From 0dca6730b420f940794a51e8342f6c331934608f Mon Sep 17 00:00:00 2001 From: Jason Ekstrand Date: Fri, 29 Dec 2017 13:30:32 -0800 Subject: [PATCH] util: Add a simple big math library Reviewed-by: Ian Romanick --- src/util/Makefile.am | 1 + src/util/Makefile.sources | 1 + src/util/bigmath.h | 112 ++++++++++++++++++++++++++++++++++++++ src/util/meson.build | 1 + 4 files changed, 115 insertions(+) create mode 100644 src/util/bigmath.h diff --git a/src/util/Makefile.am b/src/util/Makefile.am index efb94caff71..d79f2b320be 100644 --- a/src/util/Makefile.am +++ b/src/util/Makefile.am @@ -21,6 +21,7 @@ SUBDIRS = . \ xmlpool \ + tests/fast_idiv_by_const \ tests/hash_table \ tests/string_buffer \ tests/set diff --git a/src/util/Makefile.sources b/src/util/Makefile.sources index b562d6cd6f4..5b1548c733c 100644 --- a/src/util/Makefile.sources +++ b/src/util/Makefile.sources @@ -1,4 +1,5 @@ MESA_UTIL_FILES := \ + bigmath.h \ bitscan.c \ bitscan.h \ bitset.h \ diff --git a/src/util/bigmath.h b/src/util/bigmath.h new file mode 100644 index 00000000000..6339bb6f6ca --- /dev/null +++ b/src/util/bigmath.h @@ -0,0 +1,112 @@ +/* + * Copyright © 2018 Intel 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. + */ + +#ifndef UTIL_BIGMATH_H +#define UTIL_BIGMATH_H + +#include "macros.h" + +#include +#include +#include + +static inline bool +_ubm_add_u32arr(uint32_t *dst, unsigned dst_len, + uint32_t *a, unsigned a_len, + uint32_t *b, unsigned b_len) +{ + uint32_t carry = 0; + for (unsigned i = 0; i < dst_len; i++) { + uint64_t sum = carry; + if (i < a_len) + sum += a[i]; + if (i < b_len) + sum += b[i]; + dst[i] = sum; + carry = sum >> 32; + } + + /* Now compute overflow */ + + for (unsigned i = dst_len; i < a_len; i++) { + if (a[i]) + return true; + } + + for (unsigned i = dst_len; i < b_len; i++) { + if (b[i]) + return true; + } + + return carry; +} +#define ubm_add_u32arr(dst, a, b) \ + _ubm_add_u32arr(dst, ARRAY_SIZE(dst), a, ARRAY_SIZE(a), b, ARRAY_SIZE(b)) + +static inline bool +_ubm_mul_u32arr(uint32_t *dst, unsigned dst_len, + uint32_t *a, unsigned a_len, + uint32_t *b, unsigned b_len) +{ + memset(dst, 0, dst_len * sizeof(*dst)); + + bool overflow = false; + + for (unsigned i = 0; i < a_len; i++) { + uint32_t carry = 0; + for (unsigned j = 0; j < b_len; j++) { + /* The maximum values of a[i] and b[i] are UINT32_MAX so the maximum + * value of tmp is UINT32_MAX * UINT32_MAX. The maximum value that + * will fit in tmp is + * + * UINT64_MAX = UINT32_MAX << 32 + UINT32_MAX + * = UINT32_MAX * (UINT32_MAX + 1) + UINT32_MAX + * = UINT32_MAX * UINT32_MAX + 2 * UINT32_MAX + * + * so we're guaranteed that we can add in two more 32-bit values + * without overflowing tmp. + */ + uint64_t tmp = (uint64_t)a[i] * (uint64_t)b[j]; + tmp += carry; + if (i + j < dst_len) { + tmp += dst[i + j]; + dst[i + j] = tmp; + carry = tmp >> 32; + } else { + /* We're trying to write a value that doesn't fit */ + overflow = overflow || tmp > 0; + break; + } + } + if (i + b_len < dst_len) + dst[i + b_len] = carry; + else + overflow = overflow || carry > 0; + } + + return overflow; +} +#define ubm_mul_u32arr(dst, a, b) \ + _ubm_mul_u32arr(dst, ARRAY_SIZE(dst), a, ARRAY_SIZE(a), b, ARRAY_SIZE(b)) + +#endif /* UTIL_BIGMATH_H */ diff --git a/src/util/meson.build b/src/util/meson.build index 027bc5b9d0d..9a99d60c158 100644 --- a/src/util/meson.build +++ b/src/util/meson.build @@ -23,6 +23,7 @@ inc_util = include_directories('.') subdir('xmlpool') files_mesa_util = files( + 'bigmath.h', 'bitscan.c', 'bitscan.h', 'bitset.h', -- 2.30.2