// SPDX-License-Identifier: GPL-2.0
/*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see the file COPYING, or write
* to the Free Software Foundation, Inc.
*/
#include <linux/libgcc.h>
#define count_leading_zeros(COUNT, X) ((COUNT) = __builtin_clz(X))
#define W_TYPE_SIZE 32
#define __ll_B ((unsigned long) 1 << (W_TYPE_SIZE / 2))
#define __ll_lowpart(t) ((unsigned long) (t) & (__ll_B - 1))
#define __ll_highpart(t) ((unsigned long) (t) >> (W_TYPE_SIZE / 2))
/* If we still don't have umul_ppmm, define it using plain C. */
#if !defined(umul_ppmm)
#define umul_ppmm(w1, w0, u, v) \
do { \
unsigned long __x0, __x1, __x2, __x3; \
unsigned short __ul, __vl, __uh, __vh; \
\
__ul = __ll_lowpart(u); \
__uh = __ll_highpart(u); \
__vl = __ll_lowpart(v); \
__vh = __ll_highpart(v); \
\
__x0 = (unsigned long) __ul * __vl; \
__x1 = (unsigned long) __ul * __vh; \
__x2 = (unsigned long) __uh * __vl; \
__x3 = (unsigned long) __uh * __vh; \
\
__x1 += __ll_highpart(__x0); \
__x1 += __x2; \
if (__x1 < __x2) \
__x3 += __ll_B; \
\
(w1) = __x3 + __ll_highpart(__x1); \
(w0) = __ll_lowpart(__x1) * __ll_B + __ll_lowpart(__x0);\
} while (0)
#endif
#if !defined(sub_ddmmss)
#define sub_ddmmss(sh, sl, ah, al, bh, bl) \
do { \
unsigned long __x; \
__x = (al) - (bl); \
(sh) = (ah) - (bh) - (__x > (al)); \
(sl) = __x; \
} while (0)
#endif
/* Define this unconditionally, so it can be used for debugging. */
#define __udiv_qrnnd_c(q, r, n1, n0, d) \
do { \
unsigned long __d1, __d0, __q1, __q0; \
unsigned long __r1, __r0, __m; \
__d1 = __ll_highpart(d); \
__d0 = __ll_lowpart(d); \
\
__r1 = (n1) % __d1; \
__q1 = (n1) / __d1; \
__m = (unsigned long) __q1 * __d0; \
__r1 = __r1 * __ll_B | __ll_highpart(n0); \
if (__r1 < __m) { \
__q1--, __r1 += (d); \
if (__r1 >= (d)) \
if (__r1 < __m) \
__q1--, __r1 += (d); \
} \
__r1 -= __m; \
\
__r0 = __r1 % __d1; \
__q0 = __r1 / __d1; \
__m = (unsigned long) __q0 * __d0; \
__r0 = __r0 * __ll_B | __ll_lowpart(n0); \
if (__r0 < __m) { \
__q0--, __r0 += (d); \
if (__r0 >= (d)) \
if (__r0 < __m) \
__q0--, __r0 += (d); \
} \
__r0 -= __m; \
\
(q) = (unsigned long) __q1 * __ll_B | __q0; \
(r) = __r0; \
} while (0)
/* If udiv_qrnnd was not defined for this processor, use __udiv_qrnnd_c. */
#if !defined(udiv_qrnnd)
#define UDIV_NEEDS_NORMALIZATION 1
#define udiv_qrnnd __udiv_qrnnd_c
#endif
unsigned long long __udivmoddi4(unsigned long long u, unsigned long long v,
unsigned long long *rp)
{
const DWunion nn = {.ll = u };
const DWunion dd = {.ll = v };
DWunion rr, ww;
unsigned long d0, d1, n0, n1, n2;
unsigned long q0 = 0, q1 = 0;
unsigned long b, bm;
d0 = dd.s.low;
d1 = dd.s.high;
n0 = nn.s.low;
n1 = nn.s.high;
#if !UDIV_NEEDS_NORMALIZATION
if (d1 == 0) {
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)
/* Divide intentionally by zero. */
d0 = 1 / d0;
udiv_qrnnd(q1, n1, 0, n1, d0);
udiv_qrnnd(q0, n0, n1, n0, d0);
/* Remainder in n0. */
}
if (rp != 0) {
rr.s.low = n0;
rr.s.high = 0;
*rp = rr.ll;
}
#else /* UDIV_NEEDS_NORMALIZATION */
if (d1 == 0) {
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 >> (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)
/* Divide intentionally by zero. */
d0 = 1 / d0;
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) /\ (theleading quotient
* digit q1 = 1).
*
* This special case is necessary, not an
* optimization. (Shifts counts of W_TYPE_SIZE
* are undefined.)
*/
n1 -= d0;
q1 = 1;
} else {
/* Normalize. */
b = 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. */
}
if (rp != 0) {
rr.s.low = n0 >> bm;
rr.s.high = 0;
*rp = rr.ll;
}
#endif /* UDIV_NEEDS_NORMALIZATION */
} else {
if (d1 > n1) {
/* 00 = nn / DD */
q0 = 0;
q1 = 0;
/* Remainder in n1n0. */
if (rp != 0) {
rr.s.low = n0;
rr.s.high = n1;
*rp = rr.ll;
}
} 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;
if (rp != 0) {
rr.s.low = n0;
rr.s.high = n1;
*rp = rr.ll;
}
} else {
unsigned long m1, m0;
/* Normalize. */
b = 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. */
if (rp != 0) {
sub_ddmmss(n1, n0, n1, n0, m1, m0);
rr.s.low = (n1 << b) | (n0 >> bm);
rr.s.high = n1 >> bm;
*rp = rr.ll;
}
}
}
}
ww.s.low = q0;
ww.s.high = q1;
return ww.ll;
}
