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[SOL] Add SBF compiler-rt builtins
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‎compiler-rt/lib/builtins/sbf/udivmodti4.c‎

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//===-- udivmodti4.c - Implement __udivmodti4 -----------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements __udivmodti4 for the compiler_rt library.
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//
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//===----------------------------------------------------------------------===//
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#include "../int_lib.h"
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#ifdef CRT_HAS_128BIT
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// Effects: if rem != 0, *rem = a % b
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// Returns: a / b
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// Translated from Figure 3-40 of The PowerPC Compiler Writer's Guide
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COMPILER_RT_ABI tu_int __udivmodti4(tu_int a, tu_int b, tu_int *rem) {
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const unsigned n_udword_bits = sizeof(du_int) * CHAR_BIT;
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const unsigned n_utword_bits = sizeof(tu_int) * CHAR_BIT;
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utwords n;
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n.all = a;
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utwords d;
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d.all = b;
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utwords q;
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utwords r;
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unsigned sr;
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// special cases, X is unknown, K != 0
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if (n.s.high == 0) {
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if (d.s.high == 0) {
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// 0 X
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// ---
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// 0 X
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if (rem)
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*rem = n.s.low % d.s.low;
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return n.s.low / d.s.low;
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}
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// 0 X
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// ---
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// K X
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if (rem)
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*rem = n.s.low;
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return 0;
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}
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// n.s.high != 0
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if (d.s.low == 0) {
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if (d.s.high == 0) {
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// K X
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// ---
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// 0 0
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if (rem)
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*rem = n.s.high % d.s.low;
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return n.s.high / d.s.low;
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}
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// d.s.high != 0
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if (n.s.low == 0) {
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// K 0
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// ---
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// K 0
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if (rem) {
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r.s.high = n.s.high % d.s.high;
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r.s.low = 0;
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*rem = r.all;
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}
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return n.s.high / d.s.high;
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}
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// K K
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// ---
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// K 0
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if ((d.s.high & (d.s.high - 1)) == 0) /* if d is a power of 2 */ {
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if (rem) {
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r.s.low = n.s.low;
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r.s.high = n.s.high & (d.s.high - 1);
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*rem = r.all;
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}
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return n.s.high >> __builtin_ctzll(d.s.high);
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}
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// K K
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// ---
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// K 0
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sr = __builtin_clzll(d.s.high) - __builtin_clzll(n.s.high);
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// 0 <= sr <= n_udword_bits - 2 or sr large
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if (sr > n_udword_bits - 2) {
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if (rem)
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*rem = n.all;
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return 0;
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}
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++sr;
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// 1 <= sr <= n_udword_bits - 1
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// q.all = n.all << (n_utword_bits - sr);
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q.s.low = 0;
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q.s.high = n.s.low << (n_udword_bits - sr);
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// r.all = n.all >> sr;
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r.s.high = n.s.high >> sr;
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r.s.low = (n.s.high << (n_udword_bits - sr)) | (n.s.low >> sr);
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} else /* d.s.low != 0 */ {
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if (d.s.high == 0) {
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// K X
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// ---
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// 0 K
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if ((d.s.low & (d.s.low - 1)) == 0) /* if d is a power of 2 */ {
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if (rem)
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*rem = n.s.low & (d.s.low - 1);
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if (d.s.low == 1)
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return n.all;
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sr = __builtin_ctzll(d.s.low);
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q.s.high = n.s.high >> sr;
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q.s.low = (n.s.high << (n_udword_bits - sr)) | (n.s.low >> sr);
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return q.all;
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}
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// K X
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// ---
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// 0 K
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sr = 1 + n_udword_bits + __builtin_clzll(d.s.low) -
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__builtin_clzll(n.s.high);
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// 2 <= sr <= n_utword_bits - 1
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// q.all = n.all << (n_utword_bits - sr);
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// r.all = n.all >> sr;
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if (sr == n_udword_bits) {
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q.s.low = 0;
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q.s.high = n.s.low;
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r.s.high = 0;
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r.s.low = n.s.high;
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} else if (sr < n_udword_bits) /* 2 <= sr <= n_udword_bits - 1 */ {
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q.s.low = 0;
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q.s.high = n.s.low << (n_udword_bits - sr);
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r.s.high = n.s.high >> sr;
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r.s.low = (n.s.high << (n_udword_bits - sr)) | (n.s.low >> sr);
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} else /* n_udword_bits + 1 <= sr <= n_utword_bits - 1 */ {
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q.s.low = n.s.low << (n_utword_bits - sr);
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q.s.high = (n.s.high << (n_utword_bits - sr)) |
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(n.s.low >> (sr - n_udword_bits));
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r.s.high = 0;
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r.s.low = n.s.high >> (sr - n_udword_bits);
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}
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} else {
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// K X
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// ---
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// K K
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sr = __builtin_clzll(d.s.high) - __builtin_clzll(n.s.high);
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// 0 <= sr <= n_udword_bits - 1 or sr large
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if (sr > n_udword_bits - 1) {
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if (rem)
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*rem = n.all;
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return 0;
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}
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++sr;
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// 1 <= sr <= n_udword_bits
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// q.all = n.all << (n_utword_bits - sr);
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// r.all = n.all >> sr;
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q.s.low = 0;
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if (sr == n_udword_bits) {
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q.s.high = n.s.low;
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r.s.high = 0;
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r.s.low = n.s.high;
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} else {
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r.s.high = n.s.high >> sr;
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r.s.low = (n.s.high << (n_udword_bits - sr)) | (n.s.low >> sr);
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q.s.high = n.s.low << (n_udword_bits - sr);
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}
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}
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}
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// Not a special case
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// q and r are initialized with:
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// q.all = n.all << (n_utword_bits - sr);
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// r.all = n.all >> sr;
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// 1 <= sr <= n_utword_bits - 1
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su_int carry = 0;
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for (; sr > 0; --sr) {
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// r:q = ((r:q) << 1) | carry
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r.s.high = (r.s.high << 1) | (r.s.low >> (n_udword_bits - 1));
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r.s.low = (r.s.low << 1) | (q.s.high >> (n_udword_bits - 1));
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q.s.high = (q.s.high << 1) | (q.s.low >> (n_udword_bits - 1));
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q.s.low = (q.s.low << 1) | carry;
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// carry = 0;
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// if (r.all >= d.all)
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// {
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// r.all -= d.all;
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// carry = 1;
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// }
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const ti_int s = (ti_int)(d.all - r.all - 1) >> (n_utword_bits - 1);
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carry = s & 1;
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r.all -= d.all & s;
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}
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q.all = (q.all << 1) | carry;
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if (rem)
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*rem = r.all;
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return q.all;
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}
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#endif // CRT_HAS_128BIT

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