M166 Datasheet, PDF (81/127 Pages) Siemens Semiconductor Group – C16x Family of Siemens 16-Bit CMOS Single-Chip Microcontrollers

30Mar98@15:00h
C166 Family Instruction Set
Instruction Description
JNBS
Relative Jump if Bit Clear and Set Bit
JNBS
Syntax
Operation
Data Types
Description
JNBS
op1, op2
IF (op1) = 0 THEN
(op1) = 1
(IP) ← (IP) + sign_extend (op2)
ELSE
Next Instruction
END IF
BIT
If the bit specified by op1 is clear, program execution continues at the
location of the instruction pointer, IP, plus the specified displacement, op2.
The bit specified by op1 is set, allowing implementation of semaphore
operations. The displacement is a two’s complement number which is sign
extended and counts the relative distance in words. The value of the IP
used in the target address calculation is the address of the instruction fol-
lowing the JNBS instruction. If the specified bit was set, the instruction fol-
lowing the JNBS instruction is executed.
Condition Flags
E
Z
V
C
N
0
B
0
0
B
Addressing Modes
E Always cleared.
Z Contains logical negation of the previous state of the specified bit.
V Always cleared.
C Always cleared.
N Contains the previous state of the specified bit.
Mnemonic
JNBS
bitaddr_Q.q, rel
Format
BA QQ rr q0
Bytes
4
Semiconductor Group
81
Version 1.2, 12.97