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30Mar98@15:00h
Semiconductor Group
112
Version 1.2, 12.97
C166 Family Instruction Set
Instruction Description
SUBCB
Integer Subtraction with Carry
SUBCB
Syntax
SUBCB
op1, op2
Operation
(op1)
←
(op1) - (op2) - (C)
Data Types
BYTE
Description
Performs a 2’s complement binary subtraction of the source operand
specified by op2 and the previously generated carry bit from the destina-
tion operand specified by op1. The result is then stored in op1. This
instruction can be used to perform multiple precision arithmetic.
E Set if the value of op2 represents the lowest possible negative number.
Cleared otherwise. Used to signal the end of a table.
Z Set if result equals zero. Cleared otherwise.
V Set if an arithmetic underflow occurred, ie. the result cannot be repre-
sented in the specified data type. Cleared otherwise.
C Set if a borrow is generated. Cleared otherwise.
N Set if the most significant bit of the result is set. Cleared otherwise.
Addressing Modes
Mnemonic
Format
Bytes
SUBCB
Rb
n
, Rb
m
31 nm
2
SUBCB
Rb
n
, [Rw
i
]
39 n:10ii
2
SUBCB
Rb
n
, [Rw
i
+]
39 n:11ii
2
SUBCB
Rb
n
, #data3
39 n:0###
2
SUBCB
reg, #data16
37 RR ## xx
4
SUBCB
reg, mem
33 RR MM MM
4
SUBCB
mem, reg
35 RR MM MM
4
Condition Flags
E
Z
V
C
N
*
*
*
S
*