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HW1, HW2, HW2 bonus, HW3

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A.Olokhtonov 2 years ago
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  1. 6
      .gitignore
  2. 1
      1-reg-reg-decode/listing_0037_single_register_mov
  3. 19
      1-reg-reg-decode/listing_0037_single_register_mov.asm
  4. 1
      1-reg-reg-decode/listing_0038_many_register_mov
  5. 29
      1-reg-reg-decode/listing_0038_many_register_mov.asm
  6. 56
      1-reg-reg-decode/main.c
  7. BIN
      2-more-decode/listing_0039_more_movs
  8. 45
      2-more-decode/listing_0039_more_movs.asm
  9. BIN
      2-more-decode/listing_0040_challenge_movs
  10. 38
      2-more-decode/listing_0040_challenge_movs.asm
  11. 281
      2-more-decode/main.c
  12. 12
      2-more-decode/test.sh
  13. BIN
      3-arithmetic/listing_0041_add_sub_cmp_jnz
  14. 121
      3-arithmetic/listing_0041_add_sub_cmp_jnz.asm
  15. 349
      3-arithmetic/main.c
  16. 166
      common.h

6
.gitignore vendored
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test
test.asm
test2
test2.asm
*.hex
8086-decode

1
1-reg-reg-decode/listing_0037_single_register_mov
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菓

19
1-reg-reg-decode/listing_0037_single_register_mov.asm
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; ========================================================================
;
; (C) Copyright 2023 by Molly Rocket, Inc., All Rights Reserved.
;
; This software is provided 'as-is', without any express or implied
; warranty. In no event will the authors be held liable for any damages
; arising from the use of this software.
;
; Please see https://computerenhance.com for further information
;
; ======================================================================== */
; ========================================================================
; LISTING 37
; ========================================================================
bits 16
mov cx, bx

1
1-reg-reg-decode/listing_0038_many_register_mov
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‰Ùˆå‰Ú‰Þ‰ûˆÈˆí‰Ã‰ó‰ü‰Å

29
1-reg-reg-decode/listing_0038_many_register_mov.asm
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; ========================================================================
;
; (C) Copyright 2023 by Molly Rocket, Inc., All Rights Reserved.
;
; This software is provided 'as-is', without any express or implied
; warranty. In no event will the authors be held liable for any damages
; arising from the use of this software.
;
; Please see https://computerenhance.com for further information
;
; ======================================================================== */
; ========================================================================
; LISTING 38
; ========================================================================
bits 16
mov cx, bx
mov ch, ah
mov dx, bx
mov si, bx
mov bx, di
mov al, cl
mov ch, ch
mov bx, ax
mov bx, si
mov sp, di
mov bp, ax

56
1-reg-reg-decode/main.c
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#include "../common.h"
static void
decode_and_print_reg_reg_movs(u8 *data, u64 size)
{
printf("bits 16\n\n");
/* We do not handle corrupt binaries */
for (u64 i = 0; i < size; i += 2) {
u8 b1 = data[i + 0];
u8 b2 = data[i + 1];
u8 D_flag = (b1 & 0x2) >> 1;
u8 W_flag = b1 & 0x1;
u8 mod = (b2 & 0xC0) >> 6;
u8 reg_field = (b2 & 0x38) >> 3;
u8 rm_field = b2 & 0x7;
const char **regs = W_flag ? REGS_W1 : REGS_W0;
const char **rms = W_flag ? RM_W1 : RM_W0;
if (D_flag) {
/* Instruction destination is specified in REG field */
printf("mov %s, %s\n", regs[reg_field], rms[rm_field]);
} else {
/* Instruction source is specified in REG field */
printf("mov %s, %s\n", rms[rm_field], regs[reg_field]);
}
}
}
int
main(int argc, char **argv)
{
if (argc != 2) {
fprintf(stderr, "Usage: %s binary_file\n", argv[0]);
return(1);
}
char *filename = argv[1];
int fd = open(filename, O_RDONLY);
if (fd == -1) {
perror("open");
return(1);
}
u64 size = file_size(fd);
u8 *data = read_file(fd, size);
decode_and_print_reg_reg_movs(data, size);
return(0);
}

