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Btst bit test btst – Motorola DSP96002 User Manual

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MOTOROLA

DSP96002 USER’S MANUAL

A - 63

BTST

Bit Test

BTST

Operation:

S{n}

C

S{n}

C

S{n}

C

S{n}

C

S{n}

C

S{n}

C

S{n}

C

Assembler Syntax:

BTST #bit,X: ea

BTST #bit,X: aa

BTST #bit,X: pp

BTST #bit,Y: ea

BTST #bit,Y: aa

BTST #bit,Y: pp

BTST #bit,S

Description:

The nth bit of the source operand is tested and the state of the nth bit is reflected in the C condition code

bit. All memory alterable addressing modes may be used. Register Direct, Absolute Short and I/O Short

addressing may also be used.

The bit to be tested is selected by an immediate bit number 0-31. When used with the appropriate rotate

instructions, this instruction is useful for serial to parallel conversions.

If the system stack register SSH is specified as a source operand, the system stack pointer SP is postdec-

remented by 1 after SSH is read.

CCR Condition Codes:

C

- Set if bit tested is set. Cleared otherwise.

V

- Not affected.

Z

- Not affected.

N

- Not affected.

I

- Not affected.

LR

- Not affected.

R

- Not affected.

A

- Not affected.

ER Status Bits: Not affected.

IER Flags: Not affected.