apps/plugins/zxbox/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 <time.h>
  26 #include "zxconfig.h"
  27 #include "helpers.h"
  28 Z80 PRNM(proc) IBSS_ATTR;
  29
  30 byte PRNM(inports)[PORTNUM] IBSS_ATTR;
  31 byte PRNM(outports)[PORTNUM] IBSS_ATTR;
  32
  33 #ifdef SPECT_MEM
  34 #define NUM64KSEGS 3
  35 #endif
  36
  37 #ifndef NUM64KSEGS
  38 #define NUM64KSEGS 1
  39 #endif
  40
  41 static byte *a64kmalloc(int num64ksegs)
  42 {
  43   byte *bigmem;
  44
  45   bigmem = (byte *) my_malloc((unsigned) (0x10000 * (num64ksegs + 1)));
  46   if(bigmem == NULL) {
  47     /*fprintf(stderr, "Out of memory!\n");*/
  48     /*exit(1);*/
  49   }
  50
  51   return (byte *) (( (long) bigmem & ~((long) 0xFFFF)) + 0x10000);
  52 }
  53
  54
  55
  56 void PRNM(init)(void)
  57 {
  58   qbyte i;
  59
  60   DANM(mem) = a64kmalloc(NUM64KSEGS);
  61
  62   rb->srand((unsigned int)( rb->get_time()->tm_sec+rb->get_time()->tm_min*60 + rb->get_time()->tm_hour*3600));
  63   for(i = 0; i < 0x10000; i++) DANM(mem)[i] = (byte) rb->rand();
  64
  65   for(i = 0; i < NUMDREGS; i++) {
  66     DANM(nr)[i].p = DANM(mem);
  67     DANM(nr)[i].d.d = (dbyte) rb->rand();
  68   }
  69
  70   for(i = 0; i < BACKDREGS; i++) {
  71     DANM(br)[i].p = DANM(mem);
  72     DANM(br)[i].d.d = (dbyte) rb->rand();
  73   }
  74
  75   for(i = 0; i < PORTNUM; i++) PRNM(inports)[i] = PRNM(outports)[i] = 0;
  76
  77   PRNM(local_init)();
  78
  79   return;
  80 }
  81
  82 /* TODO: no interrupt immediately afer EI (not important for spectrum) */
  83
  84 void PRNM(nmi)(void)
  85 {
  86   DANM(iff2) = DANM(iff1);
  87   DANM(iff1) = 0;
  88
  89   DANM(haltstate) = 0;
  90   PRNM(pushpc)();
  91
  92   PC = 0x0066;
  93 }
  94
  95 /* TODO: IM 0 emulation */
  96
  97 void PRNM(interrupt)(int data)
  98 {
  99   if(DANM(iff1)) {
 100
 101     DANM(haltstate) = 0;
 102     DANM(iff1) = DANM(iff2) = 0;
 103
 104     switch(DANM(it_mode)) {
 105     case 0:
 106       PRNM(pushpc)();
 107       PC = 0x0038;
 108       break;
 109     case 1:
 110       PRNM(pushpc)();
 111       PC = 0x0038;
 112       break;
 113     case 2:
 114       PRNM(pushpc)();
 115       PCL = DANM(mem)[(dbyte) (((int) RI << 8) + (data & 0xFF))];
 116       PCH = DANM(mem)[(dbyte) (((int) RI << 8) + (data & 0xFF) + 1)];
 117       break;
 118     }
 119   }
 120 }
 121
 122
 123 void PRNM(reset)(void)
 124 {
 125   DANM(haltstate) = 0;
 126   DANM(iff1) = DANM(iff2) = 0;
 127   DANM(it_mode) = 0;
 128   RI = 0;
 129   RR = 0;
 130   PC = 0;
 131 }