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2-more-decode/listing_0039_more_movs
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2-more-decode/listing_0039_more_movs.asm
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; ========================================================================
;
; (C) Copyright 2023 by Molly Rocket, Inc., All Rights Reserved.
;
; This software is provided 'as-is', without any express or implied
; warranty. In no event will the authors be held liable for any damages
; arising from the use of this software.
;
; Please see https://computerenhance.com for further information
;
; ========================================================================
; ========================================================================
; LISTING 39
; ========================================================================
bits 16
; Register-to-register
mov si, bx
mov dh, al
; 8-bit immediate-to-register
mov cx, 12
mov cx, -12
; 16-bit immediate-to-register
mov dx, 3948
mov dx, -3948
; Source address calculation
mov al, [bx + si]
mov bx, [bp + di]
mov dx, [bp]
; Source address calculation plus 8-bit displacement
mov ah, [bx + si + 4]
; Source address calculation plus 16-bit displacement
mov al, [bx + si + 4999]
; Dest address calculation
mov [bx + di], cx
mov [bp + si], cl
mov [bp], ch

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2-more-decode/listing_0040_challenge_movs
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38
2-more-decode/listing_0040_challenge_movs.asm
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; ========================================================================
;
; (C) Copyright 2023 by Molly Rocket, Inc., All Rights Reserved.
;
; This software is provided 'as-is', without any express or implied
; warranty. In no event will the authors be held liable for any damages
; arising from the use of this software.
;
; Please see https://computerenhance.com for further information
;
; ========================================================================
; ========================================================================
; LISTING 40
; ========================================================================
bits 16
; Signed displacements
mov ax, [bx + di - 37]
mov [si - 300], cx
mov dx, [bx - 32]
; Explicit sizes
mov [bp + di], byte 7
mov [di + 901], word 347
; Direct address
mov bp, [5]
mov bx, [3458]
; Memory-to-accumulator test
mov ax, [2555]
mov ax, [16]
; Accumulator-to-memory test
mov [2554], ax
mov [15], ax

