Indirect Working Register Addressing To Program Or Data Memory - Samsung S3C80A5B User Manual

ADDRESSING MODES
INDIRECT REGISTER ADDRESSING MODE (Continued)
4-bit Working
Register Address
Example Instruction
References either
Program Memory or
Data Memory
NOTE: LDE command is not available, because an external interface is not implemented for
Figure 3-6. Indirect Working Register Addressing to Program or Data Memory
3-6
Program Memory
dst src
OPCODE
Sample Instructions:
LDC R5,@RR6
LDE R3,@RR14
LDE @RR4, R8
the S3C80A5B
MSB Points to
RP0 or RP1
Next 2-bit Point
to Working Register
Pair
(1 of 4)
LSB Selects
Value used in
Instruction
; Program memory access
; External data memory access
; External data memory access
Register File
RP0 or RP1
Register
Pair
Program Memory
or
Data Memory
OPERAND
S3C80A5B
Selected
RP Points
to Start of
Working
Register
Block
16-Bit
Address
Points to
Program
Memory or
Data
Memory