INSTRUCTION DESCRIPTIONS

JSR

Jump to Subroutine

Instruction Format:

JSR xxx

Opcode:

JSR

 

23

16

15

 

 

8

7

 

0

 

0 0 0 0 1 1 0

1

0 0 0

0

a

a a a

a

a

a a a a a a

 

 

 

 

 

 

 

 

 

 

 

 

Instruction Fields:

xxx=12-bit Short Jump Address=aaaaaaaaaaaa

Timing: 4+jx oscillator clock cycles

Memory: 1+ea program words

Instruction Format:

JSR ea

Opcode:

 

23

16

15

8

7

0

 

 

 

 

 

 

 

 

0

0 0 0 1 0 1 1

1 1 M M M R R R

1 0 0 0 0 0 0 0

 

 

 

 

 

 

 

 

 

OPTIONAL EFFECTIVE ADDRESS EXTENSION

Instruction Fields:

ea=6-bit Effective Address=MMMRRR

Effective

 

 

 

 

 

 

Addressing Mode

M M M R R R

(Rn)-Nn

0

0

0

r

r

r

(Rn)+Nn

0

0

1

r

r

r

(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

Absolute address

1

1

0

0

0

0

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

Timing: 4+jx oscillator clock cycles

Memory: 1+ea program words

MOTOROLA

INSTRUCTION SET DETAILS

A - 137

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Motorola DSP56000, 24-Bit Digital Signal Processor manual Jsr