281
2-more-decode/main.c
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#include "../common.h"
static void
print_mov(u8 wide, u8 swap, struct rm dest, struct rm src)
{
const char **regs = wide ? REGS_W1 : REGS_W0;
if (swap) {
struct rm buf = dest;
dest = src;
src = buf;
}
printf("mov ");
/* Dest can not be an immediate, so dest.imm indicates if there's a displacement */
if (dest.reg1 == NO_REGISTER && dest.reg2 == NO_REGISTER && dest.disp != 0) {
printf("[%d]", dest.disp);
} else if (dest.reg2 == NO_REGISTER && dest.imm == 0) {
printf("%s", regs[dest.reg1]);
} else if (dest.reg2 != NO_REGISTER && dest.imm == 0) {
printf("[%s + %s]", REGS_W1[dest.reg1], REGS_W1[dest.reg2]);
} else if (dest.reg2 == NO_REGISTER && dest.imm != 0) {
printf("[%s + %d]", REGS_W1[dest.reg1], dest.disp);
} else if (dest.reg2 != NO_REGISTER && dest.imm != 0) {
printf("[%s + %s + %d]", REGS_W1[dest.reg1], REGS_W1[dest.reg2], dest.disp);
}
printf(", ");
if (src.reg1 == NO_REGISTER) {
if (src.disp == 0) {
printf("%s %d", wide ? "word" : "byte", src.imm); /* only the src can be an immediate */
} else {
printf("[%d]", src.disp);
}
} else {
if (src.reg2 == NO_REGISTER && src.imm == 0) {
printf("%s", regs[src.reg1]);
} else if (src.reg2 != NO_REGISTER && src.imm == 0) {
printf("[%s + %s]", REGS_W1[src.reg1], REGS_W1[src.reg2]);
} else if (src.reg2 == NO_REGISTER && src.imm != 0) {
printf("[%s + %d]", REGS_W1[src.reg1], src.disp);
} else if (src.reg2 != NO_REGISTER && src.imm != 0) {
printf("[%s + %s + %d]", REGS_W1[src.reg1], REGS_W1[src.reg2], src.disp);
}
}
printf("\n");
}
static int
decode_rm(u8 *data, int offset, struct rm *location)
{
int advance = 0;
u8 b2 = data[offset + 1];
u8 mod = (b2 & 0xC0) >> 6;
u8 rm_field = b2 & 0x7;
if (mod == MOD_REGISTER) {
location->reg1 = rm_field;
location->reg2 = -1;
location->disp = 0;
location->imm = 0;
advance = 2;
} else if (mod == MOD_MEMORY) {
s16 b3 = data[offset + 2];
s16 b4 = data[offset + 3];
if (rm_field == 0x6) {
location->reg1 = NO_REGISTER;
location->reg2 = NO_REGISTER;
location->disp = (b4 << 8) | b3;
location->imm = 0;
advance = 4;
} else {
location->reg1 = MOD_PAIRS_FIRST[rm_field];
location->reg2 = MOD_PAIRS_SECOND[rm_field];
location->disp = 0;
location->imm = 1;
advance = 2;
}
} else if (mod == MOD_MEMORY_8) {
s8 b3 = data[offset + 2];
location->reg1 = MOD_PAIRS_FIRST[rm_field];
location->reg2 = MOD_PAIRS_SECOND[rm_field];
location->disp = b3;
location->imm = 1;
advance = 3;
} else if (mod == MOD_MEMORY_16) {
s16 b3 = data[offset + 2];
s16 b4 = data[offset + 3];
location->reg1 = MOD_PAIRS_FIRST[rm_field];
location->reg2 = MOD_PAIRS_SECOND[rm_field];
location->disp = (b4 << 8) | b3;
location->imm = 1;
advance = 4;
}
return(advance);
}
static void
decode_and_print_more_movs(u8 *data, u64 size)
{
printf("bits 16\n\n");
