# S/390 __udiv_qrnnd# r2 : &__r# r3 : upper half of 64 bit word n# r4 : lower half of 64 bit word n# r5 : divisor d# the reminder r of the division is to be stored to &__r and# the quotient q is to be returned        .text        .globl __udiv_qrnnd__udiv_qrnnd:        st    %r2,24(%r15)        # store pointer to reminder for later        lr    %r0,%r3             # reload n	lr    %r1,%r4	ltr   %r2,%r5             # reload and test divisor        jp    5f        # divisor >= 0x80000000	srdl  %r0,2               # n/4        srl   %r2,1               # d/2        slr   %r1,%r2             # special case if last bit of d is set        brc   3,0f                #  (n/4) div (n/2) can overflow by 1        ahi   %r0,-1              #  trick: subtract n/2, then divide0:      dr    %r0,%r2             # signed division        ahi   %r1,1               #  trick part 2: add 1 to the quotient        # now (n >> 2) = (d >> 1) * %r1 + %r0	lhi   %r3,1        nr    %r3,%r1             # test last bit of q        jz    1f        alr   %r0,%r2             # add (d>>1) to r1:      srl   %r1,1               # q >>= 1        # now (n >> 2) = (d&-2) * %r1 + %r0        lhi   %r3,1        nr    %r3,%r5             # test last bit of d        jz    2f        slr   %r0,%r1             # r -= q	brc   3,2f                # borrow ?	alr   %r0,%r5             # r += d	ahi   %r1,-12:      # now (n >> 2) = d * %r1 + %r0        alr   %r1,%r1             # q <<= 1        alr   %r0,%r0             # r <<= 1        brc   12,3f               # overflow on r ?        slr   %r0,%r5             # r -= d        ahi   %r1,1               # q += 13:      lhi   %r3,2        nr    %r3,%r4             # test next to last bit of n        jz    4f        ahi   %r0,1               # r += 14:      clr   %r0,%r5             # r >= d ?        jl    6f        slr   %r0,%r5             # r -= d        ahi   %r1,1               # q += 1        # now (n >> 1) = d * %r1 + %r0        j     6f5:      # divisor < 0x80000000	srdl  %r0,1        dr    %r0,%r2             # signed division        # now (n >> 1) = d * %r1 + %r06:      alr   %r1,%r1             # q <<= 1        alr   %r0,%r0             # r <<= 1        brc   12,7f               # overflow on r ?        slr   %r0,%r5             # r -= d        ahi   %r1,1               # q += 17:      lhi   %r3,1        nr    %r3,%r4             # isolate last bit of n        alr   %r0,%r3             # r += (n & 1)        clr   %r0,%r5             # r >= d ?        jl    8f        slr   %r0,%r5             # r -= d        ahi   %r1,1               # q += 18:      # now n = d * %r1 + %r0	l     %r2,24(%r15)        st    %r0,0(%r2)        lr    %r2,%r1        br    %r14	.end	__udiv_qrnnd