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Part01-02: Immedate to register/memory wip, moved EAC from r/m map to function

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Joseph Ferano 2024-01-14 11:37:37 +07:00
parent 9b1d8d4005
commit 9f7e371a49
1 changed files with 54 additions and 33 deletions
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87
decode.c
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@ -52,6 +52,43 @@ char* memory[65536];
// void inst_mov_rgmm_reg()
/// Get Effective Address Calculation Registers
char* get_eac_registers(char rm)
{
char *reg_name;
switch (rm)
{
case 0b000:
reg_name = "bx + si";
break;
case 0b001:
reg_name = "bx + di";
break;
case 0b010:
reg_name = "bp + si";
break;
case 0b011:
reg_name = "bp + di";
break;
case 0b100:
reg_name = "si";
break;
case 0b101:
reg_name = "di";
break;
case 0b110:
reg_name = "bp";
break;
case 0b111:
reg_name = "bx";
break;
default:
perror("Invalid R/M value");
exit(1);
}
return reg_name;
}
int main(int argc, char** argv)
{
if (argc < 2)
@ -108,34 +145,7 @@ int main(int argc, char** argv)
{
dst_name = w == 1 ? src_reg.fullname : src_reg.bytename;
}
char* src_name;
switch (rm)
{
case 0b000:
src_name = "bx + si";
break;
case 0b001:
src_name = "bx + di";
break;
case 0b010:
src_name = "bp + si";
break;
case 0b011:
src_name = "bp + di";
break;
case 0b100:
src_name = "si";
break;
case 0b101:
src_name = "di";
break;
case 0b110:
src_name = "bp";
break;
case 0b111:
src_name = "bx";
break;
}
char* src_name = get_eac_registers(rm);
if (mod == MODE_MEM_DIS_16)
{
bytes_read = fread(buf, sizeof(char), 2, f);
@ -148,10 +158,6 @@ int main(int argc, char** argv)
{
printf("mov [%s], %s ;(mod %d, w %d, d %d)", src_name, dst_name, mod, d, w);
}
char disp_lo = buf[0];
char disp_hi = buf[1];
(void)disp_lo;
(void)disp_hi;
}
else if (mod == MODE_MEM_DIS_08)
{
@ -181,7 +187,22 @@ int main(int argc, char** argv)
// Immediate to register/memory
else if ((inst & ~0x1) == (char)0b11000110)
{
printf("mov imm to reg/mem");
char w = inst & 0b00000001;
bytes_read = fread(buf, sizeof(char), 1, f);
char mod = (buf[0] & 0b11000000) >> 6;
char rm = (buf[0] & 0b00000111);
int bytes_to_read = 1;
bytes_to_read += w == 0 ? 0 : 1;
// This is a trick because mod == 1 and mod == 2 will displace one and two bytes
// respectively but mod == 3 wraps to 0 since it doesn't displace
bytes_to_read += mod % 3;
bytes_read = fread(buf, sizeof(char), bytes_to_read, f);
char *eac_name = get_eac_registers(rm);
char *data_ptr = (char*)buf + (char)bytes_to_read - (w == 0 ? 1 : 2);
i16 data = w == 0 ? data_ptr[0] : (i16)data_ptr[1] << 8 | data_ptr[0];
char *word = w == 0 ? "byte" : "word";
char *disp = mod == 1 || mod == 2 ? sprintf();
printf("mov [%s], %s %d w %d mod %d rm %d", eac_name, word, data, w, mod, rm);
}
// Immediate to register
else if ((inst & ~0xF) == (char)0b10110000)