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SBC (Super FX): Difference between revisions
From SnesLab
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'''SBC''' (SuBtract with Carry) is a [[Super FX]] instruction that performs a subtraction with regards to the [[CY|carry flag]]. | '''SBC''' (SuBtract with Carry) is a [[Super FX]] instruction that performs a subtraction with regards to the [[CY|carry flag]]. | ||
Unlike [[ADD (Super FX)]], [[ADC (Super FX)]] and [[SUB (Super FX)]], this one can only be used with registers, not with constant values since since the ALT3 version of SUB is a [[CMP (Super FX)]] instead. | Unlike [[ADD (Super FX)]], [[ADC (Super FX)]] and [[SUB (Super FX)]], this one can only be used with registers, not with constant values since since the ALT3 version of SUB is a [[CMP (Super FX)]] instead. | ||
The source and destination registers should be specified in advance using [[WITH]], [[FROM]], or [[TO]]. Otherwise, R<sub>0</sub> serves as the default. | |||
==== Syntax ==== | ==== Syntax ==== |
Revision as of 18:57, 9 July 2024
Basic Info | |||||||
---|---|---|---|---|---|---|---|
Addressing Mode | Opcode | Length | ROM Speed | RAM Speed | Cache Speed | ||
3D6n | 2 bytes | 6 cycles | 6 cycles | 2 cycle |
Flags Affected | ||||||||
---|---|---|---|---|---|---|---|---|
B | ALT1 | ALT2 | O/V | S | CY | Z | ||
0 | 0 | 0 |
SBC (SuBtract with Carry) is a Super FX instruction that performs a subtraction with regards to the carry flag. Unlike ADD (Super FX), ADC (Super FX) and SUB (Super FX), this one can only be used with registers, not with constant values since since the ALT3 version of SUB is a CMP (Super FX) instead.
The source and destination registers should be specified in advance using WITH, FROM, or TO. Otherwise, R0 serves as the default.
Syntax
SBC Rn
See Also
Reference
- 9.78 on page 2-9-108 of Book II of the official Super Nintendo development manual