Hmmm...

I was thinking about the problem of converting a byte into two character
bytes suitable for displaying them.  I was thinking that because '0' ASCII
is 0x030, I should be able to come up with a better routine.

This is what I came up with, it only uses six instructions for each
conversion (the other code I posted required 10 instructions) and no
intermediate temporary file register.  The only disadvantage I can see to
the code is that it will not work in a low-end device.

Does anybody see any problems with the routine below or a better way to do it?


myke



DispHex                         ;  Simplified Hex Output Subroutine
                                ;   Output the contents of "w" as two ASCII
                                ;   Bytes.

  movwf  Temp                   ;  Store the Value to be Displayed

  swapf  Temp, w                ;  Convert the High Nybble First
  andlw  0x00F
  addlw  '0' + 6                ;  Is it too Large for '0' to '9'?
  btfsc  STATUS, DC
   addlw 'A' - ( '0' + 10 )     ;  Yes, Make it "A" to "F"
  addlw  0 - 6                  ;  Convert Back to Valid Number
;  call  LCDCHAR

  movf   Temp, w                ;  Repeat for the Lower Nybble
  andlw  0x00F
  addlw  '0' + 6
  btfsc  STATUS, DC
   addlw 'A' - ( '0' + 10 )
  addlw  0 - 6
;  call  LCDCHAR

  return




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