描述这不是一项艰巨的任务。我可能仍然会用你知道的某种语言开始,也许不喜欢。 C是个不错的选择。文件I / O是一个小型或大型项目,具体取决于平台等。稍后担心,编译语言的“源”。对于该源中的每个字符,执行任务
> ++ptr;
< --ptr;
+ ++*ptr;
etc
然后将其转换为汇编。你只需要一个寄存器来保存ptr,几行asm来初始化数组/ ram并将寄存器/ ptr设置为开头。另一个注册来完成源代码。你只需要找8个字符,你可以if-then-else你的方式通过那些,除非有一些模式的东西,使他们更容易处理。如果你想要你可以创建一个256byte的查找表,并将其用于该指令的处理程序的地址或将它们转换为0-7的整数,并在跳转表中使用它,无论如何。
那是一个解析器,不一定是编译器。我会用C或某种高级语言编写编译器,它接受一个字节数组,即程序,对于每个输出实现该指令的asm源代码的指令,输入输出时得到一个小于字节(使用ARM asm)
add r0,#1
减号
ldr r1,[r0]
sub r1,#1
str r1,[r0]
r0是ptr寄存器而r1只是帮忙。
如果你真的反对使用像printf这样的调用,那么让这段代码的输出为字节数组,这是asm的ascii,输出每个字符a,d,d,space,r,0,逗号,#,1,cr,lf等。在asm以及一些高级语言中实现相当容易。如果你想直接使用二进制文件,那么只需输出机器代码即可。
将源字符串放入此编译器并将输出转换为某个文件然后可以执行该系统调用。如果您在同一平台上运行,则可以避免输出为文件,并且可以在某个地址构建机器代码的意义上进行自修改代码,然后在完成解析后跳转到该地址执行。
编写这个答案比用C或asm实现解决方案花了很多倍。你遇到的确切困难是什么?答案 1 :(得分:1)
你可以很容易地将brainfuck源代码编译成DOS .COM应用程序(你还需要NASM或一些额外的代码来发出指令操作码并计算跳转)。下面是一个稍微修改过的bf解释器,变成了各种编译器:
// file: bfcompil.c
#include <stddef.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#define MAX_CODE_SIZE 30000
char code[MAX_CODE_SIZE];
char* pc = &code[0];
char* pcEnd = &code[0];
#define MAX_DATA_SIZE 30000
char data[MAX_DATA_SIZE] = { 0 };
char* pd = &data[0];
// Structures for quick bracket matching
unsigned brStack[MAX_CODE_SIZE];
unsigned brSptr = 0;
unsigned brMatch[MAX_CODE_SIZE];
int main(int argc, char** argv)
{
FILE* f = NULL;
int ch;
if (argc != 2)
{
fprintf(stderr, "usage:\n bfcompil <brainfuck-source-code-file>\n"
"bfcompil will output NASM-compilable source code for"
"a DOS program\n");
return EXIT_FAILURE;
}
if ((f = fopen(argv[1], "rb")) == NULL)
{
fprintf(stderr, "can't open file \"%s\" for reading\n", argv[1]);
return EXIT_FAILURE;
}
while ((ch = getc(f)) != EOF)
{
if (strchr(" \t\r\n", ch) != NULL) // skip white space
{
continue;
}
else if (strchr("><+-.,[]", ch) != NULL) // store valid commands
{
if (pcEnd >= &code[sizeof(code)])
{
fprintf(stderr, "too many commands in file \"%s\", expected at most "
"%u commands\n", argv[1], (unsigned)sizeof(code));
fclose(f);
return EXIT_FAILURE;
}
if (ch == '[')
{
brStack[brSptr++] = (unsigned)(pcEnd - &code[0]);
}
else if (ch == ']')
{
if (brSptr == 0)
{
fprintf(stderr, "unmatched ']' in file \"%s\"\n", argv[1]);
fclose(f);
return EXIT_FAILURE;
}
brSptr--;
brMatch[brStack[brSptr]] = (unsigned)(pcEnd - &code[0]);
brMatch[pcEnd - &code[0]] = brStack[brSptr];
}