/* We still do not handle corrupt binaries */
u64 offset = 0;
while (offset < size) {
u8 b1 = data[offset + 0];
if ((b1 & MASK_REG_RM) == OPCODE_REG_RM) {
u8 b2 = data[offset + 1];
u8 W_flag = b1 & 0x1;
u8 D_flag = (b1 & 0x2) >> 1;
u8 reg_field = (b2 & 0x38) >> 3;
struct rm dest = { 0 };
struct rm src = { 0 };
dest.reg1 = reg_field;
dest.reg2 = -1;
dest.disp = 0;
dest.imm = 0;
offset += decode_rm(data, offset, &src);
print_mov(W_flag, !D_flag, dest, src);
} else if ((b1 & MASK_IMM_RM) == OPCODE_IMM_RM) {
u8 W_flag = b1 & 0x1;
u8 D_flag = 1; /* Immediate to register-memory always has mod/rm as destination */
struct rm dest = { 0 };
struct rm src = { 0 };
offset += decode_rm(data, offset, &dest);
s16 immediate = 0;
if (W_flag) {
s16 b5 = data[offset];
s16 b6 = data[offset + 1];
immediate = (b6 << 8) | b5;
offset += 2;
} else {
s16 b5 = data[offset];
immediate = b5;
offset += 1;
}
src.reg1 = NO_REGISTER;
src.imm = immediate;
print_mov(W_flag, !D_flag, dest, src);
} else if ((b1 & MASK_IMM_REG) == OPCODE_IMM_REG) {
u8 W_flag = (b1 & 0x8) >> 3;
u16 b2 = data[offset + 1];
u8 reg = b1 & 0x7;
struct rm dest = { 0 };
struct rm src = { 0 };
dest.reg1 = reg;
dest.reg2 = NO_REGISTER;
dest.disp = 0;
dest.imm = 0;
s16 immediate = 0;
if (W_flag) {
/* A 16-bit immediate follows */
u16 b3 = data[offset + 2];
immediate = (b3 << 8) | b2;
offset += 3;
} else {
/* An 8-bit immediate follows */
immediate = b2;
offset += 2;
}
src.reg1 = NO_REGISTER;
src.reg2 = NO_REGISTER;
src.disp = 0;
src.imm = immediate;
print_mov(W_flag, 0, dest, src);
} else if ((b1 & MASK_MEM_ACC) == OPCODE_MEM_ACC) {
u8 W_flag = b1 & 0x1;
u8 b2 = data[offset + 1];
struct rm dest = { 0 };
struct rm src = { 0 };
dest.reg1 = AX;
dest.reg2 = NO_REGISTER;
dest.disp = 0;
dest.imm = 0;
u16 address = 0;
if (W_flag) {
u16 b3 = data[offset + 2];
address = (b3 << 8) | b2;
offset += 3;
} else {
address = b2;
offset += 2;
}
src.reg1 = NO_REGISTER;
src.reg2 = NO_REGISTER;
src.disp = address;
src.imm = 0;
print_mov(W_flag, 0, dest, src);
} else if ((b1 & MASK_ACC_MEM) == OPCODE_ACC_MEM) {
u8 W_flag = b1 & 0x1;
u8 b2 = data[offset + 1];
struct rm dest = { 0 };
struct rm src = { 0 };
dest.reg1 = AX;
dest.reg2 = NO_REGISTER;
dest.disp = 0;
dest.imm = 0;
u16 address = 0;
if (W_flag) {
u16 b3 = data[offset + 2];
address = (b3 << 8) | b2;
offset += 3;
} else {
address = b2;
offset += 2;
}
src.reg1 = NO_REGISTER;
src.reg2 = NO_REGISTER;
src.disp = address;
src.imm = 0;
print_mov(W_flag, 1, dest, src);
}
}
}
int
main(int argc, char **argv)
{
if (argc != 2) {
fprintf(stderr, "Usage: %s binary_file\n", argv[0]);
return(1);
}
char *filename = argv[1];
int fd = open(filename, O_RDONLY);
if (fd == -1) {
perror("open");
return(1);
}
u64 size = file_size(fd);
u8 *data = read_file(fd, size);
decode_and_print_more_movs(data, size);
return(0);
}

