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Instruction Set Description
4.6.2.12 CLRN
* CLRN
Clear negative bit
CLRN
Syntax
Operation
0
→
N
or
(.NOT.src .AND. dst
→
dst)
BIC #4,SR
Emulation
Description
The constant 04h is inverted (0FFFBh) and is logically ANDed with the destination
operand. The result is placed into the destination. The clear negative bit instruction is a
word instruction.
Status Bits
N:
Reset to 0
Z:
Not affected
C:
Not affected
V:
Not affected
Mode Bits
OSCOFF, CPUOFF, and GIE are not affected.
Example
The negative bit in the SR is cleared. This avoids special treatment with negative
numbers of the subroutine called.
CLRN
CALL
SUBR
......
......
SUBR
JN
SUBRET
; If input is negative: do nothing and return
......
......
......
SUBRET
RET
145
SLAU272C – May 2011 – Revised November 2013
CPUX
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