TST

Purpose

arithmetic compare of a scalar to 0.

Format

opcode src.rx

Operation

src ß 0;

Condition codes

N ß src LSS 0;

Z ß src EQL 0;

V ß 0;

C ß 0;

Exceptions

None (integer); Reserved operand (floating point)

Opcodes

95        TSTB   Test Byte

B5        TSTW  Test Word

D5       TSTL   Test Long

53        TSTF   Test Floating

73        TSTD   Test Double

Description

The condition codes are affected according to the value of the source operand.

Notes

1. TSTx src is equivalent to CMPx src, $0, but is shorter.

2. On a floating reserved operand, the condition codes are unpredictable.