sdcc-extra/emu/rrz80/cpu/z80.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.h"
  22
  23 #include <stdio.h>
  24 #include <stdlib.h>
  25 #include <string.h>
  26 #include <time.h>
  27
  28 Z80 PRNM(proc);
  29
  30 byte PRNM(inports)[PORTNUM];
  31 byte PRNM(outports)[PORTNUM];
  32
  33
  34 #ifdef SPECT_MEM
  35 #define NUM64KSEGS 3
  36 #endif
  37
  38 #ifndef NUM64KSEGS
  39 #define NUM64KSEGS 1
  40 #endif
  41
  42 static byte *a64kmalloc(int num64ksegs)
  43 {
  44   byte *bigmem;
  45
  46   bigmem = (byte *) malloc((unsigned) (0x10000 * (num64ksegs + 1)));
  47   if(bigmem == NULL) {
  48     fprintf(stderr, "Out of memory!\n");
  49     exit(1);
  50   }
  51
  52   return (byte *) (( (long) bigmem & ~((long) 0xFFFF)) + 0x10000);
  53 }
  54
  55
  56
  57 void PRNM(init)(void)
  58 {
  59   qbyte i;
  60
  61   DANM(mem) = a64kmalloc(NUM64KSEGS);
  62
  63   srand((unsigned int) time(NULL));
  64 #if RAND_FILL_MEM
  65   for(i = 0; i < 0x10000; i++) DANM(mem)[i] = (byte) rand();
  66 #elif CLEAR_MEM
  67   memset(DANM(mem), 0, 0x10000);
  68 #endif
  69
  70   for(i = 0; i < NUMDREGS; i++) {
  71     DANM(nr)[i].p = DANM(mem);
  72     DANM(nr)[i].d.d = (dbyte) rand();
  73   }
  74
  75   for(i = 0; i < BACKDREGS; i++) {
  76     DANM(br)[i].p = DANM(mem);
  77     DANM(br)[i].d.d = (dbyte) rand();
  78   }
  79
  80   for(i = 0; i < PORTNUM; i++) PRNM(inports)[i] = PRNM(outports)[i] = 0;
  81
  82   PRNM(local_init)();
  83
  84   return;
  85 }
  86
  87 /* TODO: no interrupt immediately afer EI (not important for spectrum) */
  88
  89 void PRNM(nmi)(void)
  90 {
  91   DANM(iff2) = DANM(iff1);
  92   DANM(iff1) = 0;
  93
  94   DANM(haltstate) = 0;
  95   PRNM(pushpc)();
  96
  97   PC = 0x0066;
  98 }
  99
 100 /* TODO: IM 0 emulation */
 101
 102 void PRNM(interrupt)(int data)
 103 {
 104   if(DANM(iff1)) {
 105
 106     DANM(haltstate) = 0;
 107     DANM(iff1) = DANM(iff2) = 0;
 108
 109     switch(DANM(it_mode)) {
 110     case 0:
 111       PRNM(pushpc)();
 112       PC = 0x0038;
 113       break;
 114     case 1:
 115       PRNM(pushpc)();
 116       PC = 0x0038;
 117       break;
 118     case 2:
 119       PRNM(pushpc)();
 120       PCL = DANM(mem)[(dbyte) (((int) RI << 8) + (data & 0xFF))];
 121       PCH = DANM(mem)[(dbyte) (((int) RI << 8) + (data & 0xFF) + 1)];
 122       break;
 123     }
 124   }
 125 }
 126
 127
 128 void PRNM(reset)(void)
 129 {
 130   DANM(haltstate) = 0;
 131   DANM(iff1) = DANM(iff2) = 0;
 132   DANM(it_mode) = 0;
 133   RI = 0;
 134   RR = 0;
 135   PC = 0;
 136 }