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BEQ: Difference between revisions
From SnesLab
(pluralize bytes) |
(asterisk for cycle penalties) |
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|F0 | |F0 | ||
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|2 cycles | |2 cycles* | ||
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Revision as of 22:00, 6 July 2024
| Basic Info | |||||||
|---|---|---|---|---|---|---|---|
| Addressing Mode | Opcode | Length | Speed | ||||
| Program Counter Relative | F0 | 2 bytes | 2 cycles* | ||||
| Flags Affected | ||||||||
|---|---|---|---|---|---|---|---|---|
| N | V | M | X | D | I | Z | C | |
| . | . | . | . | . | . | . | . | |
BEQ (Branch if Equal) is a 65x instruction that performs a jump if the zero flag is set.
No flags are affected.
Cycle Penalties
- BEQ takes an extra cycle if the branch is taken
- BEQ takes another extra cycle if the branch taken crosses a page boundary in emulation mode
See Also
External Links
- Eyes & Lichty page 430, on BEQ: https://archive.org/details/0893037893ProgrammingThe65816/page/n456
- Labiak page 120 on BEQ: https://archive.org/details/Programming_the_65816/page/n130
- MCS6500 Manual page 41 on BEQ: https://archive.org/details/mos_microcomputers_programming_manual/page/n56
- Carr page 249 on BEQ: https://archive.org/details/6502UsersManual/page/n262
- Leventhal page 3-44 on BEQ: https://archive.org/details/6502-assembly-language-programming/page/n93
- snes9x implementation of BEQ: https://github.com/snes9xgit/snes9x/blob/master/cpuops.cpp#L1370