Esempio n. 1
0
static char * TXA1() {
    CPU *c = getCPU();
    OP_CODE_INFO *o = getOP_CODE_INFO(0,0,modeImmediate);
    setRegByte(c,IND_X,-50);
    setRegByte(c,ACCUM,39);
    txa(c,o);
    int8_t accumVal = getRegByte(c,ACCUM);
    mu_assert("TXA1 err, ACCUM reg != -50", accumVal == -50);
    mu_run_test_with_args(testRegStatus,c,"10100000",
            "          NVUBDIZC    NVUBDIZC\nTXA1 err, %s != %s");
    freeOP_CODE_INFO(o);
    free(c);
    return 0;
}
Esempio n. 2
0
File: main.c Progetto: ornata/6502
// run appropriate function for opcode in memory
void execute_cpu(machine* mch)
{
	uint8_t *opcode = &mch->memory[mch->pc++];
	uint8_t *memory = mch->memory;

	fprintf(stdout, "opcode: %x\n", opcode[0]);

	switch(*opcode) {
		case 0x02: exit(123);
		case 0x12: exit(123);
		case 0x22: exit(123);
		case 0x32: exit(123);
		case 0x42: exit(123);
		case 0x52: exit(123);
		case 0x62: exit(123);
		case 0x72: exit(123);
		case 0x92: exit(123);
		case 0xB2: exit(123);
		case 0xD2: exit(123);
		case 0xF2: exit(123);
		case 0xEA: return nop(mch, 1);
		case 0x1A: return nop(mch, 2); // illegal instruction (nop with 2 cycles)
		case 0x7A: return nop(mch, 2); // same as above
		case 0x69: return adc_imm(opcode[1], mch);
		case 0x65: return adc_zp(opcode[1], mch);
		case 0x75: return adc_zpx(opcode[1], mch);
		case 0x6D: return adc_abs(opcode[2], opcode[1], mch);
		case 0x7D: return adc_absx(opcode[2], opcode[1], mch);
		case 0x79: return adc_absy(opcode[2], opcode[1], mch);
		case 0x61: return adc_indx(opcode[2], opcode[1], mch);
		case 0x71: return adc_indy(opcode[2], opcode[1], mch);
		case 0x29: return and_imm(opcode[1], mch);
		case 0x25: return and_zp(opcode[1], mch);
		case 0x35: return and_zpx(opcode[1], mch);
		case 0x2D: return and_abs(opcode[2], opcode[1], mch);
		case 0x3D: return and_absx(opcode[2], opcode[1], mch);
		case 0x39: return and_absy(opcode[2], opcode[1], mch);
		case 0x21: return and_indx(opcode[2], opcode[1], mch);
		case 0x31: return and_indy(opcode[2], opcode[1], mch);
		case 0x0A: return asl_acc(mch);
		case 0x06: return asl_zp(opcode[1], mch);
		case 0x16: return asl_zpx(opcode[1], mch);
		case 0x0E: return asl_abs(opcode[2], opcode[1], mch);
		case 0x1E: return asl_absx(opcode[2], opcode[1], mch);
		case 0x90: return branch_clear(opcode[2], opcode[1], mch, 0b00000001);
		case 0xB0: return branch_set(opcode[2], opcode[1], mch, 0b00000001);
		case 0xF0: return branch_set(opcode[2], opcode[1], mch, 0b00000010);
		case 0x24: return bit_zp(opcode[1], mch);
		case 0x2C: return bit_abs(opcode[2], opcode[1], mch);
		case 0x30: return branch_set(opcode[2], opcode[1], mch, 0b10000000);
		case 0xD0: return branch_clear(opcode[2], opcode[1], mch, 0b00000010);
		case 0x10: return branch_clear(opcode[2], opcode[1], mch, 0b10000000);
		case 0x00: return brk(mch);
		case 0x50: return branch_clear(opcode[2], opcode[1], mch, 0b01000000);
		case 0x70: return branch_set(opcode[2], opcode[1], mch, 0b01000000);
		case 0x18: return clc(mch);
		case 0x58: return cli(mch);
		case 0xB8: return clv(mch);
		case 0xC9: return cmp_imm(opcode[1], mch);
		case 0xC5: return cmp_zp(opcode[1], mch);
		case 0xD5: return cmp_zpx(opcode[1], mch);
		case 0xCD: return cmp_abs(opcode[2], opcode[1], mch, 0, 0);
		case 0xDD: return cmp_abs(opcode[2], opcode[1], mch, 1, mch->X);
		case 0xD9: return cmp_abs(opcode[2], opcode[1], mch, 1, mch->Y);
		case 0xC1: return cmp_indy(opcode[2], opcode[1], mch);
		case 0xD1: return cmp_indx(opcode[2], opcode[1], mch);
		case 0xE0: return cpx_imm(opcode[1], mch);
		case 0xE4: return cpx_zp(opcode[1], mch);
		case 0xEC: return cpx_abs(opcode[2], opcode[1], mch);
		case 0xC0: return cpy_imm(opcode[1], mch);
		case 0xC4: return cpy_zp(opcode[1], mch);
		case 0xCC: return cpy_abs(opcode[2], opcode[1], mch);
		case 0xC6: return dec_zp(opcode[1], mch);
		case 0xD6: return dec_zpx(opcode[1], mch);
		case 0xCE: return dec_abs(opcode[2], opcode[1], mch);
		case 0xDE: return dec_absx(opcode[2], opcode[1], mch);
		case 0xCA: return dex(mch);
		case 0x88: return dey(mch);
		case 0x49: return eor_imm(opcode[1], mch);
		case 0x45: return eor_zp(opcode[1], mch);
		case 0x55: return eor_zpx(opcode[1], mch);
		case 0x4D: return eor_abs(opcode[2], opcode[1], mch);
		case 0x5D: return eor_absx(opcode[2], opcode[1], mch);
		case 0x59: return eor_absy(opcode[2], opcode[1], mch);
		case 0x41: return eor_indx(opcode[2], opcode[1], mch);
		case 0x51: return eor_indy(opcode[2], opcode[1], mch);
		case 0xE6: return inc_zp(opcode[1], mch, 0, 0);
		case 0xF6: return inc_zp(opcode[1], mch, 1, mch->X);
		case 0xEE: return inc_abs(opcode[2], opcode[1], mch, 0, 0);
		case 0xFE: return inc_abs(opcode[2], opcode[1], mch, 1, mch->X);
		case 0xE8: return inx(mch);
		case 0xC8: return iny(mch);
		case 0x4C: return jmp_abs(opcode[2], opcode[1], mch);
		case 0x6C: return jmp_ind(opcode[2], opcode[1], mch);
		case 0x20: return jsr(opcode[2], opcode[1], mch);
		case 0xA9: return lda_imm(opcode[1], mch);
		case 0xA5: return lda_zp(opcode[1], mch, 0, 0);
		case 0xB5: return lda_zp(opcode[1], mch, 1, mch->X);
		case 0xAD: return lda_abs(opcode[2], opcode[1], mch, 0, 0);
		case 0xBD: return lda_abs(opcode[2], opcode[1], mch, 1, mch->X);
		case 0xB9: return lda_abs(opcode[2], opcode[1], mch, 1, mch->Y);
		case 0xA1: return lda_indx(opcode[2], opcode[1], mch);
		case 0xB1: return lda_indy(opcode[2], opcode[1], mch);
		case 0xA2: return ldx_imm(opcode[1], mch);
		case 0xA6: return ldx_zp(opcode[1], mch, 0, 0);
		case 0xB6: return ldx_zp(opcode[1], mch, 1, mch->X);
		case 0xAE: return ldx_abs(opcode[2], opcode[1], mch, 0, 0);
		case 0xBE: return ldx_abs(opcode[2], opcode[1], mch, 1, mch->X);
		case 0xA0: return ldy_imm(opcode[1], mch);
		case 0xA4: return ldy_zp(opcode[1], mch, 0, 0);
		case 0xB4: return ldy_zp(opcode[1], mch, 1, mch->X);
		case 0xAC: return ldy_abs(opcode[2], opcode[1], mch, 0, 0);
		case 0xBC: return ldy_abs(opcode[2], opcode[1], mch, 1, mch->X);
		case 0x4A: return lsr_acc(mch);
		case 0x46: return lsr_zp(opcode[1], mch);
		case 0x56: return lsr_zpx(opcode[1], mch);
		case 0x4E: return lsr_abs(opcode[2], opcode[1], mch);
		case 0x5E: return lsr_absx(opcode[2], opcode[1], mch);
		case 0x09: return or_imm(opcode[1], mch);
		case 0x05: return or_zp(opcode[1], mch);
		case 0x15: return or_zpx(opcode[1], mch);
		case 0x0D: return or_abs(opcode[2], opcode[1], mch);
		case 0x1D: return or_absx(opcode[2], opcode[1], mch);
		case 0x19: return or_absy(opcode[2], opcode[1], mch);
		case 0x01: return or_indx(opcode[2], opcode[1], mch);
		case 0x11: return or_indy(opcode[2], opcode[1], mch);
		case 0x48: return pha(mch);
		case 0x08: return php(mch);
		case 0x68: return pla(mch);
		case 0x28: return plp(mch);
		case 0x40: return rti(mch);
		case 0x60: return rts(mch);
		case 0x78: return sei(mch); 
		case 0x38: return sec(mch);
		case 0xAA: return tax(mch);
		case 0xA8: return tay(mch);
		case 0x8A: return txa(mch);
		case 0x98: return tya(mch);