*pcEnd++ = ch;
}
else // fail on invalid commands
{
fprintf(stderr, "unexpected character '%c' in file \"%s\", valid command "
"set is: \"><+-.,[]\"\n", ch, argv[1]);
fclose(f);
return EXIT_FAILURE;
}
}
fclose(f);
if (brSptr != 0)
{
fprintf(stderr, "unmatched '[' in file \"%s\"\n", argv[1]);
return EXIT_FAILURE;
}
if (pcEnd == &code[0])
{
fprintf(stderr, "no commands found in file \"%s\"\n", argv[1]);
return EXIT_FAILURE;
}
printf("; how to compile: nasm -f bin <input file with this code.asm> -o "
"<output executable.com>\n\n"
"org 0x100\n"
"bits 16\n\n"
" mov bx, data\n"
" mov di, bx\n"
" mov cx, 30000\n"
" xor al, al\n"
" cld\n"
" rep stosb\n\n"
" jmp code\n\n"
"print:\n"
" mov ah, 2\n"
" cmp byte [bx], 10\n"
" jne lprint1\n"
" mov dl, 13\n"
" int 0x21\n"
"lprint1:\n"
" mov dl, [bx]\n"
" int 0x21\n"
" ret\n\n"
#if 01
// buffered input
"input:\n"
" cmp byte [kbdbuf+1], 0\n"
" jne linput1\n"
" mov ah, 0xa\n"
" mov dx, kbdbuf\n"
" int 0x21\n"
" inc byte [kbdbuf+1]\n"
"linput1:\n"
" mov al, [kbdbuf+2]\n"
" cmp al, 13\n"
" jne linput4\n"
" mov al, 10\n"
"linput4:\n"
" mov [bx], al\n"
" mov si, kbdbuf+3\n"
" mov di, kbdbuf+2\n"
" xor cx, cx\n"
" dec byte [kbdbuf+1]\n"
" mov cl, [kbdbuf+1]\n"
" jz linput3\n"
"linput2:\n"
" lodsb\n"
" stosb\n"
" loop linput2\n"
"linput3:\n"
" ret\n\n"
#else
// unbuffered input
"input:\n"
" mov ah, 1\n"
" int 0x21\n"
" cmp al, 13\n"
" jne linput\n"
" mov al, 10\n"
"linput:\n"
" mov [bx], al\n"
" ret\n\n"
#endif
"code:\n\n");
for (pc = &code[0]; pc < pcEnd; pc++)
{
switch (*pc)
{
case '>':
printf(" inc bx\n");
break;
case '<':
printf(" dec bx\n");
break;
case '+':
printf(" inc byte [bx]\n");
break;
case '-':
printf(" dec byte [bx]\n");
break;
case '.':
printf(" call print\n");
break;
case ',':
printf(" call input\n");
break;
case '[':
printf("label%u:\n", (unsigned)(pc - &code[0]));
printf(" cmp byte [bx], 0\n");
printf(" je label%u\n", (unsigned)brMatch[pc - &code[0]]);
break;
case ']':
printf(" jmp label%u\n", brMatch[pc - &code[0]]);
printf("label%u:\n", (unsigned)(pc - &code[0]));
break;
}
}
printf("\n ret\n\n");
printf("kbdbuf:\n"
" db 254\n"
" db 0\n"
" times 256 db 0\n\n");
printf("data:\n");
return EXIT_SUCCESS;
}
如果你喂它hello world程序:
++++++++++[>+++++++>++++++++++>+++>+<<<<-]>++.>+.+++++++..+++.>++.<<+++++++++++++++.>.+++.------.--------.>+.>.
