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BVS: Difference between revisions
From SnesLab
(control falls through) |
(→External Links: de n'd page number) |
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| Line 55: | Line 55: | ||
=== External Links === | === External Links === | ||
* [[Eyes & Lichty]] page 440 on BVS: https://archive.org/details/0893037893ProgrammingThe65816/page/ | * [[Eyes & Lichty]] page 440 on BVS: https://archive.org/details/0893037893ProgrammingThe65816/page/440 | ||
* [[Labiak]] page 129 on BVS: https://archive.org/details/Programming_the_65816/page/n139 | * [[Labiak]] page 129 on BVS: https://archive.org/details/Programming_the_65816/page/n139 | ||
* [[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 18:42, 14 July 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: https://archive.org/details/0893037893ProgrammingThe65816/page/440
- Labiak page 129 on BVS: https://archive.org/details/Programming_the_65816/page/n139
- 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