12
2-more-decode/test.sh
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#!/bin/bash
for bin_file in listing_0039_more_movs listing_0040_challenge_movs; do
./8086-decode $bin_file > test.asm
nasm test.asm
if ! diff -s test $bin_file; then
echo "Test $bin_file failed!"
exit 1
fi
done
exit 0

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3-arithmetic/listing_0041_add_sub_cmp_jnz
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3-arithmetic/listing_0041_add_sub_cmp_jnz.asm
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; ========================================================================
;
; (C) Copyright 2023 by Molly Rocket, Inc., All Rights Reserved.
;
; This software is provided 'as-is', without any express or implied
; warranty. In no event will the authors be held liable for any damages
; arising from the use of this software.
;
; Please see https://computerenhance.com for further information
;
; ========================================================================
; ========================================================================
; LISTING 41
; ========================================================================
bits 16
add bx, [bx+si]
add bx, [bp]
add si, 2
add bp, 2
add cx, 8
add bx, [bp + 0]
add cx, [bx + 2]
add bh, [bp + si + 4]
add di, [bp + di + 6]
add [bx+si], bx
add [bp], bx
add [bp + 0], bx
add [bx + 2], cx
add [bp + si + 4], bh
add [bp + di + 6], di
add byte [bx], 34
add word [bp + si + 1000], 29
add ax, [bp]
add al, [bx + si]
add ax, bx
add al, ah
add ax, 1000
add al, -30
add al, 9
sub bx, [bx+si]
sub bx, [bp]
sub si, 2
sub bp, 2
sub cx, 8
sub bx, [bp + 0]
sub cx, [bx + 2]
sub bh, [bp + si + 4]
sub di, [bp + di + 6]
sub [bx+si], bx
sub [bp], bx
sub [bp + 0], bx
sub [bx + 2], cx
sub [bp + si + 4], bh
sub [bp + di + 6], di
sub byte [bx], 34
sub word [bx + di], 29
sub ax, [bp]
sub al, [bx + si]
sub ax, bx
sub al, ah
sub ax, 1000
sub al, -30
sub al, 9
cmp bx, [bx+si]
cmp bx, [bp]
cmp si, 2
cmp bp, 2
cmp cx, 8
cmp bx, [bp + 0]
cmp cx, [bx + 2]
cmp bh, [bp + si + 4]
cmp di, [bp + di + 6]
cmp [bx+si], bx
cmp [bp], bx
cmp [bp + 0], bx
cmp [bx + 2], cx
cmp [bp + si + 4], bh
cmp [bp + di + 6], di
cmp byte [bx], 34
cmp word [4834], 29
cmp ax, [bp]
cmp al, [bx + si]
cmp ax, bx
cmp al, ah
cmp ax, 1000
cmp al, -30
cmp al, 9
test_label0:
jnz test_label1
jnz test_label0
test_label1:
jnz test_label0
jnz test_label1
label:
je label
jl label
jle label
jb label
jbe label
jp label
jo label
js label
jne label
jnl label
jg label
jnb label
ja label
jnp label
jno label
jns label
loop label
loopz label
loopnz label
jcxz label

