Datasheet

Instruction Set Description

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4.6.2.25 JEQ, JZ

JEQ Jump if equal

JZ Jump if zero

JEQ label

Syntax

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.

188

CPUX SLAU144J–December 2004–Revised July 2013

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