PIC Microcontoller Program Flow ASCII Conversion Method

Convert ASCII to Upper Case

From http://www.myke.com/basic.htm

This is a practical application of conditional replacement. I think this subroutine demonstrates how the code works quite well.

ToUpper:
   addlw   255 - 'z'            ;  Get the High limit
   addlw   'z' - 'a' + 1        ;  Add Lower Limit to Set Carry
   btfss   STATUS, C            ;  If Carry Set, then Lower Case
    addlw  h'20'                ;   Carry NOT Set, Restore Character
   addlw   'A'                  ;  Add 'A' to restore the Character
   return

See:

• /techref/microchip/math/radix/b2a-7b3d-ba.htm Binary 7bit to ASCII decimal 3 digits by Bob Axtell James Newton replies: The table method shown in that code could be used to convert aSCII to upper case in fewer cycles, but it would be a much larger program.+

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