		default:
			fprintf(stdout, "unimplemented opcode!\n");
			fprintf(stdout, "opcode in question: %x\n", opcode[0]);
			exit(1);
			break;
	}
}
Esempio n. 3
0
/* Generate interrupts */
static void Interrupt(void)
{
	/* the 6805 latches interrupt requests internally, so we don't clear */
	/* pending_interrupts until the interrupt is taken, no matter what the */
	/* external IRQ pin does. */

#if (1) //HAS_HD63705)
	if( (m6805.pending_interrupts & (1<<HD63705_INT_NMI)) != 0)
	{
		PUSHWORD(m6805.pc);
		PUSHBYTE(m6805.x);
		PUSHBYTE(m6805.a);
		PUSHBYTE(m6805.cc);
        SEI;
		/* no vectors supported, just do the callback to clear irq_state if needed */
		if (m6805.irq_callback)
			(*m6805.irq_callback)(0);

		RM16( 0x1ffc, &pPC);
		change_pc(PC);
		m6805.pending_interrupts &= ~(1<<HD63705_INT_NMI);

		m6805_ICount -= 11;

	}
	else if( (m6805.pending_interrupts & ((1<<M6805_IRQ_LINE)|HD63705_INT_MASK)) != 0 ) {
		if ( (CC & IFLAG) == 0 ) {
#else
	if( (m6805.pending_interrupts & (1<<M6805_IRQ_LINE)) != 0 ) {
		if ( (CC & IFLAG) == 0 ) {
#endif
	{
        /* standard IRQ */
//#if (HAS_HD63705)
//      if(SUBTYPE!=SUBTYPE_HD63705)
//#endif
//          PC |= ~AMASK;
		PUSHWORD(m6805.pc);
		PUSHBYTE(m6805.x);
		PUSHBYTE(m6805.a);
		PUSHBYTE(m6805.cc);
        SEI;
		/* no vectors supported, just do the callback to clear irq_state if needed */
		if (m6805.irq_callback)
			(*m6805.irq_callback)(0);


//#if (HAS_HD63705)
		if(SUBTYPE==SUBTYPE_HD63705)
		{
			/* Need to add emulation of other interrupt sources here KW-2/4/99 */
			/* This is just a quick patch for Namco System 2 operation         */

			if((m6805.pending_interrupts&(1<<HD63705_INT_IRQ1))!=0)
			{
				m6805.pending_interrupts &= ~(1<<HD63705_INT_IRQ1);
				RM16( 0x1ff8, &pPC);
				change_pc(PC);
			}
			else if((m6805.pending_interrupts&(1<<HD63705_INT_IRQ2))!=0)
			{
				m6805.pending_interrupts &= ~(1<<HD63705_INT_IRQ2);
				RM16( 0x1fec, &pPC);
				change_pc(PC);
			}
			else if((m6805.pending_interrupts&(1<<HD63705_INT_ADCONV))!=0)
			{
				m6805.pending_interrupts &= ~(1<<HD63705_INT_ADCONV);
				RM16( 0x1fea, &pPC);
				change_pc(PC);
			}
			else if((m6805.pending_interrupts&(1<<HD63705_INT_TIMER1))!=0)
			{
				m6805.pending_interrupts &= ~(1<<HD63705_INT_TIMER1);
				RM16( 0x1ff6, &pPC);
				change_pc(PC);
			}
			else if((m6805.pending_interrupts&(1<<HD63705_INT_TIMER2))!=0)
			{
				m6805.pending_interrupts &= ~(1<<HD63705_INT_TIMER2);
				RM16( 0x1ff4, &pPC);
				change_pc(PC);
			}
			else if((m6805.pending_interrupts&(1<<HD63705_INT_TIMER3))!=0)
			{
				m6805.pending_interrupts &= ~(1<<HD63705_INT_TIMER3);
				RM16( 0x1ff2, &pPC);
				change_pc(PC);
			}
			else if((m6805.pending_interrupts&(1<<HD63705_INT_PCI))!=0)
			{
				m6805.pending_interrupts &= ~(1<<HD63705_INT_PCI);
				RM16( 0x1ff0, &pPC);
				change_pc(PC);
			}
			else if((m6805.pending_interrupts&(1<<HD63705_INT_SCI))!=0)
			{
				m6805.pending_interrupts &= ~(1<<HD63705_INT_SCI);
				RM16( 0x1fee, &pPC);
				change_pc(PC);
			}
		}
		else
//#endif
		{
			RM16( 0xffff - 5, &pPC );
			change_pc(PC);
		}

