7 u8int s[16], ipage, intm, z80irq;
9 u16int spc, scurpc, sp;
20 enum { rB, rC, rD, rE, rH, rL, rHL, rA, rF = rHL };
21 #define BC() (s[rB] << 8 | s[rC])
22 #define DE() (s[rD] << 8 | s[rE])
23 #define HL() (s[rH] << 8 | s[rL])
28 return z80read(spc++);
37 return u | z80read(spc++) << 8;
49 z80write(--sp, u >> 8);
65 return v | z80read(sp++) << 8;
71 return z80read(n) | z80read(n+1) << 8;
75 write16(u16int n, u16int v)
84 return (((v * 0x0101010101010101ULL) & 0x8040201008040201ULL) % 0x1FF) & 1;
88 move(u8int dst, u8int src)
95 z80write(HL(), s[src]);
99 s[dst] = z80read(HL());
107 alu(u8int op, u8int n)
115 case 8: u = fetch8(); t = 3; break;
116 case 10: u = ix[0]; t = 4; break;
117 case 11: u = ix[1]; t = 4; break;
118 case 12: u = ix[0] >> 8; t = 4; break;
119 case 13: u = ix[1] >> 8; t = 4; break;
120 case 14: u = z80read(ix[0] + fetch8()); t = 15; break;
121 case 15: u = z80read(ix[1] + fetch8()); t = 15; break;
133 v4 = (s[rA] & 0x0f) + (u & 0x0f);
137 v4 = (s[rA] & 0x0f) + (u & 0x0f) + (s[rF] & 1);
138 v = s[rA] + u + (s[rF] & 1);
142 v4 = (s[rA] & 0x0f) + (~u & 0x0f) + 1;
143 v = s[rA] + (u ^ 0xff) + 1;
146 v4 = (s[rA] & 0x0f) + (~u & 0x0f) + (~s[rF] & 1);
147 v = s[rA] + (u ^ 0xff) + (~s[rF] & 1);
149 case 4: v = s[rA] & u; break;
150 case 5: v = s[rA] ^ u; break;
151 case 6: v = s[rA] | u; break;
163 if((~(s[rA] ^ u) & (s[rA] ^ v) & 0x80) != 0)
165 }else if(op < 4 || op == 7){
171 if(((s[rA] ^ u) & (s[rA] ^ v) & 0x80) != 0)
185 branch(int cc, int t)
216 s[rF] = s[rF] & FLAGC | FLAGN;
233 s[rF] &= ~(FLAGN|FLAGC|FLAGH);
235 if((v & 0x10000) != 0)
237 if((HL() & 0xfff) + (u & 0xfff) >= 0x1000)
249 v = HL() + u + (s[rF] & FLAGC);
250 v4 = (HL() & 0xfff) + (u & 0xfff) + (s[rF] & FLAGC);
252 if((v & 0x10000) != 0)
254 if((v4 & 0x1000) != 0)
258 if((v & 0x8000) != 0)
260 if((~(HL() ^ u) & (HL() ^ v) & 0x8000) != 0)
271 v = HL() + (u16int)~u + (~s[rF] & FLAGC);
272 v4 = (HL() & 0xfff) + (~u & 0xfff) + (~s[rF] & FLAGC);
274 if((v & 0x10000) == 0)
276 if((v4 & 0x1000) == 0)
280 if((v & 0x8000) != 0)
282 if(((HL() ^ u) & (HL() ^ v) & 0x8000) != 0)
289 addindex(int n, u16int u)
293 s[rF] &= ~(FLAGN|FLAGC|FLAGH);
295 if((v & 0x10000) != 0)
297 if((ix[n] & 0xfff) + (u & 0xfff) >= 0x1000)
315 call(u16int a, int cc)
337 u8int op, v, n, m, c;
343 a = ix[i] + fetch8();
364 default: s[rF] = v >> 7; v = v << 1 | v >> 7; break;
365 case 1: s[rF] = v & 1; v = v >> 1 | v << 7; break;
366 case 2: s[rF] = v >> 7; v = v << 1 | c; break;
367 case 3: s[rF] = v & 1; v = v >> 1 | c << 7; break;
368 case 4: s[rF] = v >> 7; v = v << 1; break;
369 case 5: s[rF] = v & 1; v = v & 0x80 | v >> 1; break;
370 case 6: s[rF] = v >> 7; v = v << 1 | 1; break;
371 case 7: s[rF] = v & 1; v >>= 1; break;
381 s[rF] = s[rF] & ~(FLAGN|FLAGZ) | FLAGH;
406 case 0xa0: case 0xa1: case 0xa8: case 0xa9:
