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NEGA
0 – (A) = (A) + 1 ⇒ A
Operation:
Description:
Replaces the content of accumulator A with its two's complement (the
value $80 is left unchanged).
Condition Codes and Boolean Formulas:
S
–
N:
Z:
V:
C:
Addressing Modes, Machine Code, and Execution Times:
Source Form
NEGA
MOTOROLA
6-148
Negate A
X
H
I
N
Z
∆
∆
–
–
–
Set if MSB of result is set; cleared otherwise.
Set if result is $00; cleared otherwise.
R7 • R6 • R5 • R4 • R3 • R2 • R1 • R0
Set if there is a two's complement overflow from the implied subtraction
from zero; cleared otherwise. Two's complement overflow occurs if
and only if (A) = $80.
R7 + R6 + R5 + R4 + R3 + R2 + R1 + R0
Set if there is a borrow in the implied subtraction from zero; cleared oth-
erwise. Set in all cases except when (A) = $00.
Address Mode
INH
INSTRUCTION GLOSSARY
V
C
∆
∆
Object Code
40
NEGA
Cycles
Access Detail
1
O
CPU12
REFERENCE MANUAL
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