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SUBA
(A) – (M) ⇒ A
Operation:
Description:
Subtracts the content of memory location M from the content of accumu-
lator A, and places the result in A. For subtraction instructions, the C sta-
tus bit represents a borrow.
Condition Codes and Boolean Formulas:
S
–
N:
Z:
V:
C:
Addressing Modes, Machine Code, and Execution Times:
Source Form
SUBA # opr8i
SUBA opr8a
SUBA opr16a
SUBA oprx0_xysp
SUBA oprx9,xysp
SUBA oprx16,xysp
SUBA [D ,xysp ]
SUBA [ oprx16,xysp ]
CPU12
REFERENCE MANUAL
Subtract A
X
H
I
N
Z
∆
∆
–
–
–
Set if MSB of result is set; cleared otherwise.
Set if result is $00; cleared otherwise.
X7 • M7 • R7 + X7 • M7 • R7
Set if a two's complement overflow resulted from the operation;
cleared otherwise.
X7 • M7 + M7 • R7 + R7 • X7
Set if the value of the content of memory is larger than the value of
the accumulator; cleared otherwise.
Address Mode
IMM
DIR
EXT
IDX
IDX1
IDX2
[D,IDX]
[IDX2]
INSTRUCTION GLOSSARY
V
C
∆
∆
Object Code
80 ii
90 dd
B0 hh ll
A0 xb
A0 xb ff
A0 xb ee ff
A0 xb
A0 xb ee ff
SUBA
Cycles
Access Detail
1
P
3
rfP
3
rOP
3
rfP
3
rPO
4
frPP
6
fIfrfP
6
fIPrfP
MOTOROLA
6-193
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