* Did mods as per Chris Dekker's RUNB
L4234    comb               Default to divide by 0 error
         ldb   #$2D
         tst   2,y          Is number to divide by 0?
         beq   L4233        Yes, return with error
         tst   8,y          Is dividend=0?
         lbeq  L40DD        Yes, answer=0, return from there
         lda   7,y          Get exponent of # to dividend
         suba  1,y          Subtract exponent of divisor
         lbvs  L40EF
         sta   7,y
         lda   #$21         ??? (count for exponent shifts?)
         ldb   5,y          Get sign byte of dividend
         eorb  $B,y         Calculate which sign result will be
         andb  #1           Just keep sign bit
         std   ,y           Save ??? & resulting sign
         ldq   2,y          Divide whole divisor mantissa by 2
         lsrd                /
         rorw               < these both eat sign bit and make mantissa a
         stq   2,y           \ 31 bit number
         ldq   8,y          Divide whole dividend by 2
         lsrd
         rorw
         clr   $B,y         Clear last byte of dividend mantissa
L426F    subw  4,y          Subtract divisor from dividend
         sbcd  2,y
         beq   L42AB
         bmi   L42A7
L427E    orcc  #1
L4280    dec   ,y
         beq   L42F8
         rol   $B,y
         rol   $A,y
         rol   9,y
         rol   8,y
         andcc #$fe
         rolw
         rold
         bcc   L426F
         addw  4,y
         adcd  2,y
         beq   L42AB
         bpl   L427E
L42A7    andcc #$FE
         bra   L4280

L42AB    tstw
         bne   L427E
         ldb   ,y
         decb  
         subb  #$10
         blt   L42CD
         subb  #$08
         blt   L42C2
         stb   ,y
         lda   $B,y
         ldb   #$80
         andcc #$fe
         bra   L42EB

L42C2    addb  #$08
         stb   ,y
         ldw   #$8000
         ldd   $A,y
         andcc #$fe
         bra   L42EB

L42CD    addb  #$08
         blt   L42DB
         stb   ,y
         ldq   9,y
         ldf   #$80
         andcc #$fe
         bra   L42EB

L42DB    addb  #$07
         stb   ,y
         ldq   8,y
         orcc  #$01
L42E5    rolw
         rold  
L42EB    dec   ,y
         bpl   L42E5
         tsta  
         bra   L42FC

L42F8    ldq   8,y
L42FC    bmi   L430C
         rolw
         rold
         dec   7,y
         lbvs  L40DD
L430C    addw  #1
         adcd  #0
         bcc   L4321
         rora  
         inc   7,y
         lbvs  L40DD
L4321    std   8,y
         tfr   w,d
         lsrb               Shift out sign bit
         lslb
         orb   1,y          Merge in result's sign
         std   $A,y
         inc   7,y
         lbvs  L40EF
L4331    leay  6,y          Eat temp var
         rts                & return

