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Description:
If the indicated bit is a one, jump to the address indicated; 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 11001010B. The accumulator holds 56 (01010110B). The instruction sequence
JB P1.2,LABEL1
JB ACC.2,LABEL2
will cause program execution to branch to the instruction at label LABEL2.

Operation:
JB
(PC) = (PC) + 3
if (bit) = 1 then
(PC) = (PC) + rel

Encoding:
0 0 1 0 0 0 0 0 + bit address + rel. address

Bytes: 3

Cycles: 2

Microcontroller Instruction Set  (79 pages, 308 kbytes)