usr/src/cmd/lisp/dmlad.s

        .globl  _dmlad
#
#       routine for destructive multiplication and additon to a bignum by
#       two fixnums.
#
#       from C, the invocation is dmlad(sdot,mul,add);
#       where sdot is the address of the first special cell of the bignum
#       mul is the multiplier, add is the fixnum to be added (The latter
#       being passed by value, as is the usual case.
#
#
#       Register assignments:
#
#       r11 = current sdot
#       r10 = carry
#       r9  = previous sdot, for relinking.
#
_dmlad: .word   0x0e00
        movl    4(ap),r11               #initialize cell pointer
        movl    12(ap),r10              #initialize carry
loop:   emul    8(ap),(r11),r10,r0      #r0 gets cell->car times mul + carry
#       ediv    $0x40000000,r0,r10,(r11)#cell->car gets prod % 2**30
#                                       #carry gets quotient
        extzv   $0,$30,r0,(r11)
        extv    $30,$32,r0,r10
        movl    r11,r9                  #save last cell for fixup at end.
        movl    4(r11),r11              #move to next cell
        bneq    loop                    #done indicated by 0 for next sdot
        tstl    r10                     #if carry zero no need to allocate
        beql    done                    #new bigit
        mcoml   r10,r3                  #test to see if neg 1.
        bneq    alloc                   #if not must allocate new cell.
        tstl    (r9)                    #make sure product isn't -2**30
        beql    alloc
        movl    r0,(r9)                 #save old lower half of product.
        brb     done
alloc:  calls   $0,_newsdot             #otherwise allocate new bigit
        movl    r10,(r0)                #store carry
        movl    r0,4(r9)                #save new link cell
done:   movl    4(ap),r0
        ret