Siemens C500 User Manual page 66

JNB bit,rel
Function: Jump if bit is not set
Description: If the indicated bit is a zero, branch to the indicated address; otherwise proceed with
the next instruction. The branch destination is computed by adding the signed
relative-displacement in the third instruction byte to the PC, after incrementing the
PC to the first byte of the next instruction. The bit tested is not modified. No flags
are affected.
Example: The data present at input port 1 is 11001010 B . The accumulator holds 56 H
(01010110 B ). The instruction sequence
JNB
JNB
will cause program execution to continue at the instruction at label LABEL2.
Operation: JNB
(PC) ¬ (PC) + 3
if (bit) = 0
then (PC) ¬ (PC) + rel.
Encoding: 0 0 1 1
Bytes: 3
Cycles: 2
Semiconductor Group
P1.3,LABEL1
ACC.3,LABEL2
0 0 0 0 bit address
4-40
Instruction Set
C500 Family
rel. address
1998-04-01