ADDRESSING

EXAMPLE: MOVE A1,X: (R0)

 

 

 

 

BEFORE EXECUTION

 

 

 

 

 

 

 

 

 

 

 

A2

 

A1

 

 

 

A0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

55

48

47

24

23

 

0

 

 

 

 

 

 

 

 

 

 

0

1

2 3 4 5 6 7

8

9 A B C D

 

7

0

23

0

23

 

0

 

 

 

 

 

 

 

X MEMORY

 

 

 

 

 

23

 

0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

$1000 X X X X X X

150

R0

$1000

150

N0

XXXX

150

M0

$FFFF

Assembler Syntax: (Rn)

Memory Spaces: P:, X:, Y:, XY:, L:

Additional Instruction Execution Time (Clocks): 0

Additional Effective Address Words: 0

 

 

 

 

 

AFTER EXECUTION

 

 

 

 

 

 

 

 

 

 

 

 

 

A2

A1

 

 

 

A0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

55

48 47

24

23

 

0

 

 

 

 

 

 

 

 

 

 

 

 

0

1

2

3 4 5 6 7

8

9 A B C D

7

0 23

0

23

 

0

 

 

 

 

 

 

 

 

X MEMORY

 

 

 

 

 

 

23

 

0

$1000 $ 2 3 4 5 6 7

150

R0

$1000

150

N0

XXXX

150

M0

$FFFF

Figure 4-4 Address Register Indirect — No Update

modifying the contents of Rn without an associated data move.

4.4.1.4Postincrement By Offset Nn

The address of the operand is in the address register, Rn (see Table 4-1and Figure 4-7). After the operand address is used, it is incremented by the contents of the Nn register and stored in the same address register. The contents of the Nn register are unchanged. This mode can be used for making XY: memory references and for modifying the contents of

4 - 10

ADDRESS GENERATION UNIT

MOTOROLA

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Image 63
Motorola 24-Bit Digital Signal Processor, DSP56000 manual Address Register Indirect No Update, Postincrement By Offset Nn