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LSR (Super FX): Difference between revisions
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{| class="wikitable" style="float:right;clear:right;width: | {| class="wikitable" style="float:right;clear:right;width:50%" | ||
!colspan="8"|Basic Info | !colspan="8"|Basic Info | ||
|+ | |+ | ||
|'''Addressing Mode''' | |||
|'''Opcode''' | |'''Opcode''' | ||
|'''Length''' | |'''Length''' | ||
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|'''Cache Speed''' | |'''Cache Speed''' | ||
|+ | |+ | ||
|[[Implied]] (type 1) | |||
|03 | |03 | ||
|1 byte | |1 byte | ||
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!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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|. | |. | ||
|0 | |0 | ||
| | |CY | ||
| | |Z | ||
|} | |} | ||
'''LSR''' (Logical Shift Right) is a [[Super FX]] instruction that shifts all bits of the [[source register]]'s value to the right one bit while shifting a zero into the most significant bit, storing the result in the [[destination register]]. Bit 0 is shifted into [[CY]]. The source register itself is left unchanged. | '''LSR''' (Logical Shift Right) is a [[Super FX]] instruction that shifts all bits of the [[source register]]'s value to the right one bit while shifting a zero into the most significant bit, storing the result in the [[destination register]]. Bit 0 is shifted into [[CY]]. The source register itself is left unchanged. | ||
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> | |||
LSR | |||
</pre> | |||
==== Example ==== | |||
Let: | |||
S<sub>reg</sub> : R<sub>8</sub> | |||
D<sub>reg</sub> : R<sub>0</sub> | |||
R<sub>8</sub> = b53fh (1011 0101 0011 1111b) | |||
After executing LSR: | |||
R<sub>0</sub> = 5a9fh (0101 1010 1001 1111b) | |||
CY = 1 | |||
[[File:gsu_lsr.png]] | [[File:gsu_lsr.png]] | ||
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* [[DIV2]] | * [[DIV2]] | ||
* [[LSR]] | * [[LSR]] | ||
* [[LSR (SPC700)]] | |||
* [[ROR (Super FX)]] | |||
* [[ROL (Super FX)]] | |||
* [[ROR]] | |||
=== External Links === | === External Links === | ||
* Official Nintendo documentation on LSR: [https://archive.org/details/SNESDevManual/book2/page/n234 | * Official Nintendo documentation on LSR: 9.55 on [https://archive.org/details/SNESDevManual/book2/page/n234 page 2-9-78 of Book II] | ||
[[Category:ASM]] | [[Category:ASM]] | ||
| Line 51: | Line 75: | ||
[[Category:Shift Instructions]] | [[Category:Shift Instructions]] | ||
[[Category:One-byte Instructions]] | [[Category:One-byte Instructions]] | ||
[[Category:Expects Sreg/Dreg Prearranged]] | |||
Latest revision as of 02:01, 22 August 2024
| Basic Info | |||||||
|---|---|---|---|---|---|---|---|
| Addressing Mode | Opcode | Length | ROM Speed | RAM Speed | Cache Speed | ||
| Implied (type 1) | 03 | 1 byte | 3 cycles | 3 cycles | 1 cycle | ||
| Flags Affected | ||||||||
|---|---|---|---|---|---|---|---|---|
| B | ALT1 | ALT2 | O/V | S | CY | Z | ||
| 0 | 0 | 0 | . | 0 | CY | Z | ||
LSR (Logical Shift Right) is a Super FX instruction that shifts all bits of the source register's value to the right one bit while shifting a zero into the most significant bit, storing the result in the destination register. Bit 0 is shifted into CY. The source register itself is left unchanged.
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
LSR
Example
Let:
Sreg : R8 Dreg : R0 R8 = b53fh (1011 0101 0011 1111b)
After executing LSR:
R0 = 5a9fh (0101 1010 1001 1111b) CY = 1
See Also
External Links
- Official Nintendo documentation on LSR: 9.55 on page 2-9-78 of Book II