POP (SPC700): Difference between revisions

Latest revision as of 03:52, 9 August 2024


Basic Info
Addressing Mode	Opcode	Length	Speed
Accumulator	AE	1 byte	4 cycles
Stack - X	CE	1 byte	4 cycles
Stack - Y	EE	1 byte	4 cycles
Stack - PSW	8E	1 byte	4 cycles


Flags Affected
Operand is the PSW?	N	V	P	B	H	I	Z	C
yes	N	V	P	B	H	I	Z	C
no	.	.	.	.	.	.	.	.

POP is an SPC700 command that pops a byte from the stack, pulling it into a register. The target register can be:

The stack pointer is incremented by one before the value is pulled.

When the program status word is the operand, all the flags are naturally affected as that is the register they live in. Otherwise, no flags are affected.

Syntax

POP A
POP X
POP Y
POP PSW

References

Table C-17 in Appendix C-9 of Book I of the official Super Nintendo development manual
anomie: https://github.com/yupferris/TasmShiz/blob/master/spc700.txt#L536

@@ Line 1: / Line 1: @@
-{| class="wikitable" style="float:right;clear:right;width:30%"
+{| class="wikitable" style="float:right;clear:right;width:40%"
 !colspan="8"|Basic Info
 |+
@@ Line 7: / Line 7: @@
 |'''Speed'''
 |+
-|
+|[[Accumulator Addressing | Accumulator]]
-|
+|AE
+|1 byte
+|4 cycles
+|+
+|[[Stack Addressing | Stack]] - X
+|CE
+|1 byte
+|4 cycles
+|+
+|[[Stack Addressing | Stack]] - Y
+|EE
+|1 byte
+|4 cycles
+|+
+|[[Stack Addressing | Stack]] - PSW
+|8E
 |1 byte
 |4 cycles
 |}
-{| class="wikitable" style="float:right;clear:right;width:30%"
+{| class="wikitable" style="float:right;clear:right;width:40%"
-!colspan="8"|Flags Affected
+!colspan="9"|Flags Affected
+|+
+|Operand is the PSW?
+|[[Negative Flag|N]]
+|[[Overflow Flag|V]]
+|[[Direct Page Flag|P]]
+|[[Break Flag|B]]
+|[[Half-Carry Flag|H]]
+|[[Interrupt Enable Flag|I]]
+|[[Zero Flag|Z]]
+|[[Carry Flag|C]]
 |+
+|yes
 |N
 |V
@@ Line 25: / Line 51: @@
 |C
 |+
+|no
 |.
 |.
@@ Line 35: / Line 62: @@
 |}
-'''POP''' is an [[SPC700]] command that pops things from the stack, pulling them into registers.
+'''POP''' is an [[SPC700]] command that pops a byte from the [[stack]], pulling it into a register.  The target register can be:
+* the [[accumulator]]
+* the [[X Index Register]]
+* the [[Y Index Register]]
+* the [[program status word]]
+The [[stack pointer]] is incremented by one before the value is pulled.
+When the [[program status word]] is the operand, all the flags are naturally affected as that is the register they live in.  Otherwise, no flags are affected.
-When the [[Program Status Word]] is the operand, flags are affected.
+==== Syntax ====
+<pre>
+POP A
+POP X
+POP Y
+POP PSW
+</pre>
 === See Also ===
 * [[PUSH]]
+* [[PLA]]
+* [[PLX]]
+* [[PLY]]
+* [[PLP]]
 === References ===
-* [https://archive.org/details/SNESDevManual/book1/page/n234 Appendix C-9 of Book I] of the official Super Nintendo development manual
+* Table C-17 in [https://archive.org/details/SNESDevManual/book1/page/n234 Appendix C-9 of Book I] of the official Super Nintendo development manual
+* anomie: https://github.com/yupferris/TasmShiz/blob/master/spc700.txt#L536
 [[Category:ASM]]
 [[Category:SPC700]]
 [[Category:Stack Operation Commands]]
+[[Category:One-byte Instructions]]