8-bit Divide

The following code divide two 8-bit integers (range 0...255) and outputs a 16-bit result using only real calculation, no lockup table so the size of the code is very small.

<source lang="6502tasm">

8-bit divide

by Bregalad

Enter with A = Dividend, Y=Divisor

Output with YA = (1/256)*(A/Y)

Division

       sta Dvd         ;Stores divident

sty Dvs ;Stores divisor lda #$00 sta Res ;Clear result

ldy #$10 ;The loop is for 16-bit result - asl Dvd rol A ;Shift divisor in 1 bit cmp Dvs ;Check if fractional dividend is greater than divisor bcc + sbc Dvs ;Substract (C is always set) + rol Res ;Shift result (1 if substation was done, 0 otherwise) rol Res2 dey bne - lda Res ldy Res2 rts </source>