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BVS: Difference between revisions
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==== Cycle Penalties ==== | |||
* BVS takes one extra cycle if the branch is taken | * 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]]. | * BVS takes another extra cycle if that branch taken crosses a page boundary in [[emulation mode]]. | ||
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* 4.1.2.7 on [[MCS6500 Manual]], [https://archive.org/details/mos_microcomputers_programming_manual/page/n56 page 41] on BVS | * 4.1.2.7 on [[MCS6500 Manual]], [https://archive.org/details/mos_microcomputers_programming_manual/page/n56 page 41] on BVS | ||
* [[Carr]], [https://archive.org/details/6502UsersManual/page/n266 page 253] on BVS | * [[Carr]], [https://archive.org/details/6502UsersManual/page/n266 page 253] on BVS | ||
* [[Leventhal]] | * [[Leventhal]], [https://archive.org/details/6502-assembly-language-programming/page/n100 page 3-51] on BVS | ||
* snes9x implementation of BVS: https://github.com/snes9xgit/snes9x/blob/master/cpuops.cpp#L1400 | * snes9x implementation of BVS: https://github.com/snes9xgit/snes9x/blob/master/cpuops.cpp#L1400 | ||
Latest revision as of 17:42, 23 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
- 4.1.2.7 on MCS6500 Manual, page 41 on BVS
- Carr, page 253 on BVS
- Leventhal, page 3-51 on BVS
- snes9x implementation of BVS: https://github.com/snes9xgit/snes9x/blob/master/cpuops.cpp#L1400