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GETBS (Super FX): Difference between revisions
From SnesLab
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==== Example ==== | |||
Let: | |||
(ROM buffer) = 85h | |||
D<sub>reg</sub> : R<sub>8</sub> | |||
After executing GETBS: | |||
R<sub>8</sub> = ff85h | |||
[[File:gsu getbs.png]] | [[File:gsu getbs.png]] |
Revision as of 18:46, 8 July 2024
Basic Info | |||||||
---|---|---|---|---|---|---|---|
Addressing Mode | Opcode | Length | ROM Speed | RAM Speed | Cache Speed | ||
Implied (type 1) | 3FEF | 2 bytes | 6 to 10 cycles | 6 to 9 cycles | 2 to 6 cycle |
Flags Affected | ||||||||
---|---|---|---|---|---|---|---|---|
B | ALT1 | ALT2 | O/V | S | CY | Z | ||
0 | 0 | 0 | . | . | . | . |
GETBS is a Super FX instruction that loads one byte from the ROM buffer into the low byte of the destination register. Every bit of the high byte of the destination register becomes whatever bit 7 of that loaded byte is.
The reason the cycle times can vary is because of the ROM buffer.
Syntax
GETBS
Example
Let:
(ROM buffer) = 85h Dreg : R8
After executing GETBS:
R8 = ff85h
See Also
External Links
- Official Super Nintendo development manual on GETBS: 9.38 on page 2-9-55 of Book II
- example: page 2-9-56 of Book II, lbid