Maxim Integrated Ultra-High-Speed Flash Microcontroller - Manual (Page 92)

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; THIS LOOP IS PERFORMED R5 TIMES, IN THIS EXAMPLE 64
MOVX A, @DPTR ; READ SOURCE DATA BYTE 3 +D
INC DPS ; CHANGE DPTR TO DESTINATION 4 +C
MOVX @DPTR, A ; WRITE DATA TO DESTINATION 3 +D
INC DPS ; CHANGE DATA POINTER TO SOURCE 4 +C
DJNZ R5, MOVE ; FINISHED WITH TABLE? 4
ANL DPS, #0EFH ; CLEAR AUTO-INC/DEC 3
PROGRAM 4: 64-BYTE BLOCK MOVE (DUAL DATA POINTER, TSL)
; SH and SL are high and low byte source address.
; DH and DL are high and low byte of destination address.
; DPS is the data pointer select. Reset condition DPTR0.
# UHSM CYCLES
DPS EQU 86h ; TELL ASSEMBLER ABOUT DPS
MOV R5, #64 ; NUMBER OF BYTES TO MOVE 2
ORL DPS, #20h ; SET TOGGLE SELECT (TSL) 3
MOV DPTR, #SHSL ; LOAD SOURCE ADDRESS 3
MOV DPTR, #DHDL ; LOAD DESTINATION ADDRESS 3
MOVE:
; THIS LOOP IS PERFORMED R5 TIMES, IN THIS EXAMPLE 64
MOVX A, @DPTR ; READ SOURCE DATA BYTE 3 +D
MOVX @DPTR, A ; WRITE DATA TO DESTINATION 4 +CD
INC DPTR ; NEXT SOURCE ADDRESS 2 +C
INC DPTR ; NEXT DESTINATION ADDRESS 1
DJNZ R5, MOVE ; FINISHED WITH TABLE? 4
ANL DPS, #0DFh ; CLEAR TOGGLE SELECT 3
PROGRAM 5: 64-BYTE BLOCK MOVE (DUAL DATA POINTER, AID, TSL)
; SH and SL are high and low byte source address.
; DH and DL are high and low byte of destination address.
; DPS is the data pointer select. Reset condition DPTR0.
# UHSM CYCLES
DPS EQU 86h ; TELL ASSEMBLER ABOUT DPS
MOV R5, #64 ; NUMBER OF BYTES TO MOVE 2
ORL DPS, #30h ; SET TOGGLE SELECT, AUTO-INC/DEC 3
MOV DPTR, #SHSL ; LOAD SOURCE ADDRESS 3
MOV DPTR, #DHDL ; LOAD DESTINATION ADDRESS 3
MOVE:
; THIS LOOP IS PERFORMED R5 TIMES, IN THIS EXAMPLE 64
MOVX A, @DPTR ; READ SOURCE DATA BYTE 3 +D
MOVX @DPTR, A ; WRITE DATA TO DESTINATION 4 +CD
DJNZ R5, MOVE ; FINISHED WITH TABLE? 5 +C
ANL DPS, #0CFh ; CLEAR TSL, AID 3
Note that since each pass through the loop saves additional clock cycles when compared to the single DPTR approach, efficiency
improvement when moving larger blocks is even greater using these features. Further speed improvement can be gained when exe-
cuting from internal flash program memory, since no code-fetch page misses (+C) would occur. For example, running Program 5 from
internal memory at 33MHz would require only 19.8µs (= 1/33MHz x (14 + 64 x 10)).
Ultra-High-Speed Flash
Microcontroller User’s Guide
Maxim Integrated