		}	// CC & IFLAG
			m6805.pending_interrupts &= ~(1<<M6805_IRQ_LINE);
		}
		m6805_ICount -= 11;
	}
}

static void m6805_reset()
{
	int (*save_irqcallback)(int) = m6805.irq_callback;
	memset(&m6805, 0, sizeof(m6805));
	m6805.irq_callback = save_irqcallback;
	/* Force CPU sub-type and relevant masks */
	m6805.subtype	= SUBTYPE_M6805;
	SP_MASK = 0x07f;
	SP_LOW	= 0x060;
	/* Initial stack pointer */
	S = SP_MASK;
	/* IRQ disabled */
    SEI;
	RM16( 0xfffe , &pPC );
	change_pc(PC);
}

void m6805Reset() {
	m6805_reset();
}

//static void m6805_init(int ) //int (*irqcallback)(int))
//{
//	m6805.irq_callback = irqcallback;
//}

//static void m6805_exit(void)
//{
//	/* nothing to do */
//}


void m6805SetIrqLine(int , int state)
{
	/* Basic 6805 only has one IRQ line */
	/* See HD63705 specific version     */
	if (m6805.irq_state[0] == state) return;

	m6805.irq_state[0] = state;
	if (state != CLEAR_LINE)
		m6805.pending_interrupts |= 1<<M6805_IRQ_LINE;
}


#include "6805ops.c"


/* execute instructions on this CPU until icount expires */
int m6805Run(int cycles)
{
	UINT8 ireg;
	m6805_ICount = cycles;

	do
	{
		if (m6805.pending_interrupts != 0)
		{
			if (SUBTYPE==SUBTYPE_M68705)
			{
				m68705_Interrupt();
			}
			else
			{
				Interrupt();
			}
		}

		ireg=M_RDOP(PC++);