它将生成可编译的汇编代码:
; how to compile: nasm -f bin <input file with this code.asm> -o <output executable.com>
org 0x100
bits 16
mov bx, data
mov di, bx
mov cx, 30000
xor al, al
cld
rep stosb
jmp code
print:
mov ah, 2
cmp byte [bx], 10
jne lprint1
mov dl, 13
int 0x21
lprint1:
mov dl, [bx]
int 0x21
ret
input:
cmp byte [kbdbuf+1], 0
jne linput1
mov ah, 0xa
mov dx, kbdbuf
int 0x21
inc byte [kbdbuf+1]
linput1:
mov al, [kbdbuf+2]
cmp al, 13
jne linput4
mov al, 10
linput4:
mov [bx], al
mov si, kbdbuf+3
mov di, kbdbuf+2
xor cx, cx
dec byte [kbdbuf+1]
mov cl, [kbdbuf+1]
jz linput3
linput2:
lodsb
stosb
loop linput2
linput3:
ret
code:
inc byte [bx]
inc byte [bx]
inc byte [bx]
inc byte [bx]
inc byte [bx]
inc byte [bx]
inc byte [bx]
inc byte [bx]
inc byte [bx]
inc byte [bx]
label10:
cmp byte [bx], 0
je label41
inc bx
inc byte [bx]
inc byte [bx]
inc byte [bx]
inc byte [bx]
inc byte [bx]
inc byte [bx]
inc byte [bx]
inc bx
inc byte [bx]
inc byte [bx]
inc byte [bx]
inc byte [bx]
inc byte [bx]
inc byte [bx]
inc byte [bx]
inc byte [bx]
inc byte [bx]
inc byte [bx]
inc bx
inc byte [bx]
inc byte [bx]
inc byte [bx]
inc bx
inc byte [bx]
dec bx
dec bx
dec bx
dec bx
dec byte [bx]
jmp label10
label41:
inc bx
inc byte [bx]
inc byte [bx]
call print
inc bx
inc byte [bx]
call print
inc byte [bx]
inc byte [bx]
inc byte [bx]
inc byte [bx]
inc byte [bx]
inc byte [bx]
inc byte [bx]
call print
call print
inc byte [bx]
inc byte [bx]
inc byte [bx]
call print
inc bx
inc byte [bx]
inc byte [bx]
call print
dec bx
dec bx
inc byte [bx]
inc byte [bx]
inc byte [bx]
inc byte [bx]
inc byte [bx]
inc byte [bx]
inc byte [bx]
inc byte [bx]
inc byte [bx]
inc byte [bx]
inc byte [bx]
inc byte [bx]
inc byte [bx]
inc byte [bx]
inc byte [bx]
call print
inc bx
call print
inc byte [bx]
inc byte [bx]
inc byte [bx]
call print
dec byte [bx]
dec byte [bx]
dec byte [bx]
dec byte [bx]
dec byte [bx]
dec byte [bx]
call print
dec byte [bx]
dec byte [bx]
dec byte [bx]
dec byte [bx]
dec byte [bx]
dec byte [bx]
dec byte [bx]
dec byte [bx]
call print
inc bx
inc byte [bx]
call print
inc bx
call print
ret
kbdbuf:
db 254
db 0
times 256 db 0
data:
如果你编译它,你将能够在DOS,Windows 9x / XP(可能是32位Vista / 7)和DosBox中运行它。
毫不奇怪,输出是:
Hello World!
