📄 m6809.c
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Regs->pending_interrupts = pending_interrupts; /* NS 970908 */
}
/****************************************************************************/
/* Return program counter */
/****************************************************************************/
unsigned m6809_GetPC(void)
{
return pcreg;
}
/* Generate interrupts */
INLINE void Interrupt(void) /* NS 970909 */
{
if ((pending_interrupts & M6809_INT_NMI) != 0)
{
pending_interrupts &= ~M6809_INT_NMI;
/* NMI */
cc|=0x80; /* ASG 971016 */
PUSHWORD(pcreg);
PUSHWORD(ureg);
PUSHWORD(yreg);
PUSHWORD(xreg);
PUSHBYTE(dpreg);
PUSHBYTE(breg);
PUSHBYTE(areg);
PUSHBYTE(cc);
cc|=0xd0;
pcreg=M_RDMEM_WORD(0xfffc);change_pc(pcreg); /* TS 971002 */
m6809_ICount -= 19;
}
else if ((pending_interrupts & M6809_INT_IRQ) != 0 && (cc & 0x10) == 0)
{
pending_interrupts &= ~M6809_INT_IRQ;
/* standard IRQ */
cc|=0x80; /* ASG 971016 */
PUSHWORD(pcreg);
PUSHWORD(ureg);
PUSHWORD(yreg);
PUSHWORD(xreg);
PUSHBYTE(dpreg);
PUSHBYTE(breg);
PUSHBYTE(areg);
PUSHBYTE(cc);
cc|=0x90;
pcreg=M_RDMEM_WORD(0xfff8);change_pc(pcreg); /* TS 971002 */
m6809_ICount -= 19;
}
else if ((pending_interrupts & M6809_INT_FIRQ) != 0 && (cc & 0x40) == 0)
{
pending_interrupts &= ~M6809_INT_FIRQ;
/* fast IRQ */
PUSHWORD(pcreg);
cc&=0x7f; /* ASG 971016 */
PUSHBYTE(cc);
cc|=0x50;
pcreg=M_RDMEM_WORD(0xfff6);change_pc(pcreg); /* TS 971002 */
m6809_ICount -= 10;
}
}
void m6809_reset(void)
{
pcreg = M_RDMEM_WORD(0xfffe);change_pc(pcreg); /* TS 971002 */
dpreg = 0x00; /* Direct page register = 0x00 */
cc = 0x00; /* Clear all flags */
cc |= 0x10; /* IRQ disabled */
cc |= 0x40; /* FIRQ disabled */
areg = 0x00; /* clear accumulator a */
breg = 0x00; /* clear accumulator b */
m6809_Clear_Pending_Interrupts(); /* NS 970908 */
/* default to unoptimized memory access */
rd_u_handler = rd_slow;
rd_u_handler_wd = rd_slow_wd;
rd_s_handler = rd_slow;
rd_s_handler_wd = rd_slow_wd;
wr_u_handler = wr_slow;
wr_u_handler_wd = wr_slow_wd;
wr_s_handler = wr_slow;
wr_s_handler_wd = wr_slow_wd;
/* optimize memory access according to flags */
if( m6809_Flags & M6809_FAST_U )
{
rd_u_handler=rd_fast; rd_u_handler_wd=rd_fast_wd;
wr_u_handler=wr_fast; wr_u_handler_wd=wr_fast_wd;
}
if( m6809_Flags & M6809_FAST_S )
{
rd_s_handler=rd_fast; rd_s_handler_wd=rd_fast_wd;
wr_s_handler=wr_fast; wr_s_handler_wd=wr_fast_wd;
}
}
void m6809_Cause_Interrupt(int type) /* NS 970908 */
{
pending_interrupts |= type;
if (type & (M6809_INT_NMI | M6809_INT_IRQ | M6809_INT_FIRQ))
{
pending_interrupts &= ~M6809_SYNC;
if (pending_interrupts & M6809_CWAI)
{
if ((pending_interrupts & M6809_INT_NMI) != 0)
pending_interrupts &= ~M6809_CWAI;
else if ((pending_interrupts & M6809_INT_IRQ) != 0 && (cc & 0x10) == 0)
pending_interrupts &= ~M6809_CWAI;
else if ((pending_interrupts & M6809_INT_FIRQ) != 0 && (cc & 0x40) == 0)
pending_interrupts &= ~M6809_CWAI;
}
}
}
void m6809_Clear_Pending_Interrupts(void) /* NS 970908 */
{
pending_interrupts &= ~(M6809_INT_IRQ | M6809_INT_FIRQ | M6809_INT_NMI);
}
#include "6809ops.c"
/* execute instructions on this CPU until icount expires */
int m6809_execute(int cycles) /* NS 970908 */
{