		switch( ireg )
		{
			case 0x00: brset(0x01); break;
			case 0x01: brclr(0x01); break;
			case 0x02: brset(0x02); break;
			case 0x03: brclr(0x02); break;
			case 0x04: brset(0x04); break;
			case 0x05: brclr(0x04); break;
			case 0x06: brset(0x08); break;
			case 0x07: brclr(0x08); break;
			case 0x08: brset(0x10); break;
			case 0x09: brclr(0x10); break;
			case 0x0A: brset(0x20); break;
			case 0x0B: brclr(0x20); break;
			case 0x0C: brset(0x40); break;
			case 0x0D: brclr(0x40); break;
			case 0x0E: brset(0x80); break;
			case 0x0F: brclr(0x80); break;
			case 0x10: bset(0x01); break;
			case 0x11: bclr(0x01); break;
			case 0x12: bset(0x02); break;
			case 0x13: bclr(0x02); break;
			case 0x14: bset(0x04); break;
			case 0x15: bclr(0x04); break;
			case 0x16: bset(0x08); break;
			case 0x17: bclr(0x08); break;
			case 0x18: bset(0x10); break;
			case 0x19: bclr(0x10); break;
			case 0x1a: bset(0x20); break;
			case 0x1b: bclr(0x20); break;
			case 0x1c: bset(0x40); break;
			case 0x1d: bclr(0x40); break;
			case 0x1e: bset(0x80); break;
			case 0x1f: bclr(0x80); 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: bhcc(); break;
			case 0x29: bhcs(); break;
			case 0x2a: bpl(); break;
			case 0x2b: bmi(); break;
			case 0x2c: bmc(); break;
			case 0x2d: bms(); break;
			case 0x2e: bil(); break;
			case 0x2f: bih(); break;
			case 0x30: neg_di(); break;
			case 0x31: illegal(); break;
			case 0x32: illegal(); break;
			case 0x33: com_di(); break;
			case 0x34: lsr_di(); break;
			case 0x35: illegal(); break;
			case 0x36: ror_di(); break;
			case 0x37: asr_di(); break;
			case 0x38: lsl_di(); break;
			case 0x39: rol_di(); break;
			case 0x3a: dec_di(); break;
			case 0x3b: illegal(); break;
			case 0x3c: inc_di(); break;
			case 0x3d: tst_di(); break;
			case 0x3e: illegal(); break;
			case 0x3f: clr_di(); break;
			case 0x40: nega(); break;
			case 0x41: illegal(); break;
			case 0x42: illegal(); break;
			case 0x43: coma(); break;
			case 0x44: lsra(); break;
			case 0x45: illegal(); break;
			case 0x46: rora(); break;
			case 0x47: asra(); break;
			case 0x48: lsla(); break;
			case 0x49: rola(); break;
			case 0x4a: deca(); break;
			case 0x4b: illegal(); break;
			case 0x4c: inca(); break;
			case 0x4d: tsta(); break;
			case 0x4e: illegal(); break;
			case 0x4f: clra(); break;
			case 0x50: negx(); break;
			case 0x51: illegal(); break;
			case 0x52: illegal(); break;
			case 0x53: comx(); break;
			case 0x54: lsrx(); break;
			case 0x55: illegal(); break;
			case 0x56: rorx(); break;
			case 0x57: asrx(); break;
			case 0x58: aslx(); break;
			case 0x59: rolx(); break;
			case 0x5a: decx(); break;
			case 0x5b: illegal(); break;
			case 0x5c: incx(); break;
			case 0x5d: tstx(); break;
			case 0x5e: illegal(); break;
			case 0x5f: clrx(); break;
			case 0x60: neg_ix1(); break;
			case 0x61: illegal(); break;
			case 0x62: illegal(); break;
			case 0x63: com_ix1(); break;
			case 0x64: lsr_ix1(); break;
			case 0x65: illegal(); break;
			case 0x66: ror_ix1(); break;
			case 0x67: asr_ix1(); break;
			case 0x68: lsl_ix1(); break;
			case 0x69: rol_ix1(); break;
			case 0x6a: dec_ix1(); break;
			case 0x6b: illegal(); break;
			case 0x6c: inc_ix1(); break;
			case 0x6d: tst_ix1(); break;
			case 0x6e: illegal(); break;
			case 0x6f: clr_ix1(); break;
			case 0x70: neg_ix(); break;
			case 0x71: illegal(); break;
			case 0x72: illegal(); break;
			case 0x73: com_ix(); break;
			case 0x74: lsr_ix(); break;
			case 0x75: illegal(); break;
			case 0x76: ror_ix(); break;
			case 0x77: asr_ix(); break;
			case 0x78: lsl_ix(); break;
			case 0x79: rol_ix(); break;
			case 0x7a: dec_ix(); break;
			case 0x7b: illegal(); break;
			case 0x7c: inc_ix(); break;
			case 0x7d: tst_ix(); break;
			case 0x7e: illegal(); break;
			case 0x7f: clr_ix(); break;
			case 0x80: rti(); break;
			case 0x81: rts(); break;
			case 0x82: illegal(); break;
			case 0x83: swi(); break;
			case 0x84: illegal(); break;
			case 0x85: illegal(); break;
			case 0x86: illegal(); break;
			case 0x87: illegal(); break;
			case 0x88: illegal(); break;
			case 0x89: illegal(); break;
			case 0x8a: illegal(); break;
			case 0x8b: illegal(); break;
			case 0x8c: illegal(); break;
			case 0x8d: illegal(); break;
			case 0x8e: illegal(); break;
			case 0x8f: illegal(); break;
			case 0x90: illegal(); break;
			case 0x91: illegal(); break;
			case 0x92: illegal(); break;
			case 0x93: illegal(); break;
			case 0x94: illegal(); break;
			case 0x95: illegal(); break;
			case 0x96: illegal(); break;
			case 0x97: tax(); break;
			case 0x98: CLC; break;
			case 0x99: SEC; break;
#if IRQ_LEVEL_DETECT
			case 0x9a: CLI; if (m6805.irq_state != CLEAR_LINE) m6805.pending_interrupts |= 1<<M6805_IRQ_LINE; break;
#else
			case 0x9a: CLI; break;
#endif
			case 0x9b: SEI; break;
			case 0x9c: rsp(); break;
			case 0x9d: nop(); break;
			case 0x9e: illegal(); break;
			case 0x9f: txa(); break;
			case 0xa0: suba_im(); break;
			case 0xa1: cmpa_im(); break;
			case 0xa2: sbca_im(); break;
			case 0xa3: cpx_im(); break;
			case 0xa4: anda_im(); break;
			case 0xa5: bita_im(); break;
			case 0xa6: lda_im(); break;
			case 0xa7: illegal(); break;
			case 0xa8: eora_im(); break;
			case 0xa9: adca_im(); break;
			case 0xaa: ora_im(); break;
			case 0xab: adda_im(); break;
			case 0xac: illegal(); break;
			case 0xad: bsr(); break;
			case 0xae: ldx_im(); break;
			case 0xaf: illegal(); break;
			case 0xb0: suba_di(); break;
			case 0xb1: cmpa_di(); break;
			case 0xb2: sbca_di(); break;
			case 0xb3: cpx_di(); break;
			case 0xb4: anda_di(); break;
			case 0xb5: bita_di(); break;
			case 0xb6: lda_di(); break;
			case 0xb7: sta_di(); break;
			case 0xb8: eora_di(); break;
			case 0xb9: adca_di(); break;
			case 0xba: ora_di(); break;
			case 0xbb: adda_di(); break;
			case 0xbc: jmp_di(); break;
			case 0xbd: jsr_di(); break;
			case 0xbe: ldx_di(); break;
			case 0xbf: stx_di(); break;
			case 0xc0: suba_ex(); break;
			case 0xc1: cmpa_ex(); break;
			case 0xc2: sbca_ex(); break;
			case 0xc3: cpx_ex(); break;
			case 0xc4: anda_ex(); break;
			case 0xc5: bita_ex(); break;
			case 0xc6: lda_ex(); break;
			case 0xc7: sta_ex(); break;
			case 0xc8: eora_ex(); break;
			case 0xc9: adca_ex(); break;
			case 0xca: ora_ex(); break;
			case 0xcb: adda_ex(); break;
			case 0xcc: jmp_ex(); break;
			case 0xcd: jsr_ex(); break;
			case 0xce: ldx_ex(); break;
			case 0xcf: stx_ex(); break;
			case 0xd0: suba_ix2(); break;
			case 0xd1: cmpa_ix2(); break;
			case 0xd2: sbca_ix2(); break;
			case 0xd3: cpx_ix2(); break;
			case 0xd4: anda_ix2(); break;
			case 0xd5: bita_ix2(); break;
			case 0xd6: lda_ix2(); break;
			case 0xd7: sta_ix2(); break;
			case 0xd8: eora_ix2(); break;
			case 0xd9: adca_ix2(); break;
			case 0xda: ora_ix2(); break;
			case 0xdb: adda_ix2(); break;
			case 0xdc: jmp_ix2(); break;
			case 0xdd: jsr_ix2(); break;
			case 0xde: ldx_ix2(); break;
			case 0xdf: stx_ix2(); break;
			case 0xe0: suba_ix1(); break;
			case 0xe1: cmpa_ix1(); break;
			case 0xe2: sbca_ix1(); break;
			case 0xe3: cpx_ix1(); break;
			case 0xe4: anda_ix1(); break;
			case 0xe5: bita_ix1(); break;
			case 0xe6: lda_ix1(); break;
			case 0xe7: sta_ix1(); break;
			case 0xe8: eora_ix1(); break;
			case 0xe9: adca_ix1(); break;
			case 0xea: ora_ix1(); break;
			case 0xeb: adda_ix1(); break;
			case 0xec: jmp_ix1(); break;
			case 0xed: jsr_ix1(); break;
			case 0xee: ldx_ix1(); break;
			case 0xef: stx_ix1(); break;
			case 0xf0: suba_ix(); break;
			case 0xf1: cmpa_ix(); break;
			case 0xf2: sbca_ix(); break;
			case 0xf3: cpx_ix(); break;
			case 0xf4: anda_ix(); break;
			case 0xf5: bita_ix(); break;
			case 0xf6: lda_ix(); break;
			case 0xf7: sta_ix(); break;
			case 0xf8: eora_ix(); break;
			case 0xf9: adca_ix(); break;
			case 0xfa: ora_ix(); break;
			case 0xfb: adda_ix(); break;
			case 0xfc: jmp_ix(); break;
			case 0xfd: jsr_ix(); break;
			case 0xfe: ldx_ix(); break;
			case 0xff: stx_ix(); break;
		}
		m6805_ICount -= cycles1[ireg];
		m6805.nTotalCycles += cycles1[ireg];
	} while( m6805_ICount > 0 );

