Magazyn Amiga 5/MA_Cover_5.iso/ppc/atari/atari800-0.8.6/cpu_asm.c

C/C++ Source or Header | 1998-05-10 | 4.6 KB | 209 lines

#include    <stdio.h>
#include    <stdlib.h>
#include    <osbind.h>

static char *rcsid = "$Id: cpu_asm.c,v 1.2 1998/02/21 15:02:46 david Exp $";

#define    FALSE    0
#define    TRUE    1

#include    "atari.h"
#include    "cpu_asm.h"

long CEKEJ;
extern UBYTE IRQ;

extern UWORD break_addr;

/*
   ==========================================================
   Emulated Registers and Flags are kept local to this module
   ==========================================================
 */

#define    GetByte(addr)        ((attrib[addr] == HARDWARE) ? Atari800_GetByte(addr) : memory[addr])
#define    PutByte(addr,byte)    if (attrib[addr] == RAM) memory[addr] = byte; else if (attrib[addr] == HARDWARE) if (Atari800_PutByte(addr,byte)) break;


#define RAM 0
#define ROM 1
#define HARDWARE 2
int count[256];

extern void tisk(void);
UBYTE memory[65536];

UBYTE attrib[65536];

/*
   ===============================================================
   Z flag: This actually contains the result of an operation which
   would modify the Z flag. The value is tested for
   equality by the BEQ and BNE instruction.
   ===============================================================
 */



UBYTE BCDtoDEC[256];
UBYTE DECtoBCD[256];

void CPU_Reset(void)
{
    int i;

    for (i = 0; i < 256; i++) {
        BCDtoDEC[i] = ((i >> 4) & 0xf) * 10 + (i & 0xf);
        DECtoBCD[i] = (((i % 100) / 10) << 4) | (i % 10);
#ifdef PROFILE
        count[i] = 0;
#endif
    }

    IRQ = 0x00;

    regP = 0x20;                /* The unused bit is always 1 */
    regS = 0xff;
    regPC = (GetByte(0xfffd) << 8) | GetByte(0xfffc);
}

 /*  it was there only for debug purposes.....
    #define PHP data =  (N & 0x80); \
    data |= V ? 0x40 : 0; \
    data |= (regP & 0x3c); \
    data |= (Z == 0) ? 0x02 : 0; \
    data |= C; \
    memory[0x0100 + S--] = data;

    void NMI (void)
    {
    UBYTE S = regS;
    UBYTE data;

    memory[0x0100 + S--] = regPC >> 8;
    memory[0x0100 + S--] = regPC & 0xff;
    memory[0x100 + S--] = regP;
    SetI;
    regPC = (memory[0xfffb] << 8) | memory[0xfffa];
    regS = S;
    }
  */

void SetRAM(int addr1, int addr2)
{
    int i;

    for (i = addr1; i <= addr2; i++) {
        attrib[i] = RAM;
    }
}

void SetROM(int addr1, int addr2)
{
    int i;

    for (i = addr1; i <= addr2; i++) {
        attrib[i] = ROM;
    }
}

void SetHARDWARE(int addr1, int addr2)
{
    int i;

    for (i = addr1; i <= addr2; i++) {
        attrib[i] = HARDWARE;
    }
}

UBYTE GETBYTE(UWORD addr)
{
    UBYTE byte;
/*
   ============================================================
   GTIA, POKEY, PIA and ANTIC do not fully decode their address
   ------------------------------------------------------------
   PIA (At least) is fully decoded when emulating the XL/XE
   ============================================================
 */
    switch (addr & 0xff00) {
    case 0xd000:                /* GTIA */
        byte = GTIA_GetByte(addr - 0xd000);
        break;
    case 0xd200:                /* POKEY */
        byte = POKEY_GetByte(addr - 0xd200);
        break;
    case 0xd300:                /* PIA */
        byte = PIA_GetByte(addr - 0xd300);
        break;
    case 0xd400:                /* ANTIC */
        byte = ANTIC_GetByte(addr - 0xd400);
        break;
    case 0xc000:                /* GTIA - 5200 */
        byte = GTIA_GetByte(addr - 0xc000);
        break;
    case 0xe800:                /* POKEY - 5200 */
        byte = POKEY_GetByte(addr - 0xe800);
        break;
    case 0xeb00:                /* POKEY - 5200 */
        byte = POKEY_GetByte(addr - 0xeb00);
        break;
    default:
        break;
    }

    return byte;
}

int PUTBYTE(UWORD addr, UBYTE byte)
{
    int abort = TRUE;            /*FALSE; */
/*
   ============================================================
   GTIA, POKEY, PIA and ANTIC do not fully decode their address
   ------------------------------------------------------------
   PIA (At least) is fully decoded when emulating the XL/XE
   ============================================================
 */
    switch (addr & 0xff00) {
    case 0xd000:                /* GTIA */
        abort = GTIA_PutByte(addr - 0xd000, byte);
        break;
    case 0xd200:                /* POKEY */
        abort = POKEY_PutByte(addr - 0xd200, byte);
        break;
    case 0xd300:                /* PIA */
        abort = PIA_PutByte(addr - 0xd300, byte);
        break;
    case 0xd400:                /* ANTIC */
        abort = ANTIC_PutByte(addr - 0xd400, byte);
        break;
    case 0xd500:                /* Super Cartridges */
        abort = SuperCart_PutByte(addr, byte);
        break;
    case 0xc000:                /* GTIA - 5200 */
        abort = GTIA_PutByte(addr - 0xc000, byte);
        break;
    case 0xeb00:                /* POKEY - 5200 */
        abort = POKEY_PutByte(addr - 0xeb00, byte);
        break;
    default:
        break;
    }

    return abort;
}

void CPU_GetStatus(void)
{
    CPUGET();
}

void tisk(void)
{
    void *adresa = (long *) 0x400000;
    printf("OLD %d %d %d %d %d %d\n", *(UBYTE *) (adresa - 1), *(UBYTE *) (adresa - 2),
           *(UBYTE *) (adresa - 3), *(UBYTE *) (adresa - 4), *(UBYTE *) (adresa - 5), *(UWORD *) (adresa - 8));
    printf("NEW %d %d %d %d %d %d\n", regP, regS, regA, regX, regY, regPC);
}