UPDATE :上述代码中基于DOS的输入和输出例程可以通过直接访问屏幕缓冲区和键盘端口来替换。键盘代码还需要处理键盘中断。在x86 PC上做起来并不是很难。你真的可以实现一种语言的编译器,可以在没有操作系统的裸硬件上运行。
您还应该查看Forth
,因为这正是给定环境的语言类型。它很容易实现。比C语言要容易得多,比大脑更容易,有点与装配相当。
更新2 :这是一个小型(大小约1KB)的brainfuck解释器,它没有使用任何DOS或BIOS功能:
; file: bfint.asm
; compile: nasm.exe -f bin bfint.asm -o bfint.com
; run in: DOS, DosBox or equivalent
bits 16
org 0x100
section .text
SCREEN_WIDTH equ 80
SCREEN_HEIGHT equ 25
SCAN_BUF_SIZE equ 256
MAX_CODE_SIZE equ 20000
MAX_DATA_SIZE equ 30000
cld
; set new keyboard (IRQ1) ISR
push byte 0
pop es
cli ; update ISR address w/ ints disabled
mov word [es:9*4], Irq1Isr
mov [es:9*4+2], cs
sti
push cs
pop es
Restart:
call ClearScreen
mov si, MsgHello
call PrintStr
mov word [CodeSize], 0
mov byte [EnterCount], 0
WaitForKey:
call GetKey
; Escape erases code
cmp ah, 1 ; Escape
je Restart
; Non-characters are ignored
cmp al, 0 ; non-character key
je WaitForKey
; Enter is "printed" but not stored, use for formatting
cmp al, 10 ; Enter
je KeyEnter
mov byte [EnterCount], 0
; Backspace deletes last character
cmp al, 8 ; Backspace
je KeyBackspace
; Space is printed but not stored, use for formatting
cmp al, " " ; Space
je PrintOnly
; 0 runs a test program
cmp al, "0"
je TestProgram
; Other chracters are stored as code
mov bx, [CodeSize]
cmp bx, MAX_CODE_SIZE
jae ErrCodeTooBig
mov [Code + bx], al
inc word [CodeSize]
PrintOnly:
call PrintChar
jmp WaitForKey
ErrCodeTooBig:
mov si, MsgCodeTooBig
call PrintStr
mov word [CodeSize], 0
jmp WaitForKey
KeyEnter:
call PrintChar
inc byte [EnterCount]
cmp byte [EnterCount], 1
je WaitForKey
mov byte [EnterCount], 0
call Execute
jmp WaitForKey
KeyBackspace:
call PrintChar
cmp word [CodeSize], 0
je WaitForKey
dec word [CodeSize]
jmp WaitForKey
TestProgram:
mov si, TestCode
mov di, Code
mov cx, TestCodeEnd - TestCode
mov [CodeSize], cx
rep movsb
call Execute
jmp WaitForKey
Execute:
mov si, Code ; code start
xor bp, bp ; instruction index
mov di, Data ; data start
mov cx, MAX_DATA_SIZE
xor al, al
rep stosb
sub di, MAX_DATA_SIZE
xor bx, bx ; data index
ExecuteLoop:
cmp bp, [CodeSize]
jae ExecuteDone
mov al, [bp+si]
cmp al, ">"
je IncPtr
cmp al, "<"
je DecPtr
cmp al, "+"
je IncData
cmp al, "-"
je DecData
cmp al, "."