	return cycles - m6805_ICount;
}
Esempio n. 4
0
File: m6805.c Progetto: dinkc64/mame
/* execute instructions on this CPU until icount expires */
void m6805_base_device::execute_run()
{
	UINT8 ireg;

	S = SP_ADJUST( S );     /* Taken from CPU_SET_CONTEXT when pointer'afying */

	do
	{
		if (m_pending_interrupts != 0)
		{
			interrupt();
		}

		debugger_instruction_hook(this, PC);

		ireg=M_RDOP(PC++);

		switch( ireg )
		{
			case 0x00: brset(0x01); break;
			case 0x01: brclr(0x01); break;
			case 0x02: brset(0x02); break;
			case 0x03: brclr(0x02); break;
			case 0x04: brset(0x04); break;
			case 0x05: brclr(0x04); break;
			case 0x06: brset(0x08); break;
			case 0x07: brclr(0x08); break;
			case 0x08: brset(0x10); break;
			case 0x09: brclr(0x10); break;
			case 0x0A: brset(0x20); break;
			case 0x0B: brclr(0x20); break;
			case 0x0C: brset(0x40); break;
			case 0x0D: brclr(0x40); break;
			case 0x0E: brset(0x80); break;
			case 0x0F: brclr(0x80); break;
			case 0x10: bset(0x01); break;
			case 0x11: bclr(0x01); break;
			case 0x12: bset(0x02); break;
			case 0x13: bclr(0x02); break;
			case 0x14: bset(0x04); break;
			case 0x15: bclr(0x04); break;
			case 0x16: bset(0x08); break;
			case 0x17: bclr(0x08); break;
			case 0x18: bset(0x10); break;
			case 0x19: bclr(0x10); break;
			case 0x1a: bset(0x20); break;
			case 0x1b: bclr(0x20); break;
			case 0x1c: bset(0x40); break;
			case 0x1d: bclr(0x40); break;
			case 0x1e: bset(0x80); break;
			case 0x1f: bclr(0x80); 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: bhcc(); break;
			case 0x29: bhcs(); break;
			case 0x2a: bpl(); break;
			case 0x2b: bmi(); break;
			case 0x2c: bmc(); break;
			case 0x2d: bms(); break;
			case 0x2e: bil(); break;
			case 0x2f: bih(); break;
			case 0x30: neg_di(); break;
			case 0x31: illegal(); break;
			case 0x32: illegal(); break;
			case 0x33: com_di(); break;
			case 0x34: lsr_di(); break;
			case 0x35: illegal(); break;
			case 0x36: ror_di(); break;
			case 0x37: asr_di(); break;
			case 0x38: lsl_di(); break;
			case 0x39: rol_di(); break;
			case 0x3a: dec_di(); break;
			case 0x3b: illegal(); break;
			case 0x3c: inc_di(); break;
			case 0x3d: tst_di(); break;
			case 0x3e: illegal(); break;
			case 0x3f: clr_di(); break;
			case 0x40: nega(); break;
			case 0x41: illegal(); break;
			case 0x42: illegal(); break;
			case 0x43: coma(); break;
			case 0x44: lsra(); break;
			case 0x45: illegal(); break;
			case 0x46: rora(); break;
			case 0x47: asra(); break;
			case 0x48: lsla(); break;
			case 0x49: rola(); break;
			case 0x4a: deca(); break;
			case 0x4b: illegal(); break;
			case 0x4c: inca(); break;
			case 0x4d: tsta(); break;
			case 0x4e: illegal(); break;
			case 0x4f: clra(); break;
			case 0x50: negx(); break;
			case 0x51: illegal(); break;
			case 0x52: illegal(); break;
			case 0x53: comx(); break;
			case 0x54: lsrx(); break;
			case 0x55: illegal(); break;
			case 0x56: rorx(); break;
			case 0x57: asrx(); break;
			case 0x58: aslx(); break;
			case 0x59: rolx(); break;
			case 0x5a: decx(); break;
			case 0x5b: illegal(); break;
			case 0x5c: incx(); break;
			case 0x5d: tstx(); break;
			case 0x5e: illegal(); break;
			case 0x5f: clrx(); break;
			case 0x60: neg_ix1(); break;
			case 0x61: illegal(); break;
			case 0x62: illegal(); break;
			case 0x63: com_ix1(); break;
			case 0x64: lsr_ix1(); break;
			case 0x65: illegal(); break;
			case 0x66: ror_ix1(); break;
			case 0x67: asr_ix1(); break;
			case 0x68: lsl_ix1(); break;
			case 0x69: rol_ix1(); break;
			case 0x6a: dec_ix1(); break;
			case 0x6b: illegal(); break;
			case 0x6c: inc_ix1(); break;
			case 0x6d: tst_ix1(); break;
			case 0x6e: illegal(); break;
			case 0x6f: clr_ix1(); break;
			case 0x70: neg_ix(); break;
			case 0x71: illegal(); break;
			case 0x72: illegal(); break;
			case 0x73: com_ix(); break;
			case 0x74: lsr_ix(); break;
			case 0x75: illegal(); break;
			case 0x76: ror_ix(); break;
			case 0x77: asr_ix(); break;
			case 0x78: lsl_ix(); break;
			case 0x79: rol_ix(); break;
			case 0x7a: dec_ix(); break;
			case 0x7b: illegal(); break;
			case 0x7c: inc_ix(); break;
			case 0x7d: tst_ix(); break;
			case 0x7e: illegal(); break;
			case 0x7f: clr_ix(); break;
			case 0x80: rti(); break;
			case 0x81: rts(); break;
			case 0x82: illegal(); break;
			case 0x83: swi(); break;
			case 0x84: illegal(); break;
			case 0x85: illegal(); break;
			case 0x86: illegal(); break;
