INSTRUCTION SET DESCRIPTIONS

REP

Repeat Next Instruction

Instruction Format:

REP X:ea

REP Y:ea

Opcode:

REP

 

 

23

 

 

 

16

15

 

8

7

0

 

 

 

 

 

 

 

0 0 0 0 0 1 1 0

0 1 M M M R R R

0 s 1 0 0 0 0 0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Instruction Fields:

 

 

 

 

 

 

 

 

 

 

ea=6-bit Effective Address=MMMRRR,

 

 

 

Effective

 

 

 

 

 

 

 

 

 

 

Addressing Mode

M M M R R R

Memory Space

s

 

(Rn)-Nn

0

0

0

r

r

r

X Memory

 

0

 

(Rn)+Nn

0

0

1

r

r

r

Y Memory

 

1

 

(Rn)-

0

1

0

r

r

r

 

 

 

 

(Rn)+

0

1

1

r

r

r

 

 

 

 

(Rn)

1

0

0

r

r

r

 

 

 

 

(Rn+Nn)

1

0

1

r

r

r

 

 

 

 

-(Rn)

1

1

1

r

r

r

 

 

 

 

where “rrr” refers to an address register R0-R7

Timing: 4+mv oscillator clock cycles

Memory: 1 program word

MOTOROLA

INSTRUCTION SET DETAILS

A - 251

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Image 520
Motorola DSP56000, 24-Bit Digital Signal Processor manual REP Xea REP Yea