349
3-arithmetic/main.c
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#include "../common.h"
static void
print_inst(int instruction_offset, struct instruction *inst, int *labels, int label_count)
{
if (inst->opcode > 0xF) {
for (int i = 0; i < label_count; ++i) {
if (instruction_offset + inst->size + inst->jump_offset == labels[i]) {
printf("%s label_%d\n", OP_NAMES[inst->opcode], i);
return;
}
}
CRASH_SHOULDNOT();
}
const char **regs = inst->wide ? REGS_W1 : REGS_W0;
struct rm dest = inst->dst;
struct rm src = inst->src;
if (inst->swap) {
struct rm buf = dest;
dest = src;
src = buf;
}
printf("%s ", OP_NAMES[inst->opcode]);
/* Dest can not be an immediate, so dest.imm indicates if there's a displacement */
if (dest.reg1 == NO_REGISTER && dest.reg2 == NO_REGISTER && dest.disp != 0) {
printf("[%d]", dest.disp);
} else if (dest.reg2 == NO_REGISTER && dest.imm == 0) {
printf("%s", regs[dest.reg1]);
} else if (dest.reg2 != NO_REGISTER && dest.imm == 0) {
printf("[%s + %s]", REGS_W1[dest.reg1], REGS_W1[dest.reg2]);
} else if (dest.reg2 == NO_REGISTER && dest.imm != 0) {
printf("[%s + %d]", REGS_W1[dest.reg1], dest.disp);
} else if (dest.reg2 != NO_REGISTER && dest.imm != 0) {
printf("[%s + %s + %d]", REGS_W1[dest.reg1], REGS_W1[dest.reg2], dest.disp);
}
printf(", ");
if (src.reg1 == NO_REGISTER) {
if (src.disp == 0) {
printf("%s %d", inst->wide ? "word" : "byte", src.imm); /* only the src can be an immediate */
} else {
printf("[%d]", src.disp);
}
} else {
if (src.reg2 == NO_REGISTER && src.imm == 0) {
printf("%s", regs[src.reg1]);
} else if (src.reg2 != NO_REGISTER && src.imm == 0) {
printf("[%s + %s]", REGS_W1[src.reg1], REGS_W1[src.reg2]);
} else if (src.reg2 == NO_REGISTER && src.imm != 0) {
printf("[%s + %d]", REGS_W1[src.reg1], src.disp);
} else if (src.reg2 != NO_REGISTER && src.imm != 0) {
printf("[%s + %s + %d]", REGS_W1[src.reg1], REGS_W1[src.reg2], src.disp);
}
}
printf("\n");
}
static int
decode_rm(u8 *data, int offset, struct rm *location)
{
int advance = 0;
u8 b2 = data[offset + 1];
u8 mod = (b2 & 0xC0) >> 6;
u8 rm_field = b2 & 0x7;
if (mod == MOD_REGISTER) {
location->reg1 = rm_field;
location->reg2 = -1;
location->disp = 0;
location->imm = 0;
advance = 2;
} else if (mod == MOD_MEMORY) {
s16 b3 = data[offset + 2];
s16 b4 = data[offset + 3];
if (rm_field == 0x6) {
location->reg1 = NO_REGISTER;
location->reg2 = NO_REGISTER;
location->disp = (b4 << 8) | b3;
location->imm = 0;
advance = 4;
} else {
location->reg1 = MOD_PAIRS_FIRST[rm_field];
location->reg2 = MOD_PAIRS_SECOND[rm_field];
location->disp = 0;
location->imm = 1;
advance = 2;
}
} else if (mod == MOD_MEMORY_8) {
s8 b3 = data[offset + 2];
location->reg1 = MOD_PAIRS_FIRST[rm_field];
location->reg2 = MOD_PAIRS_SECOND[rm_field];
location->disp = b3;
location->imm = 1;
advance = 3;
} else if (mod == MOD_MEMORY_16) {
s16 b3 = data[offset + 2];
s16 b4 = data[offset + 3];
location->reg1 = MOD_PAIRS_FIRST[rm_field];
location->reg2 = MOD_PAIRS_SECOND[rm_field];
location->disp = (b4 << 8) | b3;
location->imm = 1;
advance = 4;
}
return(advance);
}
static int
decode_and_print_add_sub_cmp_jmp(u8 *data, u64 size, struct instruction *stream)
{
printf("bits 16\n\n");
/* We still do not handle corrupt binaries */
u64 offset = 0;
int stream_at = 0;
while (offset < size) {
int saved_offset = offset;
u8 b1 = data[offset + 0];
u8 b2 = data[offset + 1];
u8 antiop = b1 & ANTIOP_MASK;
u8 op = 0;
if (antiop == 0x00 || antiop == 0x4) {
op = (b1 & 0x38) >> 3;
} else {