			case 0x87: illegal(); break;
			case 0x88: illegal(); break;
			case 0x89: illegal(); break;
			case 0x8a: illegal(); break;
			case 0x8b: illegal(); break;
			case 0x8c: illegal(); break;
			case 0x8d: illegal(); break;
			case 0x8e: illegal(); break;
			case 0x8f: illegal(); break;
			case 0x90: illegal(); break;
			case 0x91: illegal(); break;
			case 0x92: illegal(); break;
			case 0x93: illegal(); break;
			case 0x94: illegal(); break;
			case 0x95: illegal(); break;
			case 0x96: illegal(); break;
			case 0x97: tax(); break;
			case 0x98: CLC; break;
			case 0x99: SEC; break;
#if IRQ_LEVEL_DETECT
			case 0x9a: CLI; if (m_irq_state != CLEAR_LINE) m_pending_interrupts |= 1 << M6805_IRQ_LINE; break;
#else
			case 0x9a: CLI; break;
#endif
			case 0x9b: SEI; break;
			case 0x9c: rsp(); break;
			case 0x9d: nop(); break;
			case 0x9e: illegal(); break;
			case 0x9f: txa(); break;
			case 0xa0: suba_im(); break;
			case 0xa1: cmpa_im(); break;
			case 0xa2: sbca_im(); break;
			case 0xa3: cpx_im(); break;
			case 0xa4: anda_im(); break;
			case 0xa5: bita_im(); break;
			case 0xa6: lda_im(); break;
			case 0xa7: illegal(); break;
			case 0xa8: eora_im(); break;
			case 0xa9: adca_im(); break;
			case 0xaa: ora_im(); break;
			case 0xab: adda_im(); break;
			case 0xac: illegal(); break;
			case 0xad: bsr(); break;
			case 0xae: ldx_im(); break;
			case 0xaf: illegal(); break;
			case 0xb0: suba_di(); break;
			case 0xb1: cmpa_di(); break;
			case 0xb2: sbca_di(); break;
			case 0xb3: cpx_di(); break;
			case 0xb4: anda_di(); break;
			case 0xb5: bita_di(); break;
			case 0xb6: lda_di(); break;
			case 0xb7: sta_di(); break;
			case 0xb8: eora_di(); break;
			case 0xb9: adca_di(); break;
			case 0xba: ora_di(); break;
			case 0xbb: adda_di(); break;
			case 0xbc: jmp_di(); break;
			case 0xbd: jsr_di(); break;
			case 0xbe: ldx_di(); break;
			case 0xbf: stx_di(); break;
			case 0xc0: suba_ex(); break;
			case 0xc1: cmpa_ex(); break;
			case 0xc2: sbca_ex(); break;
			case 0xc3: cpx_ex(); break;
			case 0xc4: anda_ex(); break;
			case 0xc5: bita_ex(); break;
			case 0xc6: lda_ex(); break;
			case 0xc7: sta_ex(); break;
			case 0xc8: eora_ex(); break;
			case 0xc9: adca_ex(); break;
			case 0xca: ora_ex(); break;
			case 0xcb: adda_ex(); break;
			case 0xcc: jmp_ex(); break;
			case 0xcd: jsr_ex(); break;
			case 0xce: ldx_ex(); break;
			case 0xcf: stx_ex(); break;
			case 0xd0: suba_ix2(); break;
			case 0xd1: cmpa_ix2(); break;
			case 0xd2: sbca_ix2(); break;
			case 0xd3: cpx_ix2(); break;
			case 0xd4: anda_ix2(); break;
			case 0xd5: bita_ix2(); break;
			case 0xd6: lda_ix2(); break;
			case 0xd7: sta_ix2(); break;
			case 0xd8: eora_ix2(); break;
			case 0xd9: adca_ix2(); break;
			case 0xda: ora_ix2(); break;
			case 0xdb: adda_ix2(); break;
			case 0xdc: jmp_ix2(); break;
			case 0xdd: jsr_ix2(); break;
			case 0xde: ldx_ix2(); break;
			case 0xdf: stx_ix2(); break;
			case 0xe0: suba_ix1(); break;
			case 0xe1: cmpa_ix1(); break;
			case 0xe2: sbca_ix1(); break;
			case 0xe3: cpx_ix1(); break;
			case 0xe4: anda_ix1(); break;
			case 0xe5: bita_ix1(); break;
			case 0xe6: lda_ix1(); break;
			case 0xe7: sta_ix1(); break;
			case 0xe8: eora_ix1(); break;
			case 0xe9: adca_ix1(); break;
			case 0xea: ora_ix1(); break;
			case 0xeb: adda_ix1(); break;
			case 0xec: jmp_ix1(); break;
			case 0xed: jsr_ix1(); break;
			case 0xee: ldx_ix1(); break;
			case 0xef: stx_ix1(); break;
			case 0xf0: suba_ix(); break;
			case 0xf1: cmpa_ix(); break;
			case 0xf2: sbca_ix(); break;
			case 0xf3: cpx_ix(); break;
			case 0xf4: anda_ix(); break;
			case 0xf5: bita_ix(); break;
			case 0xf6: lda_ix(); break;
			case 0xf7: sta_ix(); break;
			case 0xf8: eora_ix(); break;
			case 0xf9: adca_ix(); break;
			case 0xfa: ora_ix(); break;
			case 0xfb: adda_ix(); break;
			case 0xfc: jmp_ix(); break;
			case 0xfd: jsr_ix(); break;
			case 0xfe: ldx_ix(); break;
			case 0xff: stx_ix(); break;
		}
		m_icount -= m_cycles1[ireg];
	} while( m_icount > 0 );
}
Esempio n. 5
0
/** 
 * @brief emulate instruction 
 * @return returns false if something goes wrong (e.g. illegal instruction)
 *
 * Current limitations:
 * 
 * - Illegal instructions are not implemented
 * - Excess cycles due to page boundary crossing are not calculated
 * - Some known architectural bugs are not emulated
 */
bool Cpu::emulate()
{
  /* fetch instruction */
  uint8_t insn = fetch_op();
  bool retval = true;
