AMD Am186 Series, Instruction Set

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Instruction Set 4-249
XLAT XLAT
Examples
This example translates a string of ASCII numbers in memory to unpacked decimal digits.
The microcontroller translates the numbers, one by one, from first to last.
This example translates the offset (base+index) of a byte within a table in memory to the
value of that byte.
; defined in SEG_D segment
TABLE DB 0,1,2,3,4,5,6,7,8,9
STRING DB ”0123456789”
; notify assembler: DS and ES specify the
; same segment of memory
ASSUME DS:SEG_D, ES:SEG_D
; set up DS and ES with the same segment address
MOV AX,SEG_D ; load segment into DS and ES
MOV DS,AX ; DS points to SEG_D
MOV ES,AX ; ES points to SEG_D
; translate ASCII numbers to unpacked decimal digits
; set up for string operation
LEA SI,STRING ; load source offset (segment = DS)
LEA DI,STRING ; load dest. offset (segment = DS)
MOV CX,10 ; set up counter
CLD ; process string from low to high
LEA BX,TABLE ; load table base (segment = DS)
ASCII2BCD:
; translate bytes
LODSB ; copy ASCII # from string to AL
XLATB ; translate to unpacked decimal
STOSB ; copy back to string
LOOP ASCII2BCD ; while CX is not 0, jump
; to top of loop
; defined in SEG_B segment
TABLE DB 3,6,12,24,48,96,192
; notify assembler: DS and ES point to
; different segments of memory
ASSUME DS:SEG_A, ES:SEG_B
; set up DS and ES with different segment addresses
MOV AX,SEG_A ; load one segment into DS
MOV DS,AX ; DS points to SEG_A
MOV AX,SEG_B ; load another segment into ES
MOV ES,AX ; ES points to SEG_B
; translate index to component (override default segment)
MOV AL,3 ; set up index: AL = 3
LEA BX,ES:TABLE ; load table base into BX
XLAT ES:[BX] ; translate: AL = 24