diff options
| -rw-r--r-- | z80_decode.c | 103 |
1 files changed, 31 insertions, 72 deletions
diff --git a/z80_decode.c b/z80_decode.c index 036e34e..74a8c1f 100644 --- a/z80_decode.c +++ b/z80_decode.c @@ -4,8 +4,8 @@ Copyright (C) 2006 Ian Cowburn <ianc@noddybox.co.uk> - Some of the opcode routines are based on the Z80 emulation from YAZE, - Copyright (c) 1995 Frank D. Cringle. + Some of the opcode routines are based on the Z80 emulation from FUSE, + Copyright (c) 1999-2003 Philip Kendall This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by @@ -36,25 +36,6 @@ static const char ident[]="$Id$"; /* ---------------------------------------- TABLES AND INIT */ -static const unsigned char partab[256] = { - 4,0,0,4,0,4,4,0,0,4,4,0,4,0,0,4, - 0,4,4,0,4,0,0,4,4,0,0,4,0,4,4,0, - 0,4,4,0,4,0,0,4,4,0,0,4,0,4,4,0, - 4,0,0,4,0,4,4,0,0,4,4,0,4,0,0,4, - 0,4,4,0,4,0,0,4,4,0,0,4,0,4,4,0, - 4,0,0,4,0,4,4,0,0,4,4,0,4,0,0,4, - 4,0,0,4,0,4,4,0,0,4,4,0,4,0,0,4, - 0,4,4,0,4,0,0,4,4,0,0,4,0,4,4,0, - 0,4,4,0,4,0,0,4,4,0,0,4,0,4,4,0, - 4,0,0,4,0,4,4,0,0,4,4,0,4,0,0,4, - 4,0,0,4,0,4,4,0,0,4,4,0,4,0,0,4, - 0,4,4,0,4,0,0,4,4,0,0,4,0,4,4,0, - 4,0,0,4,0,4,4,0,0,4,4,0,4,0,0,4, - 0,4,4,0,4,0,0,4,4,0,0,4,0,4,4,0, - 0,4,4,0,4,0,0,4,4,0,0,4,0,4,4,0, - 4,0,0,4,0,4,4,0,0,4,4,0,4,0,0,4, -}; - static Z80Byte PSZtable[512]; static Z80Byte SZtable[512]; static Z80Byte Ptable[512]; @@ -436,14 +417,14 @@ do { \ cpu->AF.b[LO]=CARRY|H_Z80; \ if ((REG)&(1<<B)) \ { \ - cpu->AF.b[LO]|=Z_Z80; \ - cpu->AF.b[LO]|=P_Z80; \ + if (B==7 && (REG&S_Z80)) cpu->AF.b[LO]|=S_Z80; \ + if (B==5 && (REG&B5_Z80)) cpu->AF.b[LO]|=B5_Z80; \ + if (B==3 && (REG&B3_Z80)) cpu->AF.b[LO]|=B3_Z80; \ } \ else \ { \ - if (B==7) cpu->AF.b[LO]|=S_Z80; \ - else if (B==5) cpu->AF.b[LO]|=B5_Z80; \ - else if (B==3) cpu->AF.b[LO]|=B3_Z80; \ + cpu->AF.b[LO]|=Z_Z80; \ + cpu->AF.b[LO]|=P_Z80; \ } \ } while(0) @@ -967,58 +948,31 @@ do { \ /* ---------------------------------------- DAA */ -/* This code based on the DAA opcode from YAZE, (c) Frank D. Cringle +/* This code based on the DAA opcode from FUSE, (c) Philip Kendall */ static void DAA (Z80 *cpu) { - Z80Word AF,acu,temp,cbits; + Z80Byte add=0; + Z80Byte carry=CARRY; - AF=cpu->AF.w; - acu=cpu->AF.b[HI]; - temp=acu&0xf; - cbits=CARRY; + if ((IS_H) || ((cpu->AF.b[HI] & 0x0f)>9)) add=6; - if (IS_N) /* last operation was a subtract */ - { - int hd = cbits || acu > 0x99; - if (IS_H || (temp > 9)) /* adjust low digit */ - { - if (temp > 5) - { - CLR(AF,H_Z80); - } + if (carry || (cpu->AF.b[HI] > 0x9f)) add|=0x60; - acu -= 6; - acu &= 0xff; - } - if (hd) /* adjust high digit */ - acu -= 0x160; + if (cpu->AF.b[HI] > 0x99 ) carry=1; + + if (IS_N) + { + SUB8(add); } - else /* last operation was an add */ + else { - if (IS_H || (temp > 9)) /* adjust low digit */ - { - if (temp>9) - { - SET(AF,H_Z80); - } - else - { - CLR(AF,H_Z80); - } - acu += 6; - } - if (cbits || ((acu & 0x1f0) > 0x90)) /* adjust high digit */ - acu += 0x60; + if ((cpu->AF.b[HI]>0x90) && ((cpu->AF.b[HI] & 0x0f)>9)) add|=0x60; + ADD8(add); } - cbits |= (acu >> 8) & 1; - acu &= 0xff; - AF = (acu << 8) | (acu & 0xa8) | ((acu == 0) << 6) | - (AF & 0x12) | partab[acu] | cbits; - - cpu->AF.w=AF; - SETHIDDEN(cpu->AF.b[HI]); + cpu->AF.b[LO] = (cpu->AF.b[LO] & ~(C_Z80|P_Z80)) + | carry | Ptable[cpu->AF.b[HI]]; } @@ -2034,9 +1988,12 @@ void Z80_Decode(Z80 *cpu, Z80Byte opcode) *L=FETCH_BYTE; break; - case 0x2f: /* RRA */ + case 0x2f: /* CPL */ TSTATE(4); - RRA; + cpu->AF.b[HI]^=0xff; + SETFLAG(H_Z80); + SETFLAG(N_Z80); + SETHIDDEN(cpu->AF.b[HI]); break; case 0x30: /* JR NC,d */ @@ -2078,8 +2035,9 @@ void Z80_Decode(Z80 *cpu, Z80Byte opcode) case 0x37: /* SCF */ TSTATE(4); - CLRFLAG(H_Z80); - SETFLAG(C_Z80); + cpu->AF.b[LO]=(cpu->AF.b[LO]&(S_Z80|Z_Z80|P_Z80)) + | C_Z80 + | (cpu->AF.b[HI]&(B3_Z80|B5_Z80)); break; case 0x38: /* JR C,d */ @@ -2125,6 +2083,7 @@ void Z80_Decode(Z80 *cpu, Z80Byte opcode) CLRFLAG(H_Z80); cpu->AF.b[LO]^=C_Z80; + SETHIDDEN(cpu->AF.b[HI]); break; LD_BLOCK(0x40,cpu->BC.b[HI],cpu->BC.b[HI]) |