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GETBS (Super FX): Difference between revisions
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'''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. | '''GETBS''' (Get Signed Byte) 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]]. | The reason the cycle times can vary is because of the [[ROM buffer]]. | ||
Revision as of 17:31, 9 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 cycles | ||
| Flags Affected | ||||||||
|---|---|---|---|---|---|---|---|---|
| B | ALT1 | ALT2 | O/V | S | CY | Z | ||
| 0 | 0 | 0 | . | . | . | . | ||
GETBS (Get Signed Byte) 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