je PrintData
cmp al, ","
je InputData
cmp al, "["
je While
cmp al, "]"
je EndWhile
mov si, MsgInvalidChar
call PrintStr
call PrintChar
mov al, 10
call PrintChar
jmp ExecuteDone
IncPtr:
inc bx
jmp ExecuteContinue
DecPtr:
dec bx
jmp ExecuteContinue
IncData:
inc byte [bx+di]
jmp ExecuteContinue
DecData:
dec byte [bx+di]
jmp ExecuteContinue
PrintData:
mov al, [bx+di]
call PrintChar
jmp ExecuteContinue
InputData:
call GetKey
or al, al
jz InputData
mov [bx+di], al
jmp ExecuteContinue
While:
cmp byte [bx+di], 0
jne ExecuteContinue
mov ax, 1
mov dx, "[]"
call FindMatchingBracket
ExecuteContinue:
inc bp
jmp ExecuteLoop
EndWhile:
mov ax, -1
mov dx, "]["
call FindMatchingBracket
jmp ExecuteLoop
ExecuteDone:
mov word [CodeSize], 0
mov si, MsgCompleted
jmp PrintStr
FindMatchingBracket:
xor cx, cx
FindMatchingBracket1:
cmp byte [bp+si], dl
jne FindMatchingBracket2
inc cx
jmp FindMatchingBracket3
FindMatchingBracket2:
cmp byte [bp+si], dh
jne FindMatchingBracket3
dec cx
jnz FindMatchingBracket3
ret
FindMatchingBracket3:
add bp, ax
jmp FindMatchingBracket1
; Inputs:
; AL = ASCII character code
PrintChar:
; assuming it's a color text mode (not monochrome or graphics)
pusha
push es
push word 0xb800
pop es
mov bx, [CursorPos]
cmp al, 8
je PrintCharBackSpace
cmp al, 10
je PrintCharBackLF
cmp al, 13
je PrintCharBackCR
mov [es:bx], al
call AdvanceCursorPosition
jmp PrintCharDone
PrintCharBackSpace:
; move the cursor back and erase the last character
or bx, bx
jz PrintCharDone
dec bx
dec bx
mov word [es:bx], 0x0720
jmp PrintCharSetCursorPos
PrintCharBackLF:
; move the cursor to the beginning of the next line - '\n' behavior
add bx, SCREEN_WIDTH * 2
cmp bx, SCREEN_WIDTH * SCREEN_HEIGHT * 2
jc PrintCharBackCR
sub bx, SCREEN_WIDTH * 2
call ScrollUp
PrintCharBackCR:
; move the cursor to the beginning of the current line - '\r' behavior
mov ax, SCREEN_WIDTH * 2
xchg ax, bx
xor dx, dx
div bx
mul bx
mov bx, ax
PrintCharSetCursorPos:
mov [CursorPos], bx
shr bx, 1
call SetCursorPosition
PrintCharDone:
PopEsAllRet:
pop es
popa
ret
ClearScreen:
; assuming it's a color text mode (not monochrome or graphics)
pusha
push es
push word 0xb800
pop es
xor di, di
mov cx, SCREEN_WIDTH * SCREEN_HEIGHT
mov ax, 0x0720 ; character = space, color = lightgray on black
rep stosw
xor bx, bx
mov [CursorPos], bx
call SetCursorPosition
jmp PopEsAllRet
ScrollUp:
; assuming it's a color text mode (not monochrome or graphics)
pusha
push es
push ds
push word 0xb800
pop es
push es
pop ds
mov si, SCREEN_WIDTH * 2
xor di, di
mov cx, SCREEN_WIDTH * (SCREEN_HEIGHT - 1)
rep movsw
mov cx, SCREEN_WIDTH
mov ax, 0x0720 ; character = space, color = lightgray on black
rep stosw
pop ds
jmp PopEsAllRet
; Inputs:
; DS:SI = address of NUL-terminated ASCII string
PrintStr:
pusha
PrintStr1:
lodsb
or al, al
jz PrintStrDone
call PrintChar
jmp PrintStr1
PrintStrDone:
popa
ret
; Inputs:
; BX = Y * SCREEN_WIDTH + X
SetCursorPosition:
; assuming it's a color text mode (not monochrome or graphics)
pusha
%if 0
mov dx, 0x3d4
mov al, 0x0f
out dx, al
inc dx
mov al, bl
out dx, al
dec dx
mov al, 0x0e
out dx, al
inc dx
mov al, bh
out dx, al
%else
mov dx, 0x3d4
mov al, 0x0f
mov ah, bl
out dx, ax
dec al
mov ah, bh
out dx, ax
%endif
popa
ret
AdvanceCursorPosition:
; assuming it's a color text mode (not monochrome or graphics)
pusha
mov ax, [CursorPos]
inc ax
inc ax
cmp ax, SCREEN_WIDTH * SCREEN_HEIGHT * 2
jc AdvanceCursorPosition1
sub ax, SCREEN_WIDTH * 2
call ScrollUp
AdvanceCursorPosition1:
mov [CursorPos], ax
shr ax, 1
xchg ax, bx
call SetCursorPosition
popa
ret
; Outputs:
; AH = scan code
; AL = character
GetKey:
push bx
push si
GetKeyRepeat:
mov ax, [ScanWriteIdx]
mov si, [ScanReadIdx]
sub ax, si
jz GetKeyRepeat
mov bx, si
mov ax, [ScanBuf + bx + si]
inc si
and si, SCAN_BUF_SIZE - 1
mov [ScanReadIdx], si
pop si
pop bx
ret
Irq1Isr:
pusha
push ds
push cs
pop ds
; read keyboard scan code
in al, 0x60
cmp al, 0x2a ; Left Shift down
jne Irq1Isr1
or byte [Shift], 1
Irq1Isr1:
cmp al, 0x36 ; Right Shift down
jne Irq1Isr2
or byte [Shift], 2
Irq1Isr2:
cmp al, 0xaa ; Left Shift up
jne Irq1Isr3
and byte [Shift], ~1
Irq1Isr3:
cmp al, 0xb6 ; Right Shift up
jne Irq1Isr4
and byte [Shift], ~2
Irq1Isr4:
test al, 0x80
jnz Irq1IsrEois ; key released
mov ah, al
cmp al, 58
jc Irq1Isr5
xor al, al ; don't translate non-character keys
jmp Irq1Isr7
Irq1Isr5:
mov bx, ScanToChar
cmp byte [Shift], 0
je Irq1Isr6
add bx, ScanToCharShift - ScanToChar
Irq1Isr6:
xlatb
Irq1Isr7:
mov bx, [ScanWriteIdx]
mov di, bx
mov [ScanBuf + bx + di], ax
inc bx
and bx, SCAN_BUF_SIZE - 1
mov [ScanWriteIdx], bx
Irq1IsrEois:
%if 0
; send EOI to XT keyboard
in al, 0x61
mov ah, al
or al, 0x80
out 0x61, al
mov al, ah
out 0x61, al
%endif
; send EOI to master PIC
mov al, 0x20
out 0x20, al
pop ds
popa
iret
ScanToChar:
db 0 ; unused
db 0 ; Escape
db "1234567890-="
db 8 ; Backspace
db 9 ; Tab
db "qwertyuiop[]"
db 10 ; Enter
db 0 ; Ctrl
db "asdfghjkl;'`"
db 0 ; Left Shift
db "\zxcvbnm,./"
db 0 ; Right Shift
db 0 ; Print Screen
db 0 ; Alt
db " " ; Space
ScanToCharShift:
db 0 ; unused
db 0 ; Escape
db "!@#$%^&*()_+"
db 8 ; Backspace
db 9 ; Tab
db "QWERTYUIOP{}"
db 10 ; Enter
db 0 ; Ctrl
db 'ASDFGHJKL:"~'
db 0 ; Left Shift
db "|ZXCVBNM<>?"
db 0 ; Right Shift
db 0 ; Print Screen
db 0 ; Alt
db " " ; Space
MsgHello:
db "Brainfuck Interpreter", 10, 10
db "Press 0 to run test code OR", 10
db "Type your code.", 10
db "Use Esc to erase it all or Backspace to delete last character.", 10
db "Press Enter twice to run it.", 10, 10, 0
MsgCodeTooBig:
db 10, "Code's too big", 10, 0
MsgCompleted:
db 10, "Code's completed", 10, 0
MsgInvalidChar:
db 10, "Invalid character: ", 0
Shift db 0
CursorPos dw 0
ScanReadIdx dw 0
ScanWriteIdx dw 0
EnterCount db 0
CodeSize dw 0
TestCode:
; Hello World!
db "++++++++++[>+++++++>++++++++++>+++>+<<<<-]>++.>+.+++++++..+++.>++.<<+++++++++++++++.>.+++.------.--------.>+.>."
