udivmodti4.c
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/* This has so very few changes over libgcc2's __udivmoddi4 it isn't funny. */
#include <math-emu/soft-fp.h>
#undef count_leading_zeros
#define count_leading_zeros __FP_CLZ
void
_fp_udivmodti4(_FP_W_TYPE q[2], _FP_W_TYPE r[2],
_FP_W_TYPE n1, _FP_W_TYPE n0,
_FP_W_TYPE d1, _FP_W_TYPE d0)
{
_FP_W_TYPE q0, q1, r0, r1;
_FP_I_TYPE b, bm;
if (d1 == 0)
{
#if !UDIV_NEEDS_NORMALIZATION
if (d0 > n1)
{
/* 0q = nn / 0D */
udiv_qrnnd (q0, n0, n1, n0, d0);
q1 = 0;
/* Remainder in n0. */
}
else
{
/* qq = NN / 0d */
if (d0 == 0)
d0 = 1 / d0; /* Divide intentionally by zero. */
udiv_qrnnd (q1, n1, 0, n1, d0);
udiv_qrnnd (q0, n0, n1, n0, d0);
/* Remainder in n0. */
}
r0 = n0;
r1 = 0;
#else /* UDIV_NEEDS_NORMALIZATION */
if (d0 > n1)
{
/* 0q = nn / 0D */
count_leading_zeros (bm, d0);
if (bm != 0)
{
/* Normalize, i.e. make the most significant bit of the
denominator set. */
d0 = d0 << bm;
n1 = (n1 << bm) | (n0 >> (_FP_W_TYPE_SIZE - bm));
n0 = n0 << bm;
}
udiv_qrnnd (q0, n0, n1, n0, d0);
q1 = 0;
/* Remainder in n0 >> bm. */
}
else
{
/* qq = NN / 0d */
if (d0 == 0)
d0 = 1 / d0; /* Divide intentionally by zero. */
count_leading_zeros (bm, d0);
if (bm == 0)
{
/* From (n1 >= d0) /\ (the most significant bit of d0 is set),
conclude (the most significant bit of n1 is set) /\ (the
leading quotient digit q1 = 1).
This special case is necessary, not an optimization.
(Shifts counts of SI_TYPE_SIZE are undefined.) */
n1 -= d0;
q1 = 1;
}
else
{
_FP_W_TYPE n2;
/* Normalize. */
b = _FP_W_TYPE_SIZE - bm;
d0 = d0 << bm;
n2 = n1 >> b;
n1 = (n1 << bm) | (n0 >> b);
n0 = n0 << bm;
udiv_qrnnd (q1, n1, n2, n1, d0);
}
/* n1 != d0... */
udiv_qrnnd (q0, n0, n1, n0, d0);
/* Remainder in n0 >> bm. */
}
r0 = n0 >> bm;
r1 = 0;
#endif /* UDIV_NEEDS_NORMALIZATION */
}
else
{
if (d1 > n1)
{
/* 00 = nn / DD */
q0 = 0;
q1 = 0;
/* Remainder in n1n0. */
r0 = n0;
r1 = n1;
}
else
{
/* 0q = NN / dd */
count_leading_zeros (bm, d1);
if (bm == 0)
{
/* From (n1 >= d1) /\ (the most significant bit of d1 is set),
conclude (the most significant bit of n1 is set) /\ (the
quotient digit q0 = 0 or 1).
This special case is necessary, not an optimization. */
/* The condition on the next line takes advantage of that
n1 >= d1 (true due to program flow). */
if (n1 > d1 || n0 >= d0)
{
q0 = 1;
sub_ddmmss (n1, n0, n1, n0, d1, d0);
}
else
q0 = 0;
q1 = 0;
r0 = n0;
r1 = n1;
}
else
{
_FP_W_TYPE m1, m0, n2;
/* Normalize. */
b = _FP_W_TYPE_SIZE - bm;
d1 = (d1 << bm) | (d0 >> b);
d0 = d0 << bm;
n2 = n1 >> b;
n1 = (n1 << bm) | (n0 >> b);
n0 = n0 << bm;
udiv_qrnnd (q0, n1, n2, n1, d1);
umul_ppmm (m1, m0, q0, d0);
if (m1 > n1 || (m1 == n1 && m0 > n0))
{
q0--;
sub_ddmmss (m1, m0, m1, m0, d1, d0);
}
q1 = 0;
/* Remainder in (n1n0 - m1m0) >> bm. */
sub_ddmmss (n1, n0, n1, n0, m1, m0);
r0 = (n1 << b) | (n0 >> bm);
r1 = n1 >> bm;
}
}
}
q[0] = q0; q[1] = q1;
r[0] = r0, r[1] = r1;
}