Instruction Set Description
257
SLAU208Q – June 2008 – Revised March 2018
Copyright © 2008–2018, Texas Instruments Incorporated
CPUX
6.6.2.25 JEQ, JZ
JEQ
Jump if equal
JZ
Jump if zero
Syntax
JEQ label
JZ label
Operation
If Z = 1: PC + (2 × Offset)
→
PC
If Z = 0: execute following instruction
Description
The zero bit Z in the SR is tested. If it is set, the signed 10-bit word offset contained in
the instruction is multiplied by two, 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 Z is reset, the instruction after the jump is executed.
JZ is used for the test of the zero bit Z.
JEQ is used for the comparison of operands.
Status Bits
Status bits are not affected
Mode Bits
OSCOFF, CPUOFF, and GIE are not affected.
Example
The state of the P2IN.0 bit defines the program flow.
BIT.B
#1,&P2IN
; Port 2, bit 0 reset?
JZ
Label1
; Yes, proceed at Label1
...
; No, set, continue
Example
If R5 = 15000h (20-bit data), the program continues at Label2.
CMPA
#15000h,R5
; Is R5 = 15000h? Info to SR
JEQ
Label2
; Yes, R5 = 15000h. Z = 1
...
; No, R5 not equal 15000h. Continue
Example
R7 (20-bit counter) is incremented. If its content is zero, the program continues at
Label4.
ADDA
#1,R7
; Increment R7
JZ
Label4
; Zero reached: Go to Label4
...
; R7 not equal 0. Continue here.