op = (b2 & 0x38) >> 3;
}
if (antiop == 0x00) {
u8 W_flag = b1 & 0x1;
u8 D_flag = (b1 & 0x2) >> 1;
u8 reg_field = (b2 & 0x38) >> 3;
struct rm dest = { 0 };
struct rm src = { 0 };
dest.reg1 = reg_field;
dest.reg2 = -1;
dest.disp = 0;
dest.imm = 0;
offset += decode_rm(data, offset, &src);
struct instruction inst = {
.size = offset - saved_offset,
.opcode = op,
.dst = dest,
.src = src,
.wide = W_flag,
.swap = !D_flag
};
stream[stream_at++] = inst;
continue;
} else if (antiop == 0x80) {
u8 W_flag = b1 & 0x1;
u8 S_flag = (b1 & 0x2) >> 1;
u8 D_flag = 1; /* Immediate to register-memory always has mod/rm as destination */
struct rm dest = { 0 };
struct rm src = { 0 };
offset += decode_rm(data, offset, &dest);
s16 immediate = 0;
if (S_flag && !W_flag) {
s16 b5 = data[offset];
s16 b6 = data[offset + 1];
immediate = (b6 << 8) | b5;
offset += 2;
} else {
s16 b5 = data[offset];
immediate = b5;
offset += 1;
}
src.reg1 = NO_REGISTER;
src.imm = immediate;
struct instruction inst = {
.size = offset - saved_offset,
.opcode = op,
.dst = dest,
.src = src,
.wide = W_flag,
.swap = !D_flag
};
stream[stream_at++] = inst;
continue;
} else if (antiop == 0x4) {
u8 W_flag = b1 & 0x1;
s16 immediate = 0;
struct rm dest = { 0 };
struct rm src = { 0 };
dest.reg1 = AX;
dest.reg2 = NO_REGISTER;
dest.disp = 0;
dest.imm = 0;
if (W_flag) {
s16 b3 = data[offset + 2];
immediate= (b3 << 8) | b2;
offset += 3;
} else {
immediate = b2;
offset += 2;
}
src.reg1 = NO_REGISTER;
src.reg2 = NO_REGISTER;
src.disp = 0;
src.imm = immediate;
struct instruction inst = {
.size = offset - saved_offset,
.opcode = op,
.dst = dest,
.src = src,
.wide = W_flag,
.swap = 0,
};
stream[stream_at++] = inst;
continue;
}
offset += 2;
struct instruction inst = {
.size = offset - saved_offset,
.opcode = b1,
.jump_offset = (s8) b2
};
stream[stream_at++] = inst;
}
return(stream_at);
}
static int
insert_labels(struct instruction *in_stream, int instruction_count, int *labels)
{
int instruction_offset = 0;
int label_count = 0;
for (int i = 0; i < instruction_count; ++i) {
struct instruction *inst = in_stream + i;
if (inst->opcode > 0xF) {
/* jmp-like */
int target = instruction_offset + inst->size + inst->jump_offset;
int label_exists = 0;
for (int j = 0; j < label_count; ++j) {
if (labels[j] == target) {
label_exists = 1;
break;
}
}
if (!label_exists) {
labels[label_count++] = target;
}
}
instruction_offset += inst->size;
}
return(label_count);
}
static void
print_instruction_stream(struct instruction *stream, int instruction_count,
int *labels, int label_count)
{
int instruction_offset = 0;
for (int i = 0; i < instruction_count; ++i) {
struct instruction *inst = stream + i;
for (int j = 0; j < label_count; ++j) {
if (labels[j] == instruction_offset) {
printf("label_%d:\n", j);
break;
}
}
print_inst(instruction_offset, stream + i, labels, label_count);
instruction_offset += inst->size;
}
}
int
main(int argc, char **argv)
{
if (argc != 2) {
fprintf(stderr, "Usage: %s binary_file\n", argv[0]);
return(1);
}
char *filename = argv[1];
int fd = open(filename, O_RDONLY);
if (fd == -1) {
perror("open");
return(1);
}
u64 size = file_size(fd);
u8 *data = read_file(fd, size);
struct instruction stream[MAX_INSTRUCTIONS] = { 0 };
int labels[MAX_LABELS] = { 0 };
int instruction_count = decode_and_print_add_sub_cmp_jmp(data, size, stream);
int label_count = insert_labels(stream, instruction_count, labels);
print_instruction_stream(stream, instruction_count, labels, label_count);
return(0);
}

