DEC (Super FX): Difference between revisions

Latest revision as of 18:43, 30 July 2024


Basic Info
Addressing Mode	Opcode	Length	ROM Speed	RAM Speed	Cache Speed
Implied (type 1)	En	1 byte	3 cycles	3 cycles	1 cycle


Flags Affected
B	ALT1	ALT2	O/V	S	CY	Z
0	0	0	.	S	.	Z

DEC is a Super FX instruction that decrements a register by one. The register selected can be from R₀ to R₁₄.

The ALT0 state is restored.

DEC Rn

Let:

R₉ = a3f7h

After executing DEC R₉:

R₉ = a3f6h

@@ Line 1: / Line 1: @@
-'''DEC''' is a [[Super FX]] instruction that decrements a register.
+{| 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)
+|En
+|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
+|.
+|Z
+|}
+'''DEC''' is a [[Super FX]] instruction that decrements a register by one.  The register selected can be from R<sub>0</sub> to R<sub>14</sub>.
+The [[ALT0]] state is restored.
+==== Syntax ====
+<pre>
+DEC Rn
+</pre>
+==== Example ====
+Let:
+ R<sub>9</sub> = a3f7h
+After executing DEC R<sub>9</sub>:
+ R<sub>9</sub> = a3f6h
+=== See Also ===
+* [[INC (Super FX)]]
+* [[DEC]]
+* [[DEC (SPC700)]]
+* [[DEX]]
+* [[DEY]]
+=== External Links ===
+* Official Nintendo documentation on DEC: 9.31 on [https://archive.org/details/SNESDevManual/book2/page/n199 page 2-9-43 of Book II]
 [[Category:ASM]]
 [[Category:Super FX]]
+[[Category:Arithmetic Operation Instructions]]
+[[Category:One-byte Instructions]]