ADDRESSING MODES

S3C9228/P9228

 

 

INDEXED ADDRESSING MODE (Continued)

4-Bit Working Register Address

Program Memory

XS (OFFSET)

dst

src

 

 

OPCODE

NEXT 3 Bits

Point to Working

Register Pair

(1 of 8)

LSB Selects

Register File

Register

Pair

16-Bit address added to offset

+

8-Bits 16-Bits

16-Bits

Program Memory

or

Data Memory

OPERAND

Value used in Instruction

Sample Instructions:

 

 

LDC

R4, #04H[RR2]

;

The values in the program address (RR2 + #04H)

 

 

 

are loaded into register R4.

LDE

R4,#04H[RR2]

;

Identical operation to LDC example, except that

 

 

 

external program memory is accessed.

Figure 3-8. Indexed Addressing to Program or Data Memory with Short Offset

3-8

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Image 48
Samsung S3C9228/P9228, 8-Bit CMOS Microcontroller user manual Indexed Addressing Mode