Scott Dattalo wrote:

>Tony Try this:
<snip>
>Since it's 12 instructions and uncommented it must be optimal :)

Well yes that works to :)

And here is Scotts code with comments:

;*******************************************************************
; CHECK_W_BCD_DIGIT_CLAMP - Checks if the value in w is bcd and that is
; if within the range <=3D MinBCD >=3D MaxBCD, if not bcd or outside =
range the value
; will be clamped to either MaxBCD or MinBCD.
; Input:=20
; W - The value to test/clamp
; MinBCD - Constant BCD,minimum accepted value, range 0x00-0x98 (must be =
less than MaxBCD)
; MaxBCD - Constant BCD,maximum accepted value, range 0x01-0x99 (must be =
higher than MinBCD)
; Temp - An temp file register in *current* bank or access ram
;=20
; Output:
; W - The clamped value of input (or Input if input is within range and =
BCD)=20
; Originator: Scott Dattalo
;=20
CHECK_W_BCD_DIGIT_CLAMP MACRO   MinBCD,MaxBCD,Temp
  local L1
        MOVWF   Temp    ; save input

        ADDLW   0x66    ; w =3D input+0x66 to test BCD conformity (i.e =
input<=3D 0x99)
        MOVLW   MaxBCD  ; w =3D MaxBCD
        SKPC            ; c  =3D input.h > 9
         SKPNDC         ; dc =3D input.l > 9
          bra   L1      ; exit with MaxBCD in w as input was not BCD

        CPFSGT  Temp    ; Compare input with MaxBCD
         MOVF   Temp,W  ; input <=3D MaxBCD, w =3D input

        MOVWF   Temp    ; Temp =3D input if input was <=3D MaxBCD=20
                                ; OR Temp =3D MaxBCD if input > MaxBCD

        MOVLW   MinBCD  ; w =3D MinBCD
        CPFSLT  Temp    ; compare input with MinBCD
         MOVF   Temp,W  ; input >=3D MinBCD, w =3D temp
         ; w =3D input if MinBCD<=3Dinput<=3DMaxBCD
         ; else if input>MaxBCD, w =3D MaxBCD
         ; else w =3D MinBCD    (input<MinBCD)
L1:
  ; w =3D MaxBCD
  endm

Thanks for playing :)
An handy macro for dealing with times/dates.=20

/Tony

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