| // Copyright (c) Facebook, Inc. and its affiliates. |
| // All rights reserved. |
| // |
| // Copyright 2019 Google LLC |
| // |
| // This source code is licensed under the BSD-style license found in the |
| // LICENSE file in the root directory of this source tree. |
| |
| #pragma once |
| |
| #if defined(__cplusplus) && (__cplusplus >= 201103L) |
| #include <climits> |
| #include <cstdint> |
| #include <cstdbool> |
| #include <cassert> |
| #else |
| #include <limits.h> |
| #include <stdint.h> |
| #include <stdbool.h> |
| #include <assert.h> |
| #endif |
| |
| #include <fp16.h> |
| |
| #include <xnnpack/common.h> |
| |
| |
| #if defined(__clang__) && !defined(__pnacl__) |
| #if __clang_major__ == 3 && __clang_minor__ >= 7 || __clang_major__ > 3 |
| #define XNN_IGNORE_SHIFT_BASE_UB __attribute__((__no_sanitize__("shift-base"))) |
| #else |
| #define XNN_IGNORE_SHIFT_BASE_UB |
| #endif |
| #elif defined(__GNUC__) |
| #if __GNUC__ >= 8 |
| #define XNN_IGNORE_SHIFT_BASE_UB __attribute__((__no_sanitize__("shift-base"))) |
| #elif __GNUC__ == 4 && __GNUC_MINOR__ >= 9 || __GNUC__ > 4 |
| // 4.9 <= gcc < 8 support ubsan, but doesn't support no_sanitize attribute |
| #define XNN_IGNORE_SHIFT_BASE_UB |
| #ifndef XNN_USE_SHIFT_BASE_UB_WORKAROUND |
| #define XNN_USE_SHIFT_BASE_UB_WORKAROUND 1 |
| #endif |
| #else |
| #define XNN_IGNORE_SHIFT_BASE_UB |
| #endif |
| #else |
| #define XNN_IGNORE_SHIFT_BASE_UB |
| #endif |
| |
| XNN_IGNORE_SHIFT_BASE_UB |
| inline static int32_t asr_s32(int32_t x, uint32_t n) { |
| #ifdef XNN_USE_SHIFT_BASE_UB_WORKAROUND |
| #if XNN_ARCH_X86_64 || XNN_ARCH_ARM64 |
| return (int32_t) ((uint64_t) (int64_t) x >> n); |
| #else |
| return x >= 0 ? x >> n : ~(~x >> n); |
| #endif |
| #else |
| return x >> n; |
| #endif |
| } |
| |
| XNN_IGNORE_SHIFT_BASE_UB |
| inline static int64_t asr_s64(int64_t x, uint32_t n) { |
| #ifdef XNN_USE_SHIFT_BASE_UB_WORKAROUND |
| return x >= 0 ? x >> n : ~(~x >> n); |
| #else |
| return x >> n; |
| #endif |
| } |
| |
| inline static uint8_t scalar_requantize_precise( |
| int32_t value, |
| float scale, |
| uint8_t zero_point, |
| uint8_t qmin, |
| uint8_t qmax) |
| { |
| assert(scale < 1.0f); |
| assert(scale >= 0x1.0p-32f); |
| |
| const uint32_t scale_bits = fp32_to_bits(scale); |
| const uint32_t multiplier = (scale_bits & UINT32_C(0x007FFFFF)) | UINT32_C(0x00800000); |
| const uint32_t shift = 127 + 23 - (scale_bits >> 23); |
| assert(shift >= 24); |
| assert(shift < 56); |
| |
| // Compute absolute value of input as unsigned 32-bit int. |
| // All further computations will work with unsigned values to avoid undefined behaviour on signed operations. |
| const uint32_t abs_value = (value >= 0) ? (uint32_t) value : -(uint32_t) value; |
| |
| // Compute full 64-bit product of 32-bit factors |
| const uint64_t product = (uint64_t) abs_value * (uint64_t) multiplier; |
| |
| // Shift the full 64-bit product right with rounding. |
| // Rounding is performed towards closest integer, with midpoints rounded up (same as away from zero). |
| const uint64_t rounding = UINT64_C(1) << (shift - 1); |
| const uint32_t abs_scaled_value = (uint32_t) ((product + rounding) >> shift); |
| |
| // Copy the sign of input to scaled absolute input value. |
| const int32_t scaled_value = (int32_t) (value >= 0 ? abs_scaled_value : -abs_scaled_value); |
| |
| // Clamp scaled value with zero point between smin and smax. |
| int32_t clamped_value = scaled_value; |
| const int32_t smin = (int32_t) (uint32_t) qmin - (int32_t) (uint32_t) zero_point; |
| if (clamped_value < smin) { |
| clamped_value = smin; |
| } |
| const int32_t smax = (int32_t) (uint32_t) qmax - (int32_t) (uint32_t) zero_point; |
| if (clamped_value > smax) { |
| clamped_value = smax; |
| } |
| |
| // Add zero point to clamped value. |
| const int32_t biased_value = clamped_value + (int32_t) (uint32_t) zero_point; |
| |
| return biased_value; |
| } |