byte op_count; /* op code clock count */
byte ireg;
m6809_ICount = cycles; /* NS 970908 */
if (pending_interrupts & (M6809_CWAI | M6809_SYNC))
{
m6809_ICount = 0;
goto getout;
}
do
{
extern int previouspc;
previouspc = pcreg;
if (pending_interrupts != 0)
Interrupt(); /* NS 970908 */
ireg=M_RDOP(pcreg++);
if( (op_count = cycles1[ireg])!=0xff ){
if( op_count &0x80 ) op_count += fetch_effective_address();
switch( ireg )
{
case 0x00: neg_di(); break;
case 0x03: com_di(); break;
case 0x04: lsr_di(); break;
case 0x06: ror_di(); break;
case 0x07: asr_di(); break;
case 0x08: asl_di(); break;
case 0x09: rol_di(); break;
case 0x0a: dec_di(); break;
case 0x0c: inc_di(); break;
case 0x0d: tst_di(); break;
case 0x0e: jmp_di(); if (m6809_slapstic) cpu_setOPbase16(pcreg); break;
case 0x0f: clr_di(); break;
case 0x12: nop(); break;
case 0x13: sync6809(); break;
case 0x16: lbra(); break;
case 0x17: lbsr(); break;
case 0x19: daa(); break;
case 0x1a: orcc(); break;
case 0x1c: andcc(); break;
case 0x1d: sex(); break;
case 0x1e: exg(); break;
case 0x1f: tfr(); break;
case 0x20: bra(); break;
case 0x21: brn(); break;
case 0x22: bhi(); break;
case 0x23: bls(); break;
case 0x24: bcc(); break;
case 0x25: bcs(); break;
case 0x26: bne(); break;
case 0x27: beq(); break;
case 0x28: bvc(); break;
case 0x29: bvs(); break;
case 0x2a: bpl(); break;
case 0x2b: bmi(); break;
case 0x2c: bge(); break;
case 0x2d: blt(); break;
case 0x2e: bgt(); break;
case 0x2f: ble(); break;
case 0x30: leax(); break;
case 0x31: leay(); break;
case 0x32: leas(); break;
case 0x33: leau(); break;
case 0x34: pshs(); break;
case 0x35: puls(); break;
case 0x36: pshu(); break;
case 0x37: pulu(); break;
case 0x39: rts(); break;
case 0x3a: abx(); break;
case 0x3b: rti(); break;
case 0x3c: cwai(); break;
case 0x3d: mul(); break;
case 0x3f: swi(); break;
case 0x40: nega(); break;
case 0x43: coma(); break;
case 0x44: lsra(); break;
case 0x46: rora(); break;
case 0x47: asra(); break;
case 0x48: asla(); break;
case 0x49: rola(); break;
case 0x4a: deca(); break;
case 0x4c: inca(); break;
case 0x4d: tsta(); break;
case 0x4f: clra(); break;
case 0x50: negb(); break;
case 0x53: comb(); break;
case 0x54: lsrb(); break;
case 0x56: rorb(); break;
case 0x57: asrb(); break;
case 0x58: aslb(); break;
case 0x59: rolb(); break;
case 0x5a: decb(); break;
case 0x5c: incb(); break;
case 0x5d: tstb(); break;
case 0x5f: clrb(); break;
case 0x60: neg_ix(); break;
case 0x63: com_ix(); break;
case 0x64: lsr_ix(); break;
case 0x66: ror_ix(); break;
case 0x67: asr_ix(); break;
case 0x68: asl_ix(); break;
case 0x69: rol_ix(); break;
case 0x6a: dec_ix(); break;
case 0x6c: inc_ix(); break;
case 0x6d: tst_ix(); break;
case 0x6e: jmp_ix(); if (m6809_slapstic) cpu_setOPbase16(pcreg); break;
case 0x6f: clr_ix(); break;
case 0x70: neg_ex(); break;
case 0x73: com_ex(); break;
case 0x74: lsr_ex(); break;
case 0x76: ror_ex(); break;
case 0x77: asr_ex(); break;
case 0x78: asl_ex(); break;
case 0x79: rol_ex(); break;
case 0x7a: dec_ex(); break;
case 0x7c: inc_ex(); break;
case 0x7d: tst_ex(); break;
case 0x7e: jmp_ex(); if (m6809_slapstic) cpu_setOPbase16(pcreg); break;
case 0x7f: clr_ex(); break;
case 0x80: suba_im(); break;
case 0x81: cmpa_im(); break;
