Print Page - Convert Lowercase string to Uppercase string

Title: Convert Lowercase string to Uppercase string
Post by: josefalarka on January 12, 2011, 12:54:53 AM

The code below is to convert uppercase string to lowercase string from the book of Peter Abel (IBM PC Assembly Language Programming). How to translate this code to convert lowercase to uppercase.

TITLE   A07CASE (COM)    Change uppercase to lowercase
   .MODEL   SMALL
   .CODE
   ORG   100H
BEGIN:   JMP   A10MAIN
; --------------------------------------------------
CONAME   DB   'THIS STRING WILL BE CONVERTED TO UPPERCASE', '$'
; --------------------------------------------------

A10MAIN   PROC   NEAR
   LEA   BX,CONAME+1   ;1st char to change
   MOV   CX,15      ;No. of chars to change
A20:
   MOV   AH,[BX]      ;Character from CONAME
   CMP   AH,41H      ;Is it
   JB   A30      ; an upper
   CMP   AH,5AH      ; case
   JA   A30      ; letter?
   XOR   AH,00100000B   ;Yes, convert
   MOV   [BX],AH      ;Restore in CONAME
A30:
   INC   BX      ;Set for next char
   LOOP   A20      ;Loop 15 times            ;Done,

   MOV   AH,09H      ; display
   LEA   DX,CONAME   ; CONAME
   INT   21H
   MOV   AX,4C00H   ;End processing
   INT   21HA
A10MAIN   ENDP
END BEGIN

Title: Re: Convert Lowercase string to Uppercase string
Post by: dedndave on January 12, 2011, 01:42:54 AM

first of all - this is 16-bit code
not sure if you are aware of it - we have a 16-bit subforum (near bottom of main page)
also - it is ORG'ed at 100h - presumably to make a .COM program - in which case, the model should be .TINY

Code Select

BEGIN:   JMP   A10MAIN
; --------------------------------------------------
CONAME   DB   'this string will be converted to uppercase', '$'
; --------------------------------------------------

A10MAIN   PROC   NEAR   
   LEA   BX,CONAME+1   ;1st char to change   
   MOV   CX,15      ;No. of chars to change
A20:   
   MOV   AH,[BX]      ;Character from CONAME   
   CMP   AH,61H      ;Is it       was 41h('A') - 61h = 'a'
   JB   A30      ;  a lower   
   CMP   AH,7AH      ;  case      was 5Ah('Z') - 7Ah = 'z'
   JA   A30      ;  letter?   
   XOR   AH,00100000B   ;Yes, convert   
   MOV   [BX],AH      ;Restore in CONAME
A30:   
   INC   BX      ;Set for next char   
   LOOP   A20      ;Loop 15 times            ;Done,   

   MOV   AH,09H      ;  display   
   LEA   DX,CONAME   ;  CONAME   
   INT   21H   
   MOV   AX,4C00H   ;End processing   
   INT   21HA
A10MAIN   ENDP
            END     BEGIN

Title: Re: Convert Lowercase string to Uppercase string
Post by: josefalarka on January 13, 2011, 03:05:20 AM

Thanks for you help. I got it. This code is a 16 bit dos programming. I use A86 as my assembler, now I started to learn. Thanks.

Title: Re: Convert Lowercase string to Uppercase string
Post by: dedndave on January 13, 2011, 04:01:54 AM

QuoteI use A86 as my assembler, now I started to learn

ouch !
in the upper right-hand corner of the forum are several links
download the masm32 package - it's free :U

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Miscellaneous Forums => 16 bit DOS Programming => Topic started by: josefalarka on January 12, 2011, 12:54:53 AM