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GETBL (Super FX): Difference between revisions
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!colspan="8"|Basic Info | !colspan="8"|Basic Info | ||
|+ | |+ | ||
|'''Addressing Mode''' | |||
|'''Opcode''' | |'''Opcode''' | ||
|'''Length''' | |'''Length''' | ||
| Line 8: | Line 9: | ||
|'''Cache Speed''' | |'''Cache Speed''' | ||
|+ | |+ | ||
|[[Implied]] (type 1) | |||
|3EEF | |3EEF | ||
|2 bytes | |2 bytes | ||
|6 to 10 cycles | |6 to 10 cycles | ||
|6 to 9 cycles | |6 to 9 cycles | ||
|2 to 6 | |2 to 6 cycles | ||
|} | |} | ||
| Line 18: | Line 20: | ||
!colspan="9"|Flags Affected | !colspan="9"|Flags Affected | ||
|+ | |+ | ||
|B | |[[B Flag|B]] | ||
|[[ALT1]] | |[[ALT1]] | ||
|[[ALT2]] | |[[ALT2]] | ||
|[[O/V]] | |[[O/V]] | ||
|S | |[[Sign Flag|S]] | ||
|[[CY]] | |[[CY]] | ||
|Z | |[[Zero Flag|Z]] | ||
|+ | |+ | ||
|0 | |0 | ||
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'''GETBL''' (Get Byte Low) is a [[Super FX]] instruction that loads one byte from the [[ROM buffer]] into the low byte of the [[destination register]]. GETBL also loads the high byte of the [[source register]] into the high byte of the destination register. | '''GETBL''' (Get Byte Low) is a [[Super FX]] instruction that loads one byte from the [[ROM buffer]] into the low byte of the [[destination register]]. GETBL also loads the high byte of the [[source register]] into the high byte of the destination register. | ||
The reason the cycle times can vary is because of the [[ROM buffer]]. The [[ALT0]] state is restored. | |||
The source and destination registers should be specified in advance using [[WITH]], [[FROM]], or [[TO]]. Otherwise, R<sub>0</sub> serves as the default. | |||
==== Syntax ==== | |||
<pre> | |||
GETBL | |||
</pre> | |||
[[File:gsu getbl.png]] | |||
==== Example ==== | |||
Let: | |||
(ROM Buffer) = 75h | |||
S<sub>reg</sub> : R<sub>2</sub> | |||
D<sub>reg</sub> : R<sub>6</sub> | |||
R<sub>2</sub> = 4abdh | |||
After executing GETBL: | |||
R<sub>6</sub> = 4a75h | |||
=== See Also === | === See Also === | ||
* [[GETB]] | * [[GETB]] | ||
* [[GETBH]] | * [[GETBH]] | ||
* [[GETBS]] | |||
* [[GETC]] | |||
* [[ALT2]] | |||
=== External Links === | === External Links === | ||
* Official Super Nintendo development manual on GETBL: [https://archive.org/details/SNESDevManual/book2/page/n209 page 2-9-53 of Book II] | * Official Super Nintendo development manual on GETBL: 9.37 on [https://archive.org/details/SNESDevManual/book2/page/n209 page 2-9-53 of Book II] | ||
* example: [https://archive.org/details/SNESDevManual/book2/page/n210 page 2-9-54 of Book II], lbid | |||
[[Category:ASM]] | [[Category:ASM]] | ||
[[Category:Super FX]] | [[Category:Super FX]] | ||
[[Category:Data Transfer Instructions]] | [[Category:Data Transfer Instructions]] | ||
[[Category:Two-byte Instructions]] | |||
[[Category:Expects Sreg/Dreg Prearranged]] | |||
Latest revision as of 22:19, 16 July 2024
| Basic Info | |||||||
|---|---|---|---|---|---|---|---|
| Addressing Mode | Opcode | Length | ROM Speed | RAM Speed | Cache Speed | ||
| Implied (type 1) | 3EEF | 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 | . | . | . | . | ||
GETBL (Get Byte Low) is a Super FX instruction that loads one byte from the ROM buffer into the low byte of the destination register. GETBL also loads the high byte of the source register into the high byte of the destination register.
The reason the cycle times can vary is because of the ROM buffer. The ALT0 state is restored.
The source and destination registers should be specified in advance using WITH, FROM, or TO. Otherwise, R0 serves as the default.
Syntax
GETBL
Example
Let:
(ROM Buffer) = 75h Sreg : R2 Dreg : R6 R2 = 4abdh
After executing GETBL:
R6 = 4a75h
See Also
External Links
- Official Super Nintendo development manual on GETBL: 9.37 on page 2-9-53 of Book II
- example: page 2-9-54 of Book II, lbid