; pbdiv.psm

; original by Peter Smith

; imported to pBlazIDE and corrected



; divider function, 8 by 8

; data independent



divisor             EQU       s1

dividend            EQU       s2

rem                 EQU       s3

temp                EQU       s4

count               EQU       s5



; assumes divisor is in divisor

; dividend in dividend

; returns quotient in dividend (original value overwritten)

; returns remainder in rem

; 

div8:               LOAD      count, 8            ; loop count

                    LOAD      rem, 0

                    SL0       dividend            ; init for test

                    SLA       rem                 ; get bit from dividend thru carry



divlp0:             SUB       rem, divisor        ; do subtraction

                    JUMP      C, cantsub          ; <0, add back

                    LOAD      temp, 1             ; otherwise, we'll push a 1 into the result

                    JUMP      lptest              ; go to loop test

cantsub:            ADD       rem, divisor        ; add it back

                    LOAD      temp, 0             ; and set a zero for result bit

lptest:             SR0       temp

                    SLA       dividend            ; put new bit in result

                    SLA       rem                 ; get bit from dividend thru carry

                    SUB       count, 1            ; 8 done?

                    JUMP      NZ, divlp0



                    RET                           ; yes