M166 Datasheet, PDF (75/127 Pages) Siemens Semiconductor Group – C16x Family of Siemens 16-Bit CMOS Single-Chip Microcontrollers

30Mar98@15:00h
C166 Family Instruction Set
Instruction Description
JBC
Relative Jump if Bit Set and Clear Bit
JBC
Syntax
Operation
Data Types
Description
JBC
op1, op2
IF (op1) = 1 THEN
(op1) = 0
(IP) ← (IP) + sign_extend (op2)
ELSE
Next Instruction
END IF
BIT
If the bit specified by op1 is set, program execution continues at the loca-
tion of the instruction pointer, IP, plus the specified displacement, op2.
The bit specified by op1 is cleared, 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 JBC instruction. If the specified bit was clear, the instruction fol-
lowing the JBC 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
JBC
bitaddr_Q.q, rel
Format
AA QQ rr q0
Bytes
4
Semiconductor Group
75
Version 1.2, 12.97