DEX: Difference between revisions

Latest revision as of 20:09, 12 August 2024


Basic Info
Addressing Mode	Opcode	Length	Speed
Implied (type 1)	CA	1 byte	2 cycles


Flags Affected
N	V	M	X	D	I	Z	C
N	.	.	.	.	.	Z	.

DEX is a 65x instruction that decrements the X index register by one. DEX ignores the decimal flag. Unlike SBC, DEX never affects the carry flag.

Syntax

DEX

External Links

Eyes & Lichty, page 452 on DEX
Labiak, page 139 on DEX
7.6 on MCS6500 Manual, page 98 on DEX
Carr, page 258 on DEX
Leventhal, page 3-61 on DEX
snes9x implementation of DEX: https://github.com/snes9xgit/snes9x/blob/master/cpuops.cpp#L1484
Clark, Bruce. http://www.6502.org/tutorials/65c816opcodes.html#6.1.1.3

@@ Line 7: / Line 7: @@
 |'''Speed'''
 |+
-|implied
+|[[Implied]] (type 1)
 |CA
 |1 byte
@@ Line 14: / Line 14: @@
 {| class="wikitable" style="float:right;clear:right;width:30%"
-!colspan="8"|Flags Clobbered
+!colspan="8"|Flags Affected
+|+
+|[[N Flag|N]]
+|[[V Flag|V]]
+|[[M Flag|M]]
+|[[X Flag|X]]
+|[[D Flag|D]]
+|[[I Flag|I]]
+|[[Z Flag|Z]]
+|[[C Flag|C]]
 |+
 |N
-|V
-|M
-|X
-|D
-|I
-|Z
-|C
-|+
-|
 |.
 |.
@@ Line 31: / Line 31: @@
 |.
 |.
-|
+|Z
 |.
 |}
-'''DEX''' is a 65x instruction that decrements the [[X index register]] by one.
+'''DEX''' is a 65x instruction that decrements the [[X index register]] by one.  DEX ignores the [[decimal flag]].  Unlike [[SBC]], DEX never affects the [[carry flag]].
+==== Syntax ====
+<pre>
+DEX
+</pre>
 === See Also ===
+* [[DEC]]
 * [[DEY]]
 * [[INX]]
 * [[INY]]
+* [[DEC (SPC700)]]
+* [[DEC (Super FX)]]
 === External Links ===
-* [[Eyes & Lichty]] page on DEX: https://archive.org/details/0893037893ProgrammingThe65816/page/n478
+* [[Eyes & Lichty]], [https://archive.org/details/0893037893ProgrammingThe65816/page/452 page 452] on DEX
-* [[Labiak]] page on DEX: https://archive.org/details/Programming_the_65816/page/n149
+* [[Labiak]], [https://archive.org/details/Programming_the_65816/page/n149 page 139] on DEX
-* [[MCS6500 Manual]] page on DEX: https://archive.org/details/mos_microcomputers_programming_manual/page/n116
+* 7.6 on [[MCS6500 Manual]], [https://archive.org/details/mos_microcomputers_programming_manual/page/n116 page 98] on DEX
-* [[Carr]] page on DEX: https://archive.org/details/6502UsersManual/page/n271
+* [[Carr]], [https://archive.org/details/6502UsersManual/page/n271 page 258] on DEX
-* [[Leventhal]] page on DEX: https://archive.org/details/6502-assembly-language-programming/page/n110
+* [[Leventhal]], [https://archive.org/details/6502-assembly-language-programming/page/n110 page 3-61] on DEX
 * snes9x implementation of DEX: https://github.com/snes9xgit/snes9x/blob/master/cpuops.cpp#L1484
+* Clark, Bruce. http://www.6502.org/tutorials/65c816opcodes.html#6.1.1.3
 [[Category:ASM]]
 [[Category:Inherited from 6502]]
+[[Category:One-byte Instructions]]
+[[Category:Implied Instructions]]
+[[Category:Two-cycle Instructions]]