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Fixed PHP to only modify B flag in byte written, status reg itself is unchanged 

* line #71: C7E8  68        PLA
* see http://visual6502.org/wiki/index.php?title=6502_BRK_and_B_bit
This commit is contained in:
Rob McMullen 2017-12-18 09:53:18 -08:00
parent 4bfc5655b6
commit 3471e9aa3a
1 changed files with 10 additions and 2 deletions
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12
6502.c
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@ -322,8 +322,16 @@ static void inst_PHA()
static void inst_PHP()
{
SR.bits.brk = 1; // this is slightly unexpected, but it's what the real hardware does.
stack_push(SR.byte);
union StatusReg pushed_sr;
// PHP sets the BRK flag in the byte that is pushed onto the stack,
// but doesn't affect the status register itself. this is slightly
// unexpected, but it's what the real hardware does.
//
// See http://visual6502.org/wiki/index.php?title=6502_BRK_and_B_bit
pushed_sr.byte = SR.byte;
pushed_sr.bits.brk = 1;
stack_push(pushed_sr.byte);
}
static void inst_PLA()