We've just updated MediaWiki and its underlying software. If anything doesn't look or work quite right, please mention it to us. --RanAS
BVS: Difference between revisions
From SnesLab
(→See Also: BRA, CLV) |
(deindent cycle penalty) |
||
| (5 intermediate revisions by the same user not shown) | |||
| Line 46: | Line 46: | ||
</pre> | </pre> | ||
==== 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]]. | ||
| Line 57: | Line 57: | ||
=== External Links === | === External Links === | ||
* [[Eyes & Lichty]] | * [[Eyes & Lichty]], [https://archive.org/details/0893037893ProgrammingThe65816/page/440 page 440] on BVS | ||
* [[Labiak]] | * [[Labiak]], [https://archive.org/details/Programming_the_65816/page/n139 page 129] on BVS | ||
* [[MCS6500 Manual]] | * 4.1.2.7 on [[MCS6500 Manual]], [https://archive.org/details/mos_microcomputers_programming_manual/page/n56 page 41] on BVS | ||
* [[Carr]] | * [[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