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GETBH (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) | |||
|3DEF | |3DEF | ||
|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 | ||
|} | |} | ||
{| class="wikitable" style="float:right;clear:right;width:30%" | {| class="wikitable" style="float:right;clear:right;width:30%" | ||
!colspan="9"|Flags | !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 | ||
| Line 35: | Line 37: | ||
|} | |} | ||
'''GETBH''' is a [[Super FX]] instruction that loads one byte from the [[ROM buffer]] into the high byte of the [[destination register]] and the low byte of the [[source register]] into the low byte of the destination register. | '''GETBH''' (Get Byte High) is a [[Super FX]] instruction that loads one byte from the [[ROM buffer]] into the high byte of the [[destination register]] and the low byte of the [[source register]] into the low 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> | |||
GETBH | |||
</pre> | |||
[[File:gsu_getbh.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 GETBH: | |||
R<sub>6</sub> = 75bdh | |||
=== See Also === | === See Also === | ||
* [[GETB]] | * [[GETB]] | ||
* [[GETBL]] | * [[GETBL]] | ||
* [[GETBS]] | |||
* [[GETC]] | |||
* [[MERGE]] | |||
* [[ALT1]] | |||
=== External Links === | === External Links === | ||
* Official Super Nintendo development manual on GETBH: [https://archive.org/details/SNESDevManual/book2/page/n207 | * Official Super Nintendo development manual on GETBH: 9.36 on [https://archive.org/details/SNESDevManual/book2/page/n207 page 2-9-51 of Book II] | ||
* example: [https://archive.org/details/SNESDevManual/book2/page/n208 page 2-9-52 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 22:27, 16 July 2024
| Basic Info | |||||||
|---|---|---|---|---|---|---|---|
| Addressing Mode | Opcode | Length | ROM Speed | RAM Speed | Cache Speed | ||
| Implied (type 1) | 3DEF | 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 | . | . | . | . | ||
GETBH (Get Byte High) is a Super FX instruction that loads one byte from the ROM buffer into the high byte of the destination register and the low byte of the source register into the low 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
GETBH
Example
Let:
(ROM buffer) = 75h Sreg : R2 Dreg : R6 R2 = 4abdh
After executing GETBH:
R6 = 75bdh
See Also
External Links
- Official Super Nintendo development manual on GETBH: 9.36 on page 2-9-51 of Book II
- example: page 2-9-52 of Book II, lbid