Instruction Set Description
190
SLAU367P – October 2012 – Revised April 2020
Copyright © 2012–2020, Texas Instruments Incorporated
CPUX
4.6.2.30 JNC, JLO
JNC
Jump if no carry
JLO
Jump if lower (unsigned)
Syntax
JNC label
JLO label
Operation
If C = 0: PC + (2 × Offset)
→
PC
If C = 1: execute following instruction
Description
The carry bit C in the SR is tested. If it is reset, the signed 10-bit word offset contained in
the instruction is multiplied by 2, sign extended, and added to the 20-bit PC. This means
a jump in the range –511 to +512 words relative to the PC in the full memory range. If C
is set, the instruction after the jump is executed.
JNC is used for the test of the carry bit C.
JLO is used for the comparison of unsigned numbers.
Status Bits
Status bits are not affected.
Mode Bits
OSCOFF, CPUOFF, and GIE are not affected.
Example
If byte EDE < 15, the program continues at Label2. Unsigned data. Data in lower 64 K,
program in full memory range.
CMP.B
#15,&EDE
; Is EDE < 15? Info to C
JLO
Label2
; Yes, EDE < 15. C = 0
...
; No, EDE >= 15. Continue
Example
The word TONI is added to R5. If no carry occurs, continue at Label0. The address of
TONI is within PC ± 32 K.
ADD
TONI,R5
; TONI + R5 -> R5. Carry -> C
JNC
Label0
; No carry
...
; Carry = 1: continue here