407 case 0xb0: case 0xb1: case 0xb8: case 0xb9:
410 z80write(DE(), z80read(HL()));
411 s[rF] &= ~(FLAGN|FLAGH);
417 s[rF] = s[rF] & ~(FLAGS|FLAGZ|FLAGH) | FLAGN;
423 if((s[rA] & 0xf) < (u & 0xf))
428 if((op & 3) == 0 && s[rE]-- == 0)
433 if((op & 3) == 0 && ++s[rE] == 0)
440 if((s[rC] | s[rB]) != 0){
442 if((op & 0x10) != 0 && l){
449 case 0x42: sbchl(BC()); return 15;
450 case 0x52: sbchl(DE()); return 15;
451 case 0x62: sbchl(HL()); return 15;
452 case 0x72: sbchl(sp); return 15;
453 case 0x43: write16(fetch16(), BC()); return 20;
454 case 0x53: write16(fetch16(), DE()); return 20;
455 case 0x63: write16(fetch16(), HL()); return 20;
456 case 0x73: write16(fetch16(), sp); return 20;
464 if((s[rA] & 0x80) != 0)
468 if((s[rA] & 0xf) != 0)
471 case 0x46: intm &= 0xc0; return 8;
472 case 0x56: intm = intm & 0xc0 | 1; return 8;
473 case 0x47: ipage = s[rA]; return 9;
474 case 0x57: s[rA] = ipage; return 9;
477 z80write(HL(), v >> 4 | s[rA] << 4);
478 s[rA] = s[rA] & 0xf0 | v & 0x0f;
482 z80write(HL(), v << 4 | s[rA] & 0xf);
483 s[rA] = s[rA] & 0xf0 | v >> 4;
488 if((s[rA] & 0x80) != 0)
493 case 0x4a: adchl(BC()); return 15;
494 case 0x5a: adchl(DE()); return 15;
495 case 0x6a: adchl(HL()); return 15;
496 case 0x7a: adchl(sp); return 15;
497 case 0x4b: a = fetch16(); s[rC] = z80read(a++); s[rB] = z80read(a); return 20;
498 case 0x5b: a = fetch16(); s[rE] = z80read(a++); s[rD] = z80read(a); return 20;
499 case 0x6b: a = fetch16(); s[rL] = z80read(a++); s[rH] = z80read(a); return 20;
500 case 0x7b: sp = read16(fetch16()); return 20;
501 case 0x4d: spc = pop16(); return 14;
502 case 0x5e: intm = intm & 0xc0 | 2; return 8;
505 sysfatal("undefined z80 opcode ed%.2x at pc=%#.4x", op, scurpc);
517 case 0x40: case 0x41: case 0x42: case 0x43: case 0x47:
518 case 0x48: case 0x49: case 0x4a: case 0x4b: case 0x4f:
519 case 0x50: case 0x51: case 0x52: case 0x53: case 0x57:
520 case 0x58: case 0x59: case 0x5a: case 0x5b: case 0x5f:
521 case 0x78: case 0x79: case 0x7a: case 0x7b: case 0x7f:
522 s[op >> 3 & 7] = s[op & 7];
524 case 0x60: case 0x61: case 0x62: case 0x63: case 0x67:
525 ix[n] = ix[n] & 0xff | s[op & 7] << 8;
527 case 0x68: case 0x69: case 0x6a: case 0x6b: case 0x6f:
528 ix[n] = ix[n] & 0xff00 | s[op & 7];
530 case 0x65: ix[n] = ix[n] << 8 | ix[n] & 0xff; return 8;
531 case 0x6c: ix[n] = ix[n] >> 8 | ix[n] & 0xff00; return 8;
532 case 0x64: case 0x6d: return 8;
533 case 0x70: case 0x71: case 0x72: case 0x73:
534 case 0x74: case 0x75: case 0x77:
535 z80write(ix[n] + fetch8(), s[op & 7]);
537 case 0x44: case 0x4c: case 0x54: case 0x5c: case 0x7c:
538 s[op >> 3 & 7] = ix[n] >> 8;
540 case 0x45: case 0x4d: case 0x55: case 0x5d: case 0x7d:
541 s[op >> 3 & 7] = ix[n];
543 case 0x46: case 0x4e: case 0x56: case 0x5e: case 0x66: case 0x6e: case 0x7e:
544 s[op >> 3 & 7] = z80read(ix[n] + fetch8());
