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Implement indirect zero page with X and indirect zero page with Y addressing.

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This commit is contained in:
Radosław Kujawa 2017-01-23 10:29:19 +01:00
parent 3cbede06f8
commit 452e4b3806
1 changed files with 12 additions and 7 deletions
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19
src/instruction.c
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@ -189,7 +189,13 @@ instruction_data_write_1(rk65c02emu_t *e, instrdef_t *id, instruction_t *i, uint
case ACCUMULATOR:
case IMMEDIATE:
case IZPX:
iaddr = bus_read_1(e->bus, i->op1 + e->regs.X);
iaddr |= (bus_read_1(e->bus, i->op1 + e->regs.X + 1) << 8);
bus_write_1(e->bus, iaddr, val);
case IZPY:
iaddr = bus_read_1(e->bus, i->op1 + e->regs.Y);
iaddr |= (bus_read_1(e->bus, i->op1 + e->regs.Y + 1) << 8);
bus_write_1(e->bus, iaddr, val);
case RELATIVE:
case ABSOLUTEX:
case ABSOLUTEY:
@ -234,17 +240,16 @@ instruction_data_read_1(rk65c02emu_t *e, instrdef_t *id, instruction_t *i)
rv = bus_read_1(e->bus, iaddr);
break;
case IZPX:
/* ziaddr = bus_read_1(e->bus, i->op1 + e->regs.X);
ziaddr |= (bus_read_1(e->bus, i->op1 + e->regs.X + 1) << 8);
rv = bus_read_1(e->bus, ziaddr);
*/
/* XXX: what about page wraps / roll over */
iaddr = bus_read_1(e->bus, i->op1 + e->regs.X);
iaddr |= (bus_read_1(e->bus, i->op1 + e->regs.X + 1) << 8);
rv = bus_read_1(e->bus, iaddr);
break;
case IZPY:
/*
/* XXX: what about page wraps / roll over */
iaddr = bus_read_1(e->bus, i->op1 + e->regs.Y);
iaddr |= (bus_read_1(e->bus, i->op1 + e->regs.Y + 1) << 8);
rv = bus_read_1(e->bus, ziaddr);
*/
rv = bus_read_1(e->bus, iaddr);
break;
case ABSOLUTE:
rv = bus_read_1(e->bus, i->op1 + (i->op2 << 8));