  /* emulate instruction */
  switch(insn)
  {
  /* BRK */
  case 0x0: brk(); break;
  /* ORA (nn,X) */
  case 0x1: ora(load_byte(addr_indx()),6); break;
  /* ORA nn */
  case 0x5: ora(load_byte(addr_zero()),3); break;
  /* ASL nn */
  case 0x6: asl_mem(addr_zero(),5); break;
  /* PHP */
  case 0x8: php(); break;
  /* ORA #nn */
  case 0x9: ora(fetch_op(),2); break;
  /* ASL A */
  case 0xA: asl_a(); break;
  /* ORA nnnn */
  case 0xD: ora(load_byte(addr_abs()),4); break;
  /* ASL nnnn */
  case 0xE: asl_mem(addr_abs(),6); break; 
  /* BPL nn */
  case 0x10: bpl(); break;
  /* ORA (nn,Y) */
  case 0x11: ora(load_byte(addr_indy()),5); break;
  /* ORA nn,X */
  case 0x15: ora(load_byte(addr_zerox()),4); break;
  /* ASL nn,X */
  case 0x16: asl_mem(addr_zerox(),6); break;
  /* CLC */
  case 0x18: clc(); break;
  /* ORA nnnn,Y */
  case 0x19: ora(load_byte(addr_absy()),4); break;
  /* ORA nnnn,X */
  case 0x1D: ora(load_byte(addr_absx()),4); break;
  /* ASL nnnn,X */
  case 0x1E: asl_mem(addr_absx(),7); break;
  /* JSR */
  case 0x20: jsr(); break;
  /* AND (nn,X) */
  case 0x21: _and(load_byte(addr_indx()),6); break;
  /* BIT nn */
  case 0x24: bit(addr_zero(),3); break;
  /* AND nn */
  case 0x25: _and(load_byte(addr_zero()),3); break;
  /* ROL nn */
  case 0x26: rol_mem(addr_zero(),5); break;
  /* PLP */
  case 0x28: plp(); break;
  /* AND #nn */
  case 0x29: _and(fetch_op(),2); break;
  /* ROL A */
  case 0x2A: rol_a(); break;
  /* BIT nnnn */
  case 0x2C: bit(addr_abs(),4); break;
  /* AND nnnn */
  case 0x2D: _and(load_byte(addr_abs()),4); break;
  /* ROL nnnn */
  case 0x2E: rol_mem(addr_abs(),6); break;
  /* BMI nn */
  case 0x30: bmi(); break;
  /* AND (nn,Y) */
  case 0x31: _and(load_byte(addr_indy()),5); break;               
  /* AND nn,X */
  case 0x35: _and(load_byte(addr_zerox()),4); break;
  /* ROL nn,X */
  case 0x36: rol_mem(addr_zerox(),6); break;
  /* SEC */
  case 0x38: sec(); break;
  /* AND nnnn,Y */
  case 0x39: _and(load_byte(addr_absy()),4); break;
  /* AND nnnn,X */
  case 0x3D: _and(load_byte(addr_absx()),4); break;
  /* ROL nnnn,X */
  case 0x3E: rol_mem(addr_absx(),7); break;
  /* RTI */
  case 0x40: rti(); break;
  /* EOR (nn,X) */
  case 0x41: eor(load_byte(addr_indx()),6); break;
  /* EOR nn */
  case 0x45: eor(load_byte(addr_zero()),3); break;
  /* LSR nn */
  case 0x46: lsr_mem(addr_zero(),5); break;
  /* PHA */
  case 0x48: pha(); break;
  /* EOR #nn */
  case 0x49: eor(fetch_op(),2); break;
  /* BVC */
  case 0x50: bvc(); break;
  /* JMP nnnn */
  case 0x4C: jmp(); break;
  /* EOR nnnn */
  case 0x4D: eor(load_byte(addr_abs()),4); break;
  /* LSR A */
  case 0x4A: lsr_a(); break;
  /* LSR nnnn */
  case 0x4E: lsr_mem(addr_abs(),6); break;
  /* EOR (nn,Y) */
  case 0x51: eor(load_byte(addr_indy()),5); break;
  /* EOR nn,X */
  case 0x55: eor(load_byte(addr_zerox()),4); break;
  /* LSR nn,X */
  case 0x56: lsr_mem(addr_zerox(),6); break;
  /* CLI */
  case 0x58: cli(); break;
  /* EOR nnnn,Y */
  case 0x59: eor(load_byte(addr_absy()),4); break;
  /* EOR nnnn,X */
  case 0x5D: eor(load_byte(addr_absx()),4); break;
  /* LSR nnnn,X */
  case 0x5E: lsr_mem(addr_absx(),7); break;
  /* RTS */
  case 0x60: rts(); break;
  /* ADC (nn,X) */
  case 0x61: adc(load_byte(addr_indx()),6); break;
  /* ADC nn */
  case 0x65: adc(load_byte(addr_zero()),3); break;
  /* ROR nn */
  case 0x66: ror_mem(addr_zero(),5); break;
  /* PLA */
  case 0x68: pla(); break;
  /* ADC #nn */
  case 0x69: adc(fetch_op(),2); break;
  /* ROR A */
  case 0x6A: ror_a(); break;
  /* JMP (nnnn) */
  case 0x6C: jmp_ind(); break;
  /* ADC nnnn */
  case 0x6D: adc(load_byte(addr_abs()),4); break;
  /* ROR nnnn */
  case 0x6E: ror_mem(addr_abs(),6); break;
  /* BVS */
  case 0x70: bvs(); break;
  /* ADC (nn,Y) */
  case 0x71: adc(load_byte(addr_indy()),5); break;
  /* ADC nn,X */
  case 0x75: adc(load_byte(addr_zerox()),4); break;
  /* ROR nn,X */
  case 0x76: ror_mem(addr_zerox(),6); break;
  /* SEI */
  case 0x78: sei(); break;
  /* ADC nnnn,Y */
  case 0x79: adc(load_byte(addr_absy()),4); break;
  /* ADC nnnn,X */
  case 0x7D: adc(load_byte(addr_absx()),4); break;
  /* ROR nnnn,X */
  case 0x7E: ror_mem(addr_absx(),7); break;
  /* STA (nn,X) */
  case 0x81: sta(addr_indx(),6); break;
  /* STY nn */
  case 0x84: sty(addr_zero(),3); break;
  /* STA nn */
  case 0x85: sta(addr_zero(),3); break;
  /* STX nn */
  case 0x86: stx(addr_zero(),3); break;
  /* DEY */
  case 0x88: dey(); break;
