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BPL
From SnesLab
| Basic Info | |||||||
|---|---|---|---|---|---|---|---|
| Addressing Mode | Opcode | Length | Speed | ||||
| relative | 10 | 2 byte | 2 cycles* | ||||
| Flags Affected | ||||||||
|---|---|---|---|---|---|---|---|---|
| N | V | M | X | D | I | Z | C | |
| . | . | . | . | . | . | . | . | |
BPL (Branch if PLus) is a 65x instruction that performs a jump if the negative flag is clear. Note that zero is considered positive in the 65x architecture, so this instruction's behavior might be more accurately be described as "branch if non-negative."
Cycle Penalties
- BPL takes one additional cycle if the branch is taken
- BPL takes another extra cycle if that branch taken crosses a page boundary in emulation mode.
See Also
External Links
- Eyes & Lichty page on BPL: https://archive.org/details/0893037893ProgrammingThe65816/page/n460
- Labiak page on BPL: https://archive.org/details/Programming_the_65816/page/n133
- MCS6500 Manual page on BPL: https://archive.org/details/mos_microcomputers_programming_manual/page/n55
- Carr page on BPL: https://archive.org/details/6502UsersManual/page/n264
- Leventhal page on BPL: https://archive.org/details/6502-assembly-language-programming/page/n97
- snes9x implementation of BPL: https://github.com/snes9xgit/snes9x/blob/master/cpuops.cpp#L1385