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BEQ: Difference between revisions
From SnesLab
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!colspan="9"|Flags Affected | !colspan="9"|Flags Affected | ||
|+ | |+ | ||
|N | |[[Negative Flag|N]] | ||
|V | |[[Overflow Flag|V]] | ||
|M | |[[M Flag|M]] | ||
|X | |[[X Flag|X]] | ||
|D | |[[Decimal Flag|D]] | ||
|I | |[[I Flag|I]] | ||
|Z | |[[Zero Flag|Z]] | ||
|C | |[[Carry Flag|C]] | ||
|+ | |+ | ||
|. | |. | ||
Revision as of 04:26, 27 November 2023
| Basic Info | |||||||
|---|---|---|---|---|---|---|---|
| Addressing Mode | Opcode | Length | Speed | ||||
| relative | F0 | 2 byte | 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.
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 on BEQ: https://archive.org/details/Programming_the_65816/page/n130
- MCS6500 Manual page on BEQ: https://archive.org/details/mos_microcomputers_programming_manual/page/n56
- Carr page on BEQ: https://archive.org/details/6502UsersManual/page/n262
- Leventhal page 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