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BVC (Super FX): Difference between revisions
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!colspan="8"|Basic Info | !colspan="8"|Basic Info | ||
|+ | |+ | ||
|'''Addressing Mode''' | |||
|'''Opcode''' | |'''Opcode''' | ||
|'''Length''' | |'''Length''' | ||
| Line 10: | Line 9: | ||
|'''Cache Speed''' | |'''Cache Speed''' | ||
|+ | |+ | ||
|[[Program Counter Relative]] | |||
|0E?? | |0E?? | ||
|2 bytes | |2 bytes | ||
| Line 20: | Line 20: | ||
!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]] | ||
|+ | |+ | ||
|. | |. | ||
| Line 36: | Line 36: | ||
|. | |. | ||
|} | |} | ||
'''BVC''' (Branch Overflow Clear) is a [[Super FX]] instruction that performs a branch when the overflow flag ([[O/V]]) is clear. The instruction following BVC is already in the pipeline and will run even if the branch occurs. | |||
If the overflow flag is set, control simply falls through and the branch does not happen. | |||
No flags are affected. | |||
==== Syntax ==== | |||
<pre> | |||
BVC e | |||
</pre> | |||
where e is a relative offset from -128 to 127. | |||
==== Example ==== | |||
Let the O/V flag be clear. This instruction jumps the program forward 4 bytes: | |||
<pre> | |||
BVC $+4h | |||
</pre> | |||
=== See Also === | |||
* [[BVS (Super FX)]] | |||
* [[BVC]] | |||
=== External Links === | === External Links === | ||
* Official Nintendo documentation on BVC: https://archive.org/details/SNESDevManual/book2/page/n190 | * Official Nintendo documentation on BVC: 9.25 on [https://archive.org/details/SNESDevManual/book2/page/n190 Page 2-9-34 of Book II] | ||
* example: [https://archive.org/details/SNESDevManual/book2/page/n191 Page 2-9-35 of Book II], lbid. | |||
[[Category:Super FX]] | [[Category:Super FX]] | ||
[[Category:ASM]] | [[Category:ASM]] | ||
[[Category:Instructions with Delay Slots]] | |||
Latest revision as of 08:02, 14 July 2024
| Basic Info | |||||||
|---|---|---|---|---|---|---|---|
| Addressing Mode | Opcode | Length | ROM Speed | RAM Speed | Cache Speed | ||
| Program Counter Relative | 0E?? | 2 bytes | 6 cycles | 6 cycles | 2 cycles | ||
| Flags Affected | ||||||||
|---|---|---|---|---|---|---|---|---|
| B | ALT1 | ALT2 | O/V | S | CY | Z | ||
| . | . | . | . | . | . | . | ||
BVC (Branch Overflow Clear) is a Super FX instruction that performs a branch when the overflow flag (O/V) is clear. The instruction following BVC is already in the pipeline and will run even if the branch occurs.
If the overflow flag is set, control simply falls through and the branch does not happen.
No flags are affected.
Syntax
BVC e
where e is a relative offset from -128 to 127.
Example
Let the O/V flag be clear. This instruction jumps the program forward 4 bytes:
BVC $+4h
See Also
External Links
- Official Nintendo documentation on BVC: 9.25 on Page 2-9-34 of Book II
- example: Page 2-9-35 of Book II, lbid.