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CMP (Super FX): Difference between revisions
From SnesLab
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|'''Cache Speed''' | |'''Cache Speed''' | ||
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|[[Implied]] | |[[Implied]] (type 1) | ||
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!colspan="9"|Flags Affected | !colspan="9"|Flags Affected | ||
|+ | |+ | ||
|B | |[[B Flag|B]] | ||
|[[ALT1]] | |[[ALT1]] | ||
|[[ALT2]] | |[[ALT2]] | ||
|[[O/V]] | |[[O/V]] | ||
|S | |[[Sign Flag|S]] | ||
|[[CY]] | |[[CY]] | ||
|Z | |[[Zero Flag|Z]] | ||
|+ | |+ | ||
|0 | |0 | ||
|0 | |0 | ||
|0 | |0 | ||
| | |O/V | ||
| | |S | ||
| | |CY | ||
| | |Z | ||
|} | |} | ||
'''CMP''' (Compare) is a [[Super FX]] instruction that compares the operand register with the [[source register]]. Internally, this is done via a subtraction, but the difference is not stored anywhere. | '''CMP''' (Compare) is a [[Super FX]] instruction that compares the operand register with the [[source register]]. Internally, this is done via a subtraction, but the difference is not stored anywhere. Thus, the purpose of CMP is to setup the flags. | ||
The operand serves as the subtrahend and can be any register from R<sub>0</sub> to R<sub>15</sup>. | |||
The [[ALT0]] state is restored. | |||
The source register should be specified in advance using [[WITH]] or [[FROM]]. Otherwise, R<sub>0</sub> serves as the default. | |||
==== Syntax ==== | |||
<pre> | |||
CMP Rn | |||
</pre> | |||
==== Example ==== | |||
Let: | |||
S<sub>reg</sub> : R<sub>1</sub> | |||
R<sub>1</sub> = 8000h | |||
R<sub>3</sub> = 2fffh | |||
After executing CMP R<sub>3</sub>, the overflow and carry flags are set but the sign and zero flags are clear. | |||
=== See Also === | === See Also === | ||
* [[CMP]] | * [[CMP]] | ||
* [[SUB]] | * [[SUB]] | ||
* [[SBC]] | |||
* [[ALT3]] | |||
=== External Links === | === External Links === | ||
* Official Nintendo documentation on CMP: [https://archive.org/details/SNESDevManual/book2/page/n197 | * Official Nintendo documentation on CMP: 9.29 on [https://archive.org/details/SNESDevManual/book2/page/n197 page 2-9-41 of Book II] | ||
[[Category:ASM]] | [[Category:ASM]] | ||
[[Category:Super FX]] | [[Category:Super FX]] | ||
[[Category:Two-byte Instructions]] | [[Category:Two-byte Instructions]] | ||
[[Category:Expects Sreg/Dreg Prearranged]] | |||
Latest revision as of 18:42, 30 July 2024
| Basic Info | |||||||
|---|---|---|---|---|---|---|---|
| Addressing Mode | Opcode | Length | ROM Speed | RAM Speed | Cache Speed | ||
| Implied (type 1) | 3F6n | 2 bytes | 6 cycles | 6 cycles | 2 cycles | ||
| Flags Affected | ||||||||
|---|---|---|---|---|---|---|---|---|
| B | ALT1 | ALT2 | O/V | S | CY | Z | ||
| 0 | 0 | 0 | O/V | S | CY | Z | ||
CMP (Compare) is a Super FX instruction that compares the operand register with the source register. Internally, this is done via a subtraction, but the difference is not stored anywhere. Thus, the purpose of CMP is to setup the flags.
The operand serves as the subtrahend and can be any register from R0 to R15.
The ALT0 state is restored.
The source register should be specified in advance using WITH or FROM. Otherwise, R0 serves as the default.
Syntax
CMP Rn
Example
Let:
Sreg : R1 R1 = 8000h R3 = 2fffh
After executing CMP R3, the overflow and carry flags are set but the sign and zero flags are clear.
See Also
External Links
- Official Nintendo documentation on CMP: 9.29 on page 2-9-41 of Book II