
INSTRUCTION SET
S3C8248/C8245/P8245/C8247/C8249/P8249
6-56
LDCPD/LDEPD
—
Load Memory with Pre-Decrement
LDCPD/
LDEPD
dst,src
Operation:
rr
←
rr – 1
dst
←
src
These instructions are used for block transfers of data from program or data memory from the
register file. The address of the memory location is specified by a working register pair and is
first decremented. The contents of the source location are then loaded into the destination
location. The contents of the source are unaffected.
LDCPD refers to program memory and LDEPD refers to external data memory. The assembler
makes 'Irr' an even number for program memory and an odd number for external data memory.
Flags:
No flags are affected.
Format:
Bytes
Cycles
Opcode
(Hex)
Addr Mode
dst src
opc
src | dst
2
14
F2
Irr
r
Examples:
Given: R0 = 77H, R6 = 30H, and R7 = 00H:
LDCPD
@RR6,R0
; (RR6
←
RR6 – 1)
; 77H (contents of R0) is loaded into program memory location
; 2FFFH (3000H – 1H)
; R0 = 77H, R6 = 2FH, R7 = 0FFH
LDEPD
@RR6,R0
; (RR6
←
RR6 – 1)
; 77H (contents of R0) is loaded into external data memory
; location 2FFFH (3000H – 1H)
; R0 = 77H, R6 = 2FH, R7 = 0FFH
Summary of Contents for C8245
Page 31: ...ADDRESS SPACES S3C8248 C8245 P8245 C8247 C8249 P8249 2 20 NOTES ...
Page 107: ...INTERRUPT STRUCTURE S3C8248 C8245 P8245 C8247 C8249 P8249 5 18 NOTES ...
Page 195: ...INSTRUCTION SET S3C8248 C8245 P8245 C8247 C8249 P8249 6 88 NOTES ...
Page 221: ...I O PORTS S3C8248 C8245 P8245 C8247 C8249 P8249 9 16 NOTES ...
Page 245: ...16 BIT TIMER 0 1 S3C8248 C8245 P8245 C8247 C8249 P8249 12 10 NOTES ...
Page 249: ...WATCH TIMER S3C8248 C8245 P8245 C8247 C8249 P8249 13 4 NOTES ...
Page 267: ...A D CONVERTER S3C8248 C8245 P8245 C8247 C8249 P8249 15 6 NOTES ...
Page 299: ...S3P8245 P8249 OTP S3C8248 C8245 P8245 C8247 C8249 P8249 21 8 NOTES ...
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