546 case 0x84: case 0x8c: case 0x94: case 0x9c:
547 case 0xa4: case 0xac: case 0xb4: case 0xbc:
548 return alu(op >> 3 & 7, 12 + n);
549 case 0x85: case 0x8d: case 0x95: case 0x9d:
550 case 0xa5: case 0xad: case 0xb5: case 0xbd:
551 return alu(op >> 3 & 7, 10 + n);
552 case 0x86: case 0x8e: case 0x96: case 0x9e:
553 case 0xa6: case 0xae: case 0xb6: case 0xbe:
554 return alu(op >> 3 & 7, 14 + n);
556 case 0x21: ix[n] = fetch16(); return 14;
557 case 0xe1: ix[n] = pop16(); return 14;
558 case 0x22: write16(fetch16(), ix[n]); return 20;
559 case 0x23: ix[n]++; return 10;
560 case 0xe3: v = ix[n]; ix[n] = read16(sp); write16(sp, v); return 23;
561 case 0x24: inc(ix[n] >> 8); ix[n] += 0x100; return 8;
562 case 0x34: v = ix[n] + fetch8(); z80write(v, inc(z80read(v))); return 23;
563 case 0x25: dec(ix[n] >> 8); ix[n] -= 0x100; return 8;
564 case 0x35: v = ix[n] + fetch8(); z80write(v, dec(z80read(v))); return 23;
565 case 0xe5: push16(ix[n]); return 15;
566 case 0x26: ix[n] = ix[n] & 0xff | fetch8() << 8; return 11;
567 case 0x36: v = ix[n] + fetch8(); z80write(v, fetch8()); return 19;
568 case 0x09: return addindex(n, BC());
569 case 0x19: return addindex(n, DE());
570 case 0x29: return addindex(n, ix[n]);
571 case 0x39: return addindex(n, sp);
572 case 0xe9: spc = ix[n]; return 8;
573 case 0xf9: sp = ix[n]; return 10;
574 case 0x2a: ix[n] = read16(fetch16()); return 20;
575 case 0x2b: ix[n]--; return 10;
576 case 0xcb: return bits(n);
577 case 0x2c: inc(ix[n]++); return 8;
578 case 0x2d: dec(ix[n]--); return 8;
579 case 0x2e: ix[n] = ix[n] & 0xff00 | fetch8(); return 11;
581 sysfatal("undefined z80 opcode %.2x%.2x at pc=%#.4x", n ? 0xfd : 0xdd, op, scurpc);
591 if((z80bus & RESET) != 0){
597 if((z80bus & BUSACK) != 0){
598 if((z80bus & BUSREQ) == 0)
602 if((z80bus & BUSREQ) != 0){
606 if(z80irq != 0 && (intm & 0x80) != 0){
614 sysfatal("z80 interrupt in mode %d", intm & 3);
619 print("%x AF %.2x%.2x BC %.2x%.2x DE %.2x%.2x HL %.2x%.2x IX %.4x IY %.4x\n", scurpc, s[rA], s[rF], s[rB], s[rC], s[rD], s[rE], s[rH], s[rL], ix[0], ix[1]);
622 case 1: return move(op >> 3 & 7, op & 7);
623 case 2: return alu(op >> 3 & 7, op & 7);
627 case 0x10: return branch(--s[rB] != 0, 1);
628 case 0x20: return branch((s[rF] & FLAGZ) == 0, 0);
629 case 0x30: return branch((s[rF] & FLAGC) == 0, 0);
630 case 0x01: s[rC] = fetch8(); s[rB] = fetch8(); return 10;
631 case 0x11: s[rE] = fetch8(); s[rD] = fetch8(); return 10;
632 case 0x21: s[rL] = fetch8(); s[rH] = fetch8(); return 10;
633 case 0x31: sp = fetch16(); return 10;
634 case 0x02: z80write(BC(), s[rA]); return 7;
635 case 0x12: z80write(DE(), s[rA]); return 7;
636 case 0x22: v = fetch16(); z80write(v++, s[rL]); z80write(v, s[rH]); return 16;
637 case 0x32: z80write(fetch16(), s[rA]); return 13;
638 case 0x03: if(++s[rC] == 0) s[rB]++; return 6;
639 case 0x13: if(++s[rE] == 0) s[rD]++; return 6;