case 0x82: sbca_im(); break;
case 0x83: subd_im(); break;
case 0x84: anda_im(); break;
case 0x85: bita_im(); break;
case 0x86: lda_im(); break;
case 0x87: sta_im(); break; /* ILLEGAL? */
case 0x88: eora_im(); break;
case 0x89: adca_im(); break;
case 0x8a: ora_im(); break;
case 0x8b: adda_im(); break;
case 0x8c: cmpx_im(); break;
case 0x8d: bsr(); break;
case 0x8e: ldx_im(); break;
case 0x8f: stx_im(); break; /* ILLEGAL? */
case 0x90: suba_di(); break;
case 0x91: cmpa_di(); break;
case 0x92: sbca_di(); break;
case 0x93: subd_di(); break;
case 0x94: anda_di(); break;
case 0x95: bita_di(); break;
case 0x96: lda_di(); break;
case 0x97: sta_di(); break;
case 0x98: eora_di(); break;
case 0x99: adca_di(); break;
case 0x9a: ora_di(); break;
case 0x9b: adda_di(); break;
case 0x9c: cmpx_di(); break;
case 0x9d: jsr_di(); if (m6809_slapstic) cpu_setOPbase16(pcreg); break;
case 0x9e: ldx_di(); break;
case 0x9f: stx_di(); break;
case 0xa0: suba_ix(); break;
case 0xa1: cmpa_ix(); break;
case 0xa2: sbca_ix(); break;
case 0xa3: subd_ix(); break;
case 0xa4: anda_ix(); break;
case 0xa5: bita_ix(); break;
case 0xa6: lda_ix(); break;
case 0xa7: sta_ix(); break;
case 0xa8: eora_ix(); break;
case 0xa9: adca_ix(); break;
case 0xaa: ora_ix(); break;
case 0xab: adda_ix(); break;
case 0xac: cmpx_ix(); break;
case 0xad: jsr_ix(); if (m6809_slapstic) cpu_setOPbase16(pcreg); break;
case 0xae: ldx_ix(); break;
case 0xaf: stx_ix(); break;
case 0xb0: suba_ex(); break;
case 0xb1: cmpa_ex(); break;
case 0xb2: sbca_ex(); break;
case 0xb3: subd_ex(); break;
case 0xb4: anda_ex(); break;
case 0xb5: bita_ex(); break;
case 0xb6: lda_ex(); break;
case 0xb7: sta_ex(); break;
case 0xb8: eora_ex(); break;
case 0xb9: adca_ex(); break;
case 0xba: ora_ex(); break;
case 0xbb: adda_ex(); break;
case 0xbc: cmpx_ex(); break;
case 0xbd: jsr_ex(); if (m6809_slapstic) cpu_setOPbase16(pcreg); break;
case 0xbe: ldx_ex(); break;
case 0xbf: stx_ex(); break;
case 0xc0: subb_im(); break;
case 0xc1: cmpb_im(); break;
case 0xc2: sbcb_im(); break;
case 0xc3: addd_im(); break;
case 0xc4: andb_im(); break;
case 0xc5: bitb_im(); break;
case 0xc6: ldb_im(); break;
case 0xc7: stb_im(); break; /* ILLEGAL? */
case 0xc8: eorb_im(); break;
case 0xc9: adcb_im(); break;
case 0xca: orb_im(); break;
case 0xcb: addb_im(); break;
case 0xcc: ldd_im(); break;
case 0xcd: std_im(); break; /* ILLEGAL? */
case 0xce: ldu_im(); break;
case 0xcf: stu_im(); break; /* ILLEGAL? */
case 0xd0: subb_di(); break;
case 0xd1: cmpb_di(); break;
case 0xd2: sbcb_di(); break;
case 0xd3: addd_di(); break;
case 0xd4: andb_di(); break;
case 0xd5: bitb_di(); break;
case 0xd6: ldb_di(); break;
case 0xd7: stb_di(); break;
case 0xd8: eorb_di(); break;
case 0xd9: adcb_di(); break;
case 0xda: orb_di(); break;
case 0xdb: addb_di(); break;
case 0xdc: ldd_di(); break;
case 0xdd: std_di(); break;
case 0xde: ldu_di(); break;
case 0xdf: stu_di(); break;
case 0xe0: subb_ix(); break;
case 0xe1: cmpb_ix(); break;
case 0xe2: sbcb_ix(); break;
case 0xe3: addd_ix(); break;
case 0xe4: andb_ix(); break;
case 0xe5: bitb_ix(); break;
case 0xe6: ldb_ix(); break;
case 0xe7: stb_ix(); break;
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