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BVS: Difference between revisions
From SnesLab
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=== External Links === | === External Links === | ||
* [[Eyes & Lichty]] | * [[Eyes & Lichty]], [https://archive.org/details/0893037893ProgrammingThe65816/page/440 page 440] on BVS | ||
* [[Labiak]], [https://archive.org/details/Programming_the_65816/page/n139 page 129] on BVS | * [[Labiak]], [https://archive.org/details/Programming_the_65816/page/n139 page 129] on BVS | ||
* [[MCS6500 Manual]] page 41 on BVS: https://archive.org/details/mos_microcomputers_programming_manual/page/n56 | * [[MCS6500 Manual]] page 41 on BVS: https://archive.org/details/mos_microcomputers_programming_manual/page/n56 | ||
Revision as of 03:27, 8 August 2024
| Basic Info | |||||||
|---|---|---|---|---|---|---|---|
| Addressing Mode | Opcode | Length | Speed | ||||
| Program Counter Relative | 70 | 2 bytes | 2 cycles* | ||||
| Flags Affected | ||||||||
|---|---|---|---|---|---|---|---|---|
| N | V | M | X | D | I | Z | C | |
| . | . | . | . | . | . | . | . | |
BVS is a 65x instruction that performs a branch if the overflow flag is set.
If the overflow flag is clear, control simply falls through to the next instruction.
No flags are affected.
Syntax
BVS nearlabel
Cycle Penalties
- BVS takes one extra cycle if the branch is taken
- BVS takes another extra cycle if that branch taken crosses a page boundary in emulation mode.
See Also
External Links
- Eyes & Lichty, page 440 on BVS
- Labiak, page 129 on BVS
- MCS6500 Manual page 41 on BVS: https://archive.org/details/mos_microcomputers_programming_manual/page/n56
- Carr page 253 on BVS: https://archive.org/details/6502UsersManual/page/n266
- Leventhal page 3-51 on BVS: https://archive.org/details/6502-assembly-language-programming/page/n100
- snes9x implementation of BVS: https://github.com/snes9xgit/snes9x/blob/master/cpuops.cpp#L1400