640 case 0x23: if(++s[rL] == 0) s[rH]++; return 6;
641 case 0x33: sp++; return 6;
642 case 0x04: inc(s[rB]++); return 4;
643 case 0x14: inc(s[rD]++); return 4;
644 case 0x24: inc(s[rH]++); return 4;
645 case 0x34: z80write(HL(), inc(z80read(HL()))); return 11;
646 case 0x05: dec(s[rB]--); return 4;
647 case 0x15: dec(s[rD]--); return 4;
648 case 0x25: dec(s[rH]--); return 4;
649 case 0x35: z80write(HL(), dec(z80read(HL()))); return 11;
650 case 0x06: s[rB] = fetch8(); return 7;
651 case 0x16: s[rD] = fetch8(); return 7;
652 case 0x26: s[rH] = fetch8(); return 7;
653 case 0x36: z80write(HL(), fetch8()); return 10;
655 s[rF] = s[rF] & ~(FLAGC|FLAGN|FLAGH) | s[rA] >> 7;
656 s[rA] = s[rA] << 1 | s[rA] >> 7;
660 s[rF] = s[rF] & ~(FLAGC|FLAGN|FLAGH) | s[rA] >> 7;
661 s[rA] = s[rA] << 1 | v;
664 if(s[rA] > 0x99 || (s[rF] & FLAGC) != 0){
671 if((s[rA] & 0xf) > 9 || (s[rF] & FLAGH) != 0)
674 if((s[rF] & FLAGN) != 0)
678 s[rF] &= ~(FLAGV|FLAGS|FLAGZ|FLAGH);
679 if(((s[rA] ^ w) & 0x10) != 0)
685 if((s[rA] & 0x80) != 0)
688 case 0x37: s[rF] = s[rF] & ~(FLAGN | FLAGH) | FLAGC; return 4;
693 case 0x18: return branch(1, 0);
694 case 0x28: return branch((s[rF] & FLAGZ) != 0, 0);
695 case 0x38: return branch((s[rF] & FLAGC) != 0, 0);
696 case 0x09: return addhl(BC());
697 case 0x19: return addhl(DE());
698 case 0x29: return addhl(HL());
699 case 0x39: return addhl(sp);
700 case 0x0a: s[rA] = z80read(BC()); return 7;
701 case 0x1a: s[rA] = z80read(DE()); return 7;
702 case 0x2a: v = fetch16(); s[rL] = z80read(v++); s[rH] = z80read(v); return 16;
703 case 0x3a: s[rA] = z80read(fetch16()); return 13;
704 case 0x0b: if(s[rC]-- == 0) s[rB]--; return 6;
705 case 0x1b: if(s[rE]-- == 0) s[rD]--; return 6;
706 case 0x2b: if(s[rL]-- == 0) s[rH]--; return 6;
707 case 0x3b: sp--; return 6;
708 case 0x0c: inc(s[rC]++); return 4;
709 case 0x1c: inc(s[rE]++); return 4;
710 case 0x2c: inc(s[rL]++); return 4;
711 case 0x3c: inc(s[rA]++); return 4;
712 case 0x0d: dec(s[rC]--); return 4;
713 case 0x1d: dec(s[rE]--); return 4;
714 case 0x2d: dec(s[rL]--); return 4;
715 case 0x3d: dec(s[rA]--); return 4;
716 case 0x0e: s[rC] = fetch8(); return 7;
717 case 0x1e: s[rE] = fetch8(); return 7;
718 case 0x2e: s[rL] = fetch8(); return 7;
719 case 0x3e: s[rA] = fetch8(); return 7;
721 s[rF] = s[rF] & ~(FLAGC|FLAGN|FLAGH) | s[rA] & 1;
722 s[rA] = s[rA] >> 1 | s[rA] << 7;
726 s[rF] = s[rF] & ~(FLAGC|FLAGN|FLAGH) | s[rA] & 1;
727 s[rA] = s[rA] >> 1 | v;
730 s[rF] |= FLAGN|FLAGH;
734 s[rF] = s[rF] & ~(FLAGN|FLAGH) ^ FLAGC | s[rF] << 4 & FLAGH;
736 case 0xc0: if((s[rF] & FLAGZ) == 0) {spc = pop16(); return 11;} return 5;
737 case 0xd0: if((s[rF] & FLAGC) == 0) {spc = pop16(); return 11;} return 5;
738 case 0xe0: if((s[rF] & FLAGV) == 0) {spc = pop16(); return 11;} return 5;
739 case 0xf0: if((s[rF] & FLAGS) == 0) {spc = pop16(); return 11;} return 5;
