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SBCB
(B) – (M) – C ⇒ B
Operation:
Description:
Subtracts the content of memory location M and the value of the C status
bit from the content of accumulator B. The result is placed in B. For sub-
traction instructions, the C status bit represents a borrow.
Condition Codes and Boolean Formulas:
S
–
N:
Z:
V:
C:
Addressing Modes, Machine Code, and Execution Times:
Source Form
SBCB # opr8i
SBCB opr8a
SBCB opr16a
SBCB oprx0_xysp
SBCB oprx9 , xysp
SBCB oprx16 , xysp
SBCB [D ,xysp ]
SBCB [ oprx16,xysp ]
CPU12
REFERENCE MANUAL
Subtract with Carry from B
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 absolute value of the content of memory plus previous carry
is larger than the absolute value of the accumulator; cleared other-
wise.
Address Mode
IMM
DIR
EXT
IDX
IDX1
IDX2
[D,IDX]
[IDX2]
INSTRUCTION GLOSSARY
V
C
∆
∆
Object Code
C2 ii
D2 dd
F2 hh ll
E2 xb
E2 xb ff
E2 xb ee ff
E2 xb
E2 xb ee ff
SBCB
Cycles
Access Detail
1
P
3
rfP
3
rOP
3
rfP
3
rPO
4
frPP
6
fIfrfP
6
fIPrfP
MOTOROLA
6-181
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