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BCC: Difference between revisions
From SnesLab
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==== Cycle Penalties ==== | |||
* BCC takes one additional cycle if the branch is taken | |||
* BCC takes another extra cycle in [[emulation mode]] if that branch taken crosses a page boundary. | |||
=== See Also === | === See Also === | ||
Latest revision as of 02:37, 10 August 2024
| Basic Info | |||||||
|---|---|---|---|---|---|---|---|
| Addressing Mode | Opcode | Length | Speed | ||||
| Program Counter Relative | 90 | 2 bytes | 2 cycles* | ||||
| Flags Affected | ||||||||
|---|---|---|---|---|---|---|---|---|
| N | V | M | X | D | I | Z | C | |
| . | . | . | . | . | . | . | . | |
BCC (Branch if Carry Clear) is a 65x instruction that performs a jump if the carry flag is clear. An alternate mnemonic is "BLT."
If carry is set, control simply falls through to the next instruction.
No flags are affected.
Syntax
BCC nearlabel BLT nearlabel
Cycle Penalties
- BCC takes one additional cycle if the branch is taken
- BCC takes another extra cycle in emulation mode if that branch taken crosses a page boundary.
See Also
External Links
- Eyes & Lichty, page 428 on BCC
- Labiak, page 118 on BCC
- 4.1.2.3 on MCS6500 Manual, page 40 on BCC
- Carr, page 248 on BCC
- Leventhal, page 3-43 on BCC
- snes9x implementation of BCC: https://github.com/snes9xgit/snes9x/blob/master/cpuops.cpp#L1360