166
common.h
Unescape View File

@ -0,0 +1,166 @@
#include <stdint.h> /* uint32_t etc */
#include <stdlib.h> /* exit */
#include <stdio.h> /* perror, fprintf */
#include <fcntl.h> /* open */
#include <unistd.h> /* read */
#include <sys/stat.h> /* fstat */
typedef uint8_t u8;
typedef uint16_t u16;
typedef uint32_t u32;
typedef uint64_t u64;
typedef int8_t s8;
typedef int16_t s16;
typedef int32_t s32;
typedef int64_t s64;
#define MAX_INSTRUCTIONS 1024
#define MAX_LABELS 128
enum regs_w {
AX = 0,
CX = 1,
DX = 2,
BX = 3,
SP = 4,
BP = 5,
SI = 6,
DI = 7,
};
enum regs_h {
AL = 0,
CL = 1,
DL = 2,
BL = 3,
AH = 4,
CH = 5,
DH = 6,
BH = 7,
};
enum mov_mod {
MOD_MEMORY = 0x00,
MOD_MEMORY_8 = 0x01,
MOD_MEMORY_16 = 0x02,
MOD_REGISTER = 0x03,
};
enum mov_opcode {
OPCODE_REG_RM = 0x88,
OPCODE_IMM_RM = 0xC6,
OPCODE_IMM_REG = 0xB0,
OPCODE_MEM_ACC = 0xA0,
OPCODE_ACC_MEM = 0xA2,
};
enum mov_opcode_mask {
MASK_REG_RM = 0xFC,
MASK_IMM_RM = 0xFE,
MASK_IMM_REG = 0xF0,
MASK_MEM_ACC = 0xFE,
MASK_ACC_MEM = 0xFE,
MASK_ADD_SUB_CMP = 0xFC,
};
struct rm {
s8 reg1; // -1 here means it's an immediate
s8 reg2; // -1 means no second
s16 disp; // 0 means no displacement
s16 imm; // if it's not an immediate - imm indicates if there is a displacement
};
struct instruction {
u8 size;
u8 opcode;
u8 wide;
u8 swap;
/* for mov, add, sub, cmp */
struct rm dst;
struct rm src;
/* for control-flow instructions */
s8 jump_offset;
};
static const s8 NO_REGISTER = -1;
static const u8 ANTIOP_MASK = 0xC4;
static const char *REGS_W0[] = { "al", "cl", "dl", "bl", "ah", "ch", "dh", "bh" };
static const char *REGS_W1[] = { "ax", "cx", "dx", "bx", "sp", "bp", "si", "di" };
static const s8 MOD_PAIRS_FIRST[] = { BX, BX, BP, BP, SI, DI, BP, BX };
static const s8 MOD_PAIRS_SECOND[] = { SI, DI, SI, DI, NO_REGISTER, NO_REGISTER, NO_REGISTER, NO_REGISTER };
static const char *OP_NAMES[] = {
[0x0] = "add",
[0x5] = "sub",
[0x7] = "cmp",
[0xF] = "mov", /* Source? I made it up */
[0x74] = "je",
[0x7C] = "jl",
[0x7E] = "jle",
[0x72] = "jb",
[0x76] = "jbe",
[0x7A] = "jp",
[0x70] = "jo",
[0x78] = "js",
[0x75] = "jne",
[0x7D] = "jnl",
[0x7F] = "jg",
[0x73] = "jnb",
[0x77] = "ja",
[0x7B] = "jnp",
[0x71] = "jno",
[0x79] = "jns",
[0xE2] = "loop",
[0xE1] = "loopz",
[0xE0] = "loopnz",
[0xE3] = "jcxz",
};
#define CRASH_NOTIMPL() do { fprintf(stderr, "line: %d. not implemented\n", __LINE__); exit(1); } while (0)
#define CRASH_SHOULDNOT() do { fprintf(stderr, "line: %d. should not happen\n", __LINE__); exit(1); } while (0)
static u64
file_size(int fd)
{
struct stat st = { 0 };
if (fstat(fd, &st) == -1) {
perror("fstat");
exit(1);
}
return(st.st_size);
}
static u8 *
read_file(int fd, u64 size)
{
u8 *buf = malloc(size);
if (!buf) {
perror("malloc");
exit(1);
}
int rt = read(fd, buf, size);
if (rt == -1) {
perror("read");
exit(1);
}
if (rt != (int) size) {
fprintf(stderr, "short read: %d < %lu\n", rt, size);
exit(1);
}
return(buf);
}
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