; Squares of 0 through 100
; db "++++[>+++++<-]>[<+++++>-]+<+[>[>+>+<<-]++>>[<<+>>-]>>>[-]++>[-]+>>>+[[-]++++++>>>]<<<[[<++++++++<++>>-]+<.<[>----<-]<]<<[>>>>>[>>>[-]+++++++++<[>-<-]+++++++++>[-[<->-]+[<<<]]<[>+<-]>]<<-]<<-]"
; ROT13
; db "+[,+[-[>+>+<<-]>[<+>-]+>>++++++++[<-------->-]<-[<[-]>>>+[<+<+>>-]<[>+<-]<[<++>>>+[<+<->>-]<[>+<-]]>[<]<]>>[-]<<<[[-]<[>>+>+<<<-]>>[<<+>>-]>>++++++++[<-------->-]<->>++++[<++++++++>-]<-<[>>>+<<[>+>[-]<<-]>[<+>-]>[<<<<<+>>>>++++[<++++++++>-]>-]<<-<-]>[<<<<[-]>>>>[<<<<->>>>-]]<<++++[<<++++++++>>-]<<-[>>+>+<<<-]>>[<<+>>-]+>>+++++[<----->-]<-[<[-]>>>+[<+<->>-]<[>+<-]<[<++>>>+[<+<+>>-]<[>+<-]]>[<]<]>>[-]<<<[[-]<<[>>+>+<<<-]>>[<<+>>-]+>------------[<[-]>>>+[<+<->>-]<[>+<-]<[<++>>>+[<+<+>>-]<[>+<-]]>[<]<]>>[-]<<<<<------------->>[[-]+++++[<<+++++>>-]<<+>>]<[>++++[<<++++++++>>-]<-]>]<[-]++++++++[<++++++++>-]<+>]<.[-]+>>+<]>[[-]<]<]"
TestCodeEnd:
section .bss
ScanBuf:
resw SCAN_BUF_SIZE
Code:
resb MAX_CODE_SIZE
Data:
resb MAX_DATA_SIZE
如果您想将DOS(作为托管环境)和NASM从图片中删除,欢迎您手动对上述汇编代码进行编码,从中制作可启动软盘并启动它。
答案 2 :(得分:0)
规范的编译器学习书是龙书,http://dragonbook.stanford.edu/。
然而,它确实更多地指向......精致的语言。你可能不想谈论无上下文的解析等(虽然我做推荐那本书,它是双加硬但真棒。)
考虑到这一点,你可能想要找到一个非常简单的语言的解释器或编译器 - 也许是Brainfuck本身,也许像Scheme实现更有用。阅读,分析,了解它的作用。实现编译器使用的低级库函数,调整其代码生成器以输出您想要定位的任何品牌的机器代码,然后就完成了。
答案 3 :(得分:0)
实际上,我也有类似的项目。你想要的是编写一个在裸硬件上运行的编译器(没有任何操作系统)。 编译器只是一个类似于其他所有程序的程序,除了它将像你的情况一样在裸硬件上运行。
您可以考虑为编译器使用引导加载程序(引导加载程序不是操作系统)。引导加载程序通常会将操作系统从磁盘加载到内存中,以便仅在加载编译器而不是操作系统时执行。
有许多免费和开源的引导加载程序(谷歌为他们)。选择一个适合您需求的,或者如果您像我一样好奇/好奇,您甚至可以自己编写。
选择引导加载程序(或编写引导加载程序)要求您了解目标系统的引导方式 - 通过BIOS(旧)或UEFI(新的。它是BIOS的替代品)。随着编程语言的成熟,您可以用新的编程语言编写自己的引导加载程序。
希望这有帮助