name : '__attribute__((__noreturn__))')
pre_args += '-DHAVE_FUNC_ATTRIBUTE_NORETURN'
endif
+if cc.compiles('__uint128_t foo(void) { return 0; }',
+ name : '__uint128_t')
+ pre_args += '-DHAVE_UINT128'
+endif
# TODO: this is very incomplete
if ['linux', 'cygwin', 'gnu'].contains(host_machine.system())
--- /dev/null
+/*
+ * Copyright © 2010 Valve Software
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include <stdint.h>
+
+/*
+ * Code for fast 32-bit unsigned remainder, based off of "Faster Remainder by
+ * Direct Computation: Applications to Compilers and Software Libraries,"
+ * available at https://arxiv.org/pdf/1902.01961.pdf.
+ *
+ * util_fast_urem32(n, d, REMAINDER_MAGIC(d)) returns the same thing as
+ * n % d for any unsigned n and d, however it compiles down to only a few
+ * multiplications, so it should be faster than plain uint32_t modulo if the
+ * same divisor is used many times.
+ */
+
+#define REMAINDER_MAGIC(divisor) \
+ ((uint64_t) ~0ull / (divisor) + 1)
+
+/*
+ * Get bits 64-96 of a 32x64-bit multiply. If __int128_t is available, we use
+ * it, which usually compiles down to one instruction on 64-bit architectures.
+ * Otherwise on 32-bit architectures we usually get four instructions (one
+ * 32x32->64 multiply, one 32x32->32 multiply, and one 64-bit add).
+ */
+
+static inline uint32_t
+_mul32by64_hi(uint32_t a, uint64_t b)
+{
+#ifdef HAVE_UINT128
+ return ((__uint128_t) b * a) >> 64;
+#else
+ /*
+ * Let b = b0 + 2^32 * b1. Then a * b = a * b0 + 2^32 * a * b1. We would
+ * have to do a 96-bit addition to get the full result, except that only
+ * one term has non-zero lower 32 bits, which means that to get the high 32
+ * bits, we only have to add the high 64 bits of each term. Unfortunately,
+ * we have to do the 64-bit addition in case the low 32 bits overflow.
+ */
+ uint32_t b0 = (uint32_t) b;
+ uint32_t b1 = b >> 32;
+ return ((((uint64_t) a * b0) >> 32) + (uint64_t) a * b1) >> 32;
+#endif
+}
+
+static inline uint32_t
+util_fast_urem32(uint32_t n, uint32_t d, uint64_t magic)
+{
+ uint64_t lowbits = magic * n;
+ uint32_t result = _mul32by64_hi(d, lowbits);
+ assert(result == n % d);
+ return result;
+}
+
)
subdir('tests/fast_idiv_by_const')
+ subdir('tests/fast_urem_by_const')
subdir('tests/hash_table')
subdir('tests/string_buffer')
subdir('tests/vma')
--- /dev/null
+/*
+ * Copyright © 2018 Intel Corporation
+ * Copyright © 2019 Valve Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#undef NDEBUG
+
+#include <gtest/gtest.h>
+#include "util/fast_urem_by_const.h"
+
+#define RAND_TEST_ITERATIONS 100000
+
+static uint32_t
+rand_uint(unsigned min)
+{
+ /* Make sure we get some small and large numbers and powers of two every
+ * once in a while
+ */
+ int k = rand() % 64;
+ if (k == 17) {
+ return min + (rand() % 16);
+ } else if (k == 42) {
+ return UINT32_MAX - (rand() % 16);
+ } else if (k == 9) {
+ uint32_t r;
+ do {
+ r = 1ull << (rand() % 32);
+ } while (r < min);
+ return r;
+ }
+
+ if (min == 0) {
+ uint32_t r = 0;
+ for (unsigned i = 0; i < 4; i++)
+ r |= ((uint32_t)rand() & 0xf) << i * 8;
+ return r >> (31 - (rand() % 32));
+ } else {
+ uint64_t r;
+ do {
+ r = rand_uint(0);
+ } while (r < min);
+ return r;
+ }
+}
+
+static void
+test_case(uint32_t n, uint32_t d)
+{
+ assert(d >= 1);
+ uint64_t magic = REMAINDER_MAGIC(d);
+ /* Note: there's already an assert inside util_fast_urem32(), so the
+ * EXPECT_EQ is only here to make sure the test fails with a wrong result
+ * even if asserts are disabled. Ideally we could disable the assert just
+ * for the test to get a better error message, but that doesn't seem too
+ * easy.
+ */
+ EXPECT_EQ(util_fast_urem32(n, d, magic), n % d);
+}
+
+TEST(fast_urem_by_const, random)
+{
+ for (unsigned i = 0; i < RAND_TEST_ITERATIONS; i++) {
+ uint64_t n = rand_uint(0);
+ uint64_t d = rand_uint(1);
+ test_case(n, d);
+ }
+}
+
+TEST(fast_urem_by_const, special_cases)
+{
+ test_case(0, 1);
+ test_case(0, UINT32_MAX);
+ test_case(UINT32_MAX, 1);
+ test_case(1, UINT32_MAX);
+ test_case(UINT32_MAX, UINT32_MAX);
+ test_case(UINT32_MAX, UINT32_MAX - 1);
+ test_case(UINT32_MAX - 1, UINT32_MAX - 1);
+ test_case(UINT32_MAX - 2, UINT32_MAX - 1);
+}
+
--- /dev/null
+# Copyright © 2018 Intel Corporation
+# Copyright © 2010 Valve Corporation
+
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
+
+test(
+ 'fast_urem_by_const',
+ executable(
+ 'fast_urem_by_const_test',
+ 'fast_urem_by_const_test.cpp',
+ dependencies : [dep_thread, dep_dl, idep_gtest],
+ include_directories : inc_common,
+ link_with : [libmesa_util],
+ ),
+ suite : ['util'],
+)
projects / mesa.git / commitdiff