  /* TXA */
  case 0x8A: txa(); break;
  /* STY nnnn */
  case 0x8C: sty(addr_abs(),4); break;
  /* STA nnnn */
  case 0x8D: sta(addr_abs(),4); break;
  /* STX nnnn */
  case 0x8E: stx(addr_abs(),4); break;
  /* BCC nn */
  case 0x90: bcc(); break;
  /* STA (nn,Y) */
  case 0x91: sta(addr_indy(),6); break;
  /* STY nn,X */
  case 0x94: sty(addr_zerox(),4); break;
  /* STA nn,X */
  case 0x95: sta(addr_zerox(),4); break;
  /* STX nn,Y */
  case 0x96: stx(addr_zeroy(),4); break;
  /* TYA */
  case 0x98: tya(); break;
  /* STA nnnn,Y */
  case 0x99: sta(addr_absy(),5); break;
  /* TXS */
  case 0x9A: txs(); break;
  /* STA nnnn,X */
  case 0x9D: sta(addr_absx(),5); break;
  /* LDY #nn */
  case 0xA0: ldy(fetch_op(),2); break; 
  /* LDA (nn,X) */
  case 0xA1: lda(load_byte(addr_indx()),6); break;
  /* LDX #nn */
  case 0xA2: ldx(fetch_op(),2); break;
  /* LDY nn */
  case 0xA4: ldy(load_byte(addr_zero()),3); break;
  /* LDA nn */
  case 0xA5: lda(load_byte(addr_zero()),3); break;
  /* LDX nn */
  case 0xA6: ldx(load_byte(addr_zero()),3); break;
  /* TAY */
  case 0xA8: tay(); break;
  /* LDA #nn */
  case 0xA9: lda(fetch_op(),2); break;
  /* TAX */
  case 0xAA: tax(); break;
  /* LDY nnnn */
  case 0xAC: ldy(load_byte(addr_abs()),4); break;
  /* LDA nnnn */
  case 0xAD: lda(load_byte(addr_abs()),4); break;
  /* LDX nnnn */
  case 0xAE: ldx(load_byte(addr_abs()),4); break;
  /* BCS nn */
  case 0xB0: bcs(); break;
  /* LDA (nn,Y) */
  case 0xB1: lda(load_byte(addr_indy()),5); break;
  /* LDY nn,X */
  case 0xB4: ldy(load_byte(addr_zerox()),3); break;
  /* LDA nn,X */
  case 0xB5: lda(load_byte(addr_zerox()),3); break;
  /* LDX nn,Y */
  case 0xB6: ldx(load_byte(addr_zeroy()),3); break;
  /* CLV */
  case 0xB8: clv(); break;
  /* LDA nnnn,Y */
  case 0xB9: lda(load_byte(addr_absy()),4); break;
  /* TSX */
  case 0xBA: tsx(); break;
  /* LDY nnnn,X */
  case 0xBC: ldy(load_byte(addr_absx()),4); break;
  /* LDA nnnn,X */
  case 0xBD: lda(load_byte(addr_absx()),4); break;
  /* LDX nnnn,Y */
  case 0xBE: ldx(load_byte(addr_absy()),4); break;
  /* CPY #nn */
  case 0xC0: cpy(fetch_op(),2); break;
  /* CMP (nn,X) */
  case 0xC1: cmp(load_byte(addr_indx()),6); break;
  /* CPY nn */
  case 0xC4: cpy(load_byte(addr_zero()),3); break;
  /* CMP nn */
  case 0xC5: cmp(load_byte(addr_zero()),3); break;
  /* DEC nn */
  case 0xC6: dec(addr_zero(),5); break;
  /* INY */
  case 0xC8: iny(); break;
  /* CMP #nn */
  case 0xC9: cmp(fetch_op(),2); break;
  /* DEX */
  case 0xCA: dex(); break;
  /* CPY nnnn */
  case 0xCC: cpy(load_byte(addr_abs()),4); break;
  /* CMP nnnn */
  case 0xCD: cmp(load_byte(addr_abs()),4); break;
  /* DEC nnnn */
  case 0xCE: dec(addr_abs(),6); break;
  /* BNE nn */
  case 0xD0: bne(); break;
  /* CMP (nn,Y) */
  case 0xD1: cmp(load_byte(addr_indy()),5); break;
  /* CMP nn,X */
  case 0xD5: cmp(load_byte(addr_zerox()),4); break;
  /* DEC nn,X */
  case 0xD6: dec(addr_zerox(),6); break;
  /* CLD */
  case 0xD8: cld(); break;
  /* CMP nnnn,Y */
  case 0xD9: cmp(load_byte(addr_absy()),4); break;
  /* CMP nnnn,X */
  case 0xDD: cmp(load_byte(addr_absx()),4); break;
  /* DEC nnnn,X */
  case 0xDE: dec(addr_absx(),7); break;
  /* CPX #nn */
  case 0xE0: cpx(fetch_op(),2); break;
  /* SBC (nn,X) */
  case 0xE1: sbc(load_byte(addr_indx()),6); break;
  /* CPX nn */
  case 0xE4: cpx(load_byte(addr_zero()),3); break;
  /* SBC nn */
  case 0xE5: sbc(load_byte(addr_zero()),3); break;
  /* INC nn */
  case 0xE6: inc(addr_zero(),5); break;
  /* INX */
  case 0xE8: inx(); break;
  /* SBC #nn */
  case 0xE9: sbc(fetch_op(),2); break;
  /* NOP */
  case 0xEA: nop(); break;
  /* CPX nnnn */
  case 0xEC: cpx(load_byte(addr_abs()),4); break;
  /* SBC nnnn */
  case 0xED: sbc(load_byte(addr_abs()),4); break;
  /* INC nnnn */
  case 0xEE: inc(addr_abs(),6); break;
  /* BEQ nn */
  case 0xF0: beq(); break;
  /* SBC (nn,Y) */
  case 0xF1: sbc(load_byte(addr_indy()),5); break;
  /* SBC nn,X */
  case 0xF5: sbc(load_byte(addr_zerox()),4); break;
  /* INC nn,X */
  case 0xF6: inc(addr_zerox(),6); break;
  /* SED */
  case 0xF8: sed(); break;
  /* SBC nnnn,Y */
  case 0xF9: sbc(load_byte(addr_absy()),4); break;
  /* SBC nnnn,X */
  case 0xFD: sbc(load_byte(addr_absx()),4); break;
  /* INC nnnn,X */
  case 0xFE: inc(addr_absx(),7); break;
  /* Unknown or illegal instruction */
  default:
    D("Unknown instruction: %X at %04x\n", insn,pc());
    retval = false;
  }
  return retval;
}