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INSTRUCTION SET
S3P80C5/C80C5/C80C8
6-54
LDCD/LDED
—
Load Memory and Decrement
LDCD/LDED
dst,src
Operation:
dst
←
src
rr
←
rr – 1
These instructions are used for user stacks or block transfers of data from program or data
memory to the register file. The address of the memory location is specified by a working register
pair. The contents of the source location are loaded into the destination location. The memory
address is then decremented. The contents of the source are unaffected.
LDCD references program memory and LDED references external data memory. The assembler
makes 'Irr' an even number for program memory and an odd number for data memory.
Flags:
No flags are affected.
Format:
Bytes
Cycles
Opcode
(Hex)
Addr Mode
dst src
opc
dst | src
2
10
E2
r
Irr
Examples:
Given: R6 = 10H, R7 = 33H, R8 = 12H, program memory location 1033H = 0CDH, and
external data memory location 1033H = 0DDH:
LDCD
R8,@RR6
; 0CDH (contents of program memory location 1033H) is loaded
; into R8 and RR6 is decremented by one
; R8 = 0CDH, R6 = 10H, R7 = 32H (RR6
←
RR6 – 1)
LDED
R8,@RR6
; 0DDH (contents of data memory location 1033H) is loaded
; into R8 and RR6 is decremented by one (RR6
←
RR6 – 1)
; R8 = 0DDH, R6 = 10H, R7 = 32H
Summary of Contents for S3P80C5
Page 2: ...S3P80C5 C80C5 C80C8 8 BIT CMOS MICROCONTROLLERS USER S MANUAL Revision 1 ...
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Page 49: ...ADDRESS SPACES S3P80C5 C80C5 C80C8 2 20 NOTES ...
Page 197: ...INSTRUCTION SET S3P80C5 C80C5 C80C8 6 88 NOTES ...
Page 201: ...CLOCK CIRCUITS S3P80C5 C80C5 C80C8 7 4 NOTES ...
Page 237: ...TIMER 1 S3P80C5 C80C5 C80C8 11 6 NOTES ...
Page 245: ...COUNTER A S3P80C5 C80C5 C80C8 12 8 NOTES ...
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