Texas Instruments TMS320C3x User Manual

Page 166

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Indirect Addressing

6-13

Addressing Modes

Example 6–11. Indirect Addressing With Preindex Add

The address of the operand to fetch is the sum of an auxiliary register (AR

n)

and an index register (IR0 or IR1).

Operation:

operand address = AR

n + IRm

Assembler Syntax:

*+ AR

n(IRm)

Modification Field:

01000

if

m = 0

10000

if

m = 1

(+)

0

0

31

24 23

Address

x

x

AR

n

31

IR

m

x

0

31

Index

Operand

x

24 23

Example 6–12. Indirect Addressing With Preindex Subtract

The address of the operand to fetch is the difference of an auxiliary register
(AR

n) and an index register (IR0 or IR1).

Operation:

operand address = AR

n – IRm

Assembler Syntax:

*– AR

n(IRm)

Modification Field:

01001

if

m = 0

10001

if

m = 1

(–)

0

0

31

24 23

Address

x

x

AR

n

31

IR

m

x

0

31

Index

Operand

x

24

23

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