8051 Jump if Carry is Not Set

Jump if Carry is not set

JNC relative address
If the carry flag is a 0, JNC branches to the address indicated; otherwise, it proceeds with the next instruction. The branch destination is computed by adding the signal relative-displacement in the second instruction byte to the PC, after incrementing the PC twice to point to the next instruction. The carry flag is not modified.

Encoding: 0 1 0 1 0 0 0 0 rel. address

The carry flag is set. The following instruction sequence,

JNC LABEL1
CPL C
JNC LABEL2

clears the carry and causes program execution to continue at the instruction identified by the label LABEL2.

Example:

	ORG 0H
MAIN :
	MOV A, #0	; Clear accumulator
	MOV A, #83H
	ADD A, #2FH
	JNC LABEL1
	ADD A, #5H
LABEL1 :	SUBB A, #10H
	AJMP MAIN
	END

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Related topics:
8051 Unconditional and Conditional Jump   |   8051 Long Jump   |   8051 Absolute Jump   |   8051 Short Jump   |   8051 Indirect Jump   |   8051 Jump if Accumulator Zero   |   8051 Jump if Accumulator Not Zero   |   8051 Compare and Jump if Not Equal   |   8051 Decrement and Jump if Not Zero   |   8051 Jump if Carry is Set   |   8051 Jump if Bit Set   |   8051 Jump if Bit Not Set   |   8051 Jump if Bit is Set and Clear Bit

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List of topics: 8051

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