740 case 0xc1: s[rC] = pop8(); s[rB] = pop8(); return 10;
741 case 0xd1: s[rE] = pop8(); s[rD] = pop8(); return 10;
742 case 0xe1: s[rL] = pop8(); s[rH] = pop8(); return 10;
743 case 0xf1: s[rF] = pop8(); s[rA] = pop8(); return 10;
744 case 0xc2: return jump((s[rF] & FLAGZ) == 0);
745 case 0xd2: return jump((s[rF] & FLAGC) == 0);
746 case 0xe2: return jump((s[rF] & FLAGV) == 0);
747 case 0xf2: return jump((s[rF] & FLAGS) == 0);
748 case 0xc3: return jump(1);
749 case 0xd3: z80out(fetch8(), s[rA]); return 11;
753 s[rH] = z80read(sp + 1);
756 case 0xf3: intm &= 0x3f; return 4;
757 case 0xc4: return call(fetch16(), (s[rF] & FLAGZ) == 0);
758 case 0xd4: return call(fetch16(), (s[rF] & FLAGC) == 0);
759 case 0xe4: return call(fetch16(), (s[rF] & FLAGV) == 0);
760 case 0xf4: return call(fetch16(), (s[rF] & FLAGS) == 0);
761 case 0xc5: push8(s[rB]); push8(s[rC]); return 11;
762 case 0xd5: push8(s[rD]); push8(s[rE]); return 11;
763 case 0xe5: push8(s[rH]); push8(s[rL]); return 11;
764 case 0xf5: push8(s[rA]); push8(s[rF]); return 11;
765 case 0xc6: return alu(0, 8);
766 case 0xd6: return alu(2, 8);
767 case 0xe6: return alu(4, 8);
768 case 0xf6: return alu(6, 8);
769 case 0xc7: return call(0x00, 1);
770 case 0xd7: return call(0x10, 1);
771 case 0xe7: return call(0x20, 1);
772 case 0xf7: return call(0x30, 1);
773 case 0xc8: if((s[rF] & FLAGZ) != 0) {spc = pop16(); return 11;} return 5;
774 case 0xd8: if((s[rF] & FLAGC) != 0) {spc = pop16(); return 11;} return 5;
775 case 0xe8: if((s[rF] & FLAGV) != 0) {spc = pop16(); return 11;} return 5;
776 case 0xf8: if((s[rF] & FLAGS) != 0) {spc = pop16(); return 11;} return 5;
777 case 0xc9: spc = pop16(); return 10;
786 case 0xe9: spc = HL(); return 4;
787 case 0xf9: sp = HL(); return 6;
788 case 0xca: return jump((s[rF] & FLAGZ) != 0);
789 case 0xda: return jump((s[rF] & FLAGC) != 0);
790 case 0xea: return jump((s[rF] & FLAGV) != 0);
791 case 0xfa: return jump((s[rF] & FLAGS) != 0);
792 case 0xcb: return bits(-1);
793 case 0xdb: s[rA] = z80in(fetch8()); return 11;
801 case 0xfb: intm |= 0xc0; return 4;
802 case 0xcc: return call(fetch16(), (s[rF] & FLAGZ) != 0);
803 case 0xdc: return call(fetch16(), (s[rF] & FLAGC) != 0);
804 case 0xec: return call(fetch16(), (s[rF] & FLAGV) != 0);
805 case 0xfc: return call(fetch16(), (s[rF] & FLAGS) != 0);
806 case 0xcd: return call(fetch16(), 1);
807 case 0xdd: return index(0);
808 case 0xed: return ed();
809 case 0xfd: return index(1);
810 case 0xce: return alu(1, 8);
811 case 0xde: return alu(3, 8);
812 case 0xee: return alu(5, 8);
813 case 0xfe: return alu(7, 8);
814 case 0xcf: return call(0x08, 1);
815 case 0xdf: return call(0x18, 1);
816 case 0xef: return call(0x28, 1);
817 case 0xff: return call(0x38, 1);
819 sysfatal("undefined z80 opcode %#.2x at pc=%#.4x", op, scurpc);