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ASR (Super FX): Difference between revisions
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'''ASR''' (Arithmetic Shift Right) is a [[Super FX]] instruction that shifts all bits to the right. | {| class="wikitable" style="float:right;clear:right;width:50%" | ||
!colspan="8"|Basic Info | |||
|+ | |||
|'''Addressing Mode''' | |||
|'''Opcode''' | |||
|'''Length''' | |||
|'''ROM Speed''' | |||
|'''RAM Speed''' | |||
|'''Cache Speed''' | |||
|+ | |||
|[[Implied]] (type 1) | |||
|96 | |||
|1 byte | |||
|3 cycles | |||
|3 cycles | |||
|1 cycle | |||
|} | |||
{| class="wikitable" style="float:right;clear:right;width:30%" | |||
!colspan="9"|Flags Affected | |||
|+ | |||
|[[B Flag|B]] | |||
|[[ALT1]] | |||
|[[ALT2]] | |||
|[[O/V]] | |||
|[[Sign Flag|S]] | |||
|[[CY]] | |||
|[[Zero Flag|Z]] | |||
|+ | |||
|0 | |||
|0 | |||
|0 | |||
|. | |||
|S | |||
|CY | |||
|Z | |||
|} | |||
'''ASR''' (Arithmetic Shift Right) is a [[Super FX]] instruction that shifts all bits of the [[source register]]'s value to the right one bit while also leaving the most significant bit unchanged, storing the result in the [[destination register]]. Bit 0 is shifted into [[CY]]. | |||
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> | |||
ASR | |||
</pre> | |||
==== Example ==== | |||
Let: | |||
S<sub>reg</sub> : R<sub>10</sub> | |||
D<sub>reg</sub> : R<sub>1</sub> | |||
CY = 0 | |||
R<sub>10</sub> = 4f7bh (0100 1111 0111 1011b) | |||
After executing ASR: | |||
CY = 1 | |||
R<sub>1</sub> = 27bdh (0010 0111 1011 1101b) | |||
[[File:gsu_asr.png]] | |||
The source register itself is not modified despite the arrows in the above image. | |||
=== See Also === | === See Also === | ||
* [[LSR (Super FX)]] | |||
* [[ASL]] | * [[ASL]] | ||
* [[LSR]] | * [[LSR]] | ||
* [[DIV2]] | |||
* [[ROR (Super FX)]] | |||
* [[ROR (SPC700)]] | |||
* [[ROR]] | |||
=== External Links === | |||
* Official Nintendo documentation on ASR: 9.13 on [https://archive.org/details/SNESDevManual/book2/page/n168 Page 2-9-12 of Book II] | |||
* example: [https://archive.org/details/SNESDevManual/book2/page/n169 page 2-9-13 of Book II], lbid. | |||
[[Category:ASM]] | [[Category:ASM]] | ||
[[Category: | [[Category:Super FX]] | ||
[[Category:Shift Instructions]] | |||
[[Category:One-byte Instructions]] | |||
[[Category:Expects Sreg/Dreg Prearranged]] | |||
Latest revision as of 02:04, 22 August 2024
| Basic Info | |||||||
|---|---|---|---|---|---|---|---|
| Addressing Mode | Opcode | Length | ROM Speed | RAM Speed | Cache Speed | ||
| Implied (type 1) | 96 | 1 byte | 3 cycles | 3 cycles | 1 cycle | ||
| Flags Affected | ||||||||
|---|---|---|---|---|---|---|---|---|
| B | ALT1 | ALT2 | O/V | S | CY | Z | ||
| 0 | 0 | 0 | . | S | CY | Z | ||
ASR (Arithmetic Shift Right) is a Super FX instruction that shifts all bits of the source register's value to the right one bit while also leaving the most significant bit unchanged, storing the result in the destination register. Bit 0 is shifted into CY.
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
ASR
Example
Let:
Sreg : R10 Dreg : R1 CY = 0 R10 = 4f7bh (0100 1111 0111 1011b)
After executing ASR:
CY = 1 R1 = 27bdh (0010 0111 1011 1101b)
The source register itself is not modified despite the arrows in the above image.
See Also
External Links
- Official Nintendo documentation on ASR: 9.13 on Page 2-9-12 of Book II
- example: page 2-9-13 of Book II, lbid.