sdcc-extra/emu/rrz80/cpu/z80_step.c

   1 /*
   2  * Copyright (C) 1996-1998 Szeredi Miklos
   3  * Email: mszeredi@inf.bme.hu
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version. See the file COPYING.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  18  *
  19  */
  20
  21 #include "z80_def.h"
  22
  23 byte z80c_incf_tbl[256];
  24 byte z80c_decf_tbl[256];
  25 byte z80c_addf_tbl[256];
  26 byte z80c_subf_tbl[256];
  27 byte z80c_orf_tbl[256];
  28
  29 /* PENDING: Forward definitions. */
  30 void debug_z80(void);
  31 void profile_z80(int addr, int ticks);
  32
  33 void PRNM(pushpc)(void)
  34 {
  35 #ifdef PROCP
  36   Z80 *z80p;
  37   z80p = &PRNM(proc);
  38 #endif
  39
  40   SP--;
  41   PUTMEM(SP, SPP, PCH);
  42   SP--;
  43   PUTMEM(SP, SPP, PCL);
  44 }
  45
  46 static int parity(int b)
  47 {
  48   int i;
  49   int par;
  50
  51   par = 0;
  52   for(i = 8; i; i--) par ^= (b & 1), b >>= 1;
  53   return par;
  54 }
  55
  56 void PRNM(local_init)(void)
  57 {
  58   int i;
  59
  60 #ifdef PROCP
  61   Z80 *z80p;
  62   z80p = &PRNM(proc);
  63 #endif
  64
  65   for(i = 0; i < 0x100; i++) {
  66     z80c_incf_tbl[i] = z80c_decf_tbl[i] = z80c_orf_tbl[i] = 0;
  67
  68     z80c_orf_tbl[i] |= i & (SF | B3F | B5F);
  69     z80c_incf_tbl[i] |= i & (SF | B3F | B5F);
  70     z80c_decf_tbl[i] |= i & (SF | B3F | B5F);
  71
  72     if(!parity(i)) z80c_orf_tbl[i] |= PVF;
  73   }
  74
  75   z80c_incf_tbl[0] |= ZF;
  76   z80c_decf_tbl[0] |= ZF;
  77   z80c_orf_tbl[0] |= ZF;
  78
  79   z80c_incf_tbl[0x80] |= PVF;
  80   z80c_decf_tbl[0x7F] |= PVF;
  81
  82   for(i = 0; i < 0x100; i++) {
  83     int cr, c1, c2;
  84     int hr, h1, h2;
  85     int b5r;
  86
  87     cr  = i & 0x80;
  88     c1  = i & 0x40;
  89     b5r = i & 0x20;
  90     c2  = i & 0x10;
  91
  92     hr  = i & 0x08;
  93     h1  = i & 0x04;
  94     h2  = i & 0x01;
  95
  96     z80c_addf_tbl[i] = 0;
  97     z80c_subf_tbl[i] = 0;
  98     if(cr) {
  99       z80c_addf_tbl[i] |= SF;
 100       z80c_subf_tbl[i] |= SF;
 101     }
 102     if(b5r) {
 103       z80c_addf_tbl[i] |= B5F;
 104       z80c_subf_tbl[i] |= B5F;
 105     }
 106     if(hr) {
 107       z80c_addf_tbl[i] |= B3F;
 108       z80c_subf_tbl[i] |= B3F;
 109     }
 110
 111     if((c1 && c2) || (!cr && (c1 || c2))) z80c_addf_tbl[i] |= CF;
 112     if((h1 && h2) || (!hr && (h1 || h2))) z80c_addf_tbl[i] |= HF;
 113
 114     if((!c1 && !c2 && cr) || (c1 && c2 && !cr)) z80c_addf_tbl[i] |= PVF;
 115
 116
 117     if((c2 && cr) || (!c1 && (c2 || cr))) z80c_subf_tbl[i] |= CF;
 118     if((h2 && hr) || (!h1 && (h2 || hr))) z80c_subf_tbl[i] |= HF;
 119
 120     if((!c2 && !cr && c1) || (c2 && cr && !c1)) z80c_subf_tbl[i] |= PVF;
 121
 122
 123     z80c_subf_tbl[i] |= NF;
 124   }
 125
 126
 127 #ifdef PROCP
 128   TAB(incf_tbl) = z80c_incf_tbl;
 129   TAB(decf_tbl) = z80c_decf_tbl;
 130   TAB(addf_tbl) = z80c_addf_tbl;
 131   TAB(subf_tbl) = z80c_subf_tbl;
 132   TAB(orf_tbl) = z80c_orf_tbl;
 133
 134   PORT(inports) = PRNM(inports);
 135   PORT(outports) = PRNM(outports);
 136 #ifdef SPECT_MEM
 137   SPECP(fe_inport_high) = SPNM(fe_inport_high);
 138 #endif
 139 #endif
 140 }
 141
 142
 143 int PRNM(step)(int tc)
 144 {
 145 #ifdef PROCP
 146   Z80 *z80p;
 147   z80p = &PRNM(proc);
 148 #endif
 149
 150   DANM(tc) = tc;
 151   DANM(rl7) = RR & 0x80;
 152
 153   if(DANM(haltstate)) {
 154     register int nn;
 155     nn = (DANM(tc) - 1) / 4 + 1;
 156
 157     DANM(tc) -= 4 * nn;
 158     RR += nn;
 159   }
 160   else do {
 161     register int nextop;
 162
 163 #if !DISABLE_PROFILE
 164     int pc = PC;
 165     int startTC = DANM(tc);
 166 #endif
 167
 168 #ifdef DEBUG_Z80
 169     debug_z80();
 170 #endif
 171     nextop = *PCP;
 172     PC++;
 173
 174 #ifdef PROCP
 175     z80p = (*z80c_op_tab[nextop])(z80p);
 176 #else
 177     (*z80c_op_tab[nextop])();
 178 #endif
 179
 180 #if !DISABLE_PROFILE
 181     profile_z80(pc, startTC - DANM(tc));
 182 #endif
 183
 184     RR++;
 185   } while(DANM(tc) > 0);
 186
 187   RR = (RR & 0x7F) | DANM(rl7);
 188   return DANM(tc);
 189 }