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: @@
-{| class="wikitable" style="float:right;clear:right;width:40%"
+{| class="wikitable" style="float:right;clear:right;width:50%"
 !colspan="8"|Basic Info
 |+
+|'''Addressing Mode'''
 |'''Opcode'''
 |'''Length'''
@@ Line 8: / Line 9: @@
 |'''Cache Speed'''
 |+
+|[[Implied]] (type 1)
 |En
 |1 byte
@@ Line 18: / Line 20: @@
 !colspan="9"|Flags Affected
 |+
-|B
+|[[B Flag|B]]
 |[[ALT1]]
 |[[ALT2]]
 |[[O/V]]
-|S
+|[[Sign Flag|S]]
 |[[CY]]
-|Z
+|[[Zero Flag|Z]]
 |+
 |0
@@ Line 30: / Line 32: @@
 |0
 |.
-|
+|S
 |.
-|
+|Z
 |}
-'''DEC''' is a [[Super FX]] instruction that decrements a register.
+'''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: [https://archive.org/details/SNESDevManual/book2/page/n199 Page 2-9-43 of Book II]
+* 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]]