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8XC251SA, SB, SP, SQ USER'S MANUAL
Operation:
JB
(PC) ← (PC) + 3
IF (bit) = 1
THEN
JBC bit51,rel
JBC bit,rel
Function:
Jump if bit is set and clear bit
Description:
If the specified bit is one, branch to the specified address; otherwise proceed with the next
instruction. The bit is not cleared if it is already a zero. The branch destination is computed
by adding the signed relative displacement in the third instruction byte to the PC, after incre-
menting the PC to the first byte of the next instruction.
Note: When this instruction is used to test an output pin, the value used as the original data
is read from the output data latch, not the input pin.
Flags:
CY
—
Example:
The accumulator contains 56H (01010110B). After the instruction sequence
JBC ACC.3,LABEL1
JBC ACC.2,LABEL2
the accumulator contains 52H (01010010B) and program execution continues at label
LABEL2.
Variations
JBC bit51,rel
Not Taken
Bytes:
3
States:
4
[Encoding]
0 0 0 1
Hex Code in:
Binary Mode = [Encoding]
Source Mode = [Encoding]
Operation:
JBC
(PC) ← (PC) + 3
IF (bit51) = 1
THEN
A-66
(PC) ← (PC) + rel
AC
—
Binary Mode
Taken
3
7
0 0 0 0
(bit51) ← 0
(PC) ← (PC) + rel
OV
N
—
—
Source Mode
Not Taken
Taken
3
3
4
7
bit addr
rel. addr
Z
—
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