Turingon/8080-Emulator
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This commit is contained in:
Luxdragon 2024-01-06 22:23:36 +01:00
parent 1d5d33a613
commit ee40bed389
1 changed files with 62 additions and 6 deletions
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68
emulator_shell.c
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@ -1,5 +1,10 @@
#include <stdio.h>
#include <stdint.h> // for the uintx_t's
#include "disassembler.c"
// gcc emulator_shell.c disassembler.c -o disassembler
int disassemble8080(buffer* b, int pc);
typedef struct ConditionCodes {
@ -73,20 +78,58 @@ int emulate8080(State8080* state) {
uint32_t res = h1 + bc;
state->h = (res & 0xff) >> 8;
state->l = res & 0xff;
state->cc.cy = ((res > 0xffff) > 0);
state->cc.cy = ((res & 0xffff0000) > 0);
break;
case 0x0d: // DCR C
uint8_t res = state->c - 1;
state->c = res;
state->cc.z = (res == 0);
state->cc.s = ((res & 0x80) != 0);
state->cc.p = parity(res, 8);
break;
case 0x0e: // MVI C, byte
state->c = opcode[1];
state->pc += 1;
break;
case 0x0f: // RRC
uint8_t x = state->a;
state->a = ((x & 1) << 7) | (x >> 1);
state->cc.cy = (1 == (x & 1));
break;
case 0x11: // LXI D, word
state->d = opcode[2];
state->e = opcode[1];
state->pc += 2;
case 0x13: // INX D
state->e++;
if (state->e == 0) {
state->d++;
}
break;
case 0x19: // DAD D
uint32_t h1 = (state->h << 8) | state->l;
uint32_t de = (state->d << 8) | state->e;
uint32_t res = h1 + de;
state->h = (res & 0xff) >> 8;
state->l = res & 0xff;
state->cc.cy = ((res & 0xffff0000) != 0);
break;
case 0x1a: // LDAX D
uint16_t de = (state->d << 8) | state->e;
state->a = state->memory[de];
break;
case 0x21: // LXI H, word
state->h = opcode[2];
state->l = opcode[1];
state->pc += 2;
case 0x23: // INX H
state->l++;
if (state->l == 0) {
state->h++;
}
break;
case 0x26: // MVI H, byte
state->h = opcode[1];
state->pc += 1;
@ -186,11 +229,7 @@ int emulate8080(State8080* state) {
state->pc++;
break;
case 0x0f: // RRC
uint8_t x = state->a;
state->a = ((x & 1) << 7) | (x >> 1);
state->cc.cy = (1 == (x & 1));
break;
case 0x1f: // RAR
uint8_t x = state->a;
@ -198,6 +237,23 @@ int emulate8080(State8080* state) {
state->cc.cy = (1 == (x & 1));
break;
case 0xf1: // POP PSW
state->a = state->memory[state->sp+1];
uint8_t psw = state->memory[state->sp];
state->cc.z = (0x01 == (psw & 0x01));
state->cc.s = (0x02 == (psw & 0x02));
state->cc.p = (0x04 == (psw & 0x04));
state->cc.cy = (0x08 == (psw & 0x08));
state->cc.ac = (0x10 == (psw & 0x10));
state->sp += 2;
break;
case 0xf5: // PUSH PSW
state->memory[state->sp-1] = state->a;
state->memory[state->sp-2] = (state->cc.z | (state->cc.s << 1) | (state->cc.p << 2) | (state->cc.cy << 3) | (state->cc.ac << 4));
state->sp -= 2;
break;
case 0xfe: // CPI byte
uint8_t x = state->a - opcode[1];
state->cc.z = (x == 0);