Datasheet

Instruction Set Description

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4.6.4.10 TSTA

* TSTA Test 20-bit destination register

TSTA Rdst

Syntax

Operation dst + 0FFFFFh + 1

dst + 0FFFFh + 1

dst + 0FFh + 1

CMPA #0,Rdst

Emulation

Description The destination register is compared with zero. The status bits are set according to the

result. The destination register is not affected.

Status Bits N: Set if destination register is negative, reset if positive

Z: Set if destination register contains zero, reset otherwise

C: Set

V: Reset

Mode Bits OSCOFF, CPUOFF, and GIE are not affected.

Example The 20-bit value in R7 is tested. If it is negative, continue at R7NEG; if it is positive but

not zero, continue at R7POS.

TSTA R7 ; Test R7

JN R7NEG ; R7 is negative

JZ R7ZERO ; R7 is zero

R7POS ...... ; R7 is positive but not zero

R7NEG ...... ; R7 is negative

R7ZERO ...... ; R7 is zero

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CPUX SLAU144J–December 2004–Revised July 2013

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