PHD: Difference between revisions

Latest revision as of 01:04, 13 August 2024


Basic Info
Addressing Mode	Opcode	Length	Speed
Stack (Push)	0B	1 byte	4 cycles


Flags Affected
N	V	M	X	D	I	Z	C
.	.	.	.	.	.	.	.

PHD (PusH Direct Page) is a 65c816 instruction that pushes the value of the direct page register onto the stack. The high byte is pushed before the low byte. The stack pointer is decremented by two.

No flags are affected.

Syntax

PHD

PHD works even in emulation mode, and will not push zero if the direct page has been relocated, as instructions that used zero page addressing on the 6502 will use direct page addressing instead with the direct offset still added into their effective address.

External Links

Eyes & Lichty, page 478 on PHD
Labiak, page 162 on PHD
snes9x implementation of PHD: https://github.com/snes9xgit/snes9x/blob/master/cpuops.cpp#L1786
Clark, Bruce. http://www.6502.org/tutorials/65c816opcodes.html#6.8.3

@@ Line 44: / Line 44: @@
 </pre>
-PHD works even in [[emulation mode]], and instructions that used [[zero page addressing]] on the 6502 will use [[direct page addressing]] instead with the direct offset still added into their effective address.
+PHD works even in [[emulation mode]], and will not push zero if the [[direct page]] has been relocated, as instructions that used [[zero page addressing]] on the 6502 will use [[direct page addressing]] instead with the direct offset still added into their effective address.
 === See Also ===