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Introduce instruction-independent status adjustment functions.

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For now only for negative and zero. Also use them in LDA emulation.
This commit is contained in:
Radosław Kujawa 2017-01-20 10:25:19 +01:00
parent 5201cfdc87
commit 3bcc7bb096
3 changed files with 22 additions and 10 deletions
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12
src/emulation.c
View File

@ -10,16 +10,8 @@ emul_lda(rk65c02emu_t *e, instruction_t *i)
e->regs.A = instruction_data_read_1(e, &id, i);
/* adjust status flags */
if (e->regs.A & NEGATIVE)
e->regs.P |= P_NEGATIVE;
else
e->regs.P &= ~P_NEGATIVE;
if (e->regs.A == 0)
e->regs.P |= P_ZERO;
else
e->regs.P &= ~P_ZERO;
instruction_status_adjust_zero(e->regs.A);
instruction_status_adjust_negative(e->regs.A);
}
void

18
src/instruction.c
View File

@ -144,6 +144,24 @@ instruction_decode(uint8_t opcode)
return id;
}
void
instruction_status_adjust_zero(rk65c02emu_t *e, uint8_t regval)
{
if (regval == 0)
e->regs.P |= P_ZERO;
else
e->regs.P &= ~P_ZERO;
}
void
instruction_status_adjust_negative(rk65c02emu_t *e, uint8_t regval)
{
if (regval & NEGATIVE)
e->regs.P |= P_NEGATIVE;
else
e->regs.P &= ~P_NEGATIVE;
}
uint8_t
instruction_data_read_1(rk65c02emu_t *e, instrdef_t *id, instruction_t *i)
{

2
src/instruction.h
View File

@ -44,6 +44,8 @@ instrdef_t instruction_decode(uint8_t);
void instruction_print(instruction_t *);
void disassemble(bus_t *, uint16_t);
uint8_t instruction_data_read_1(rk65c02emu_t *, instrdef_t *, instruction_t *);
void instruction_status_adjust_zero(rk65c02emu_t *, uint8_t);
void instruction_status_adjust_negative(rk65c02emu_t *, uint8_t);
//void instruction_execute(rk65c02emu_t *, instruction_t *);
#endif /* _INSTRUCTION_H_ */