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NEC INS/EXT instructions (#9)

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Cacodemon345
2022-09-05 16:18:10 +06:00
committed by GitHub
parent cc72ab21e8
commit 323f7e7a62
1 changed files with 48 additions and 0 deletions
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48
src/cpu/808x.c
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@@ -1824,6 +1824,54 @@ execx86(int cycs)
handled = 1;
break;
}
case 0x31: /* INS reg1, reg2 */
case 0x39: /* INS reg8, imm4 */
{
do_mod_rm();
wait(1, 0);
{
uint8_t bit_length = ((opcode & 0x8) ? (pfq_fetchb() & 0xF) : (getr8(cpu_reg) & 0xF)) + 1;
uint8_t bit_offset = getr8(cpu_rm) & 0xF;
uint32_t byteaddr = (ES << 4) + DI;
uint32_t i = 0;
if (bit_offset >= 8) { DI++; byteaddr++; bit_offset -= 8; }
for (i = 0; i < bit_length; i++) {
byteaddr = (ES << 4) + DI;
writememb(ES << 4, DI, (read_mem_b(byteaddr) & ~(1 << (bit_offset))) | ((!!(AX & (1 << i))) << bit_offset));
bit_offset++;
if (bit_offset == 8) { DI++; bit_offset = 0; }
}
setr8(cpu_rm, bit_offset);
}
handled = 1;
break;
}
case 0x33: /* EXT reg1, reg2 */
case 0x3b: /* EXT reg8, imm4 */
{
do_mod_rm();
wait(1, 0);
{
uint8_t bit_length = ((opcode & 0x8) ? (pfq_fetchb() & 0xF) : (getr8(cpu_reg) & 0xF)) + 1;
uint8_t bit_offset = getr8(cpu_rm) & 0xF;
uint32_t byteaddr = (DS << 4) + SI;
uint32_t i = 0;
if (bit_offset >= 8) { SI++; byteaddr++; bit_offset -= 8; }
AX = 0;
for (i = 0; i < bit_length; i++) {
byteaddr = (DS << 4) + SI;
AX |= (!!(readmemb(byteaddr) & (1 << bit_offset))) << i;
bit_offset++;
if (bit_offset == 8) { SI++; bit_offset = 0; }
}
setr8(cpu_rm, bit_offset);
}
handled = 1;
break;
}
default: {
opcode = orig_opcode;
break;