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DEX
(X) – $0001 ⇒ X
Operation:
Description:
Subtract one from index register X. LEAX –1,X can produce the same
result, but LEAX does not affect the Z bit. Although the LEAX instruction
is more flexible, DEX requires only one byte of object code.
Only the Z bit is set or cleared according to the result of this operation.
Condition Codes and Boolean Formulas:
S
–
Z:
Addressing Modes, Machine Code, and Execution Times:
Source Form
DEX
MOTOROLA
6-76
Decrement Index Register X
X
H
I
N
Z
∆
–
–
–
–
Set if result is $0000; cleared otherwise.
Address Mode
INH
INSTRUCTION GLOSSARY
V
C
–
–
Object Code
09
DEX
Cycles
Access Detail
1
O
CPU12
REFERENCE MANUAL
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