disas/libvixl/vixl/utils.cc

   1 // Copyright 2015, ARM Limited
   2 // All rights reserved.
   3 //
   4 // Redistribution and use in source and binary forms, with or without
   5 // modification, are permitted provided that the following conditions are met:
   6 //
   7 //   * Redistributions of source code must retain the above copyright notice,
   8 //     this list of conditions and the following disclaimer.
   9 //   * Redistributions in binary form must reproduce the above copyright notice,
  10 //     this list of conditions and the following disclaimer in the documentation
  11 //     and/or other materials provided with the distribution.
  12 //   * Neither the name of ARM Limited nor the names of its contributors may be
  13 //     used to endorse or promote products derived from this software without
  14 //     specific prior written permission.
  15 //
  16 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS CONTRIBUTORS "AS IS" AND
  17 // ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  18 // WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  19 // DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
  20 // FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21 // DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  22 // SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  23 // CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  24 // OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  25 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  26
  27 #include "vixl/utils.h"
  28 #include <stdio.h>
  29
  30 namespace vixl {
  31
  32 uint32_t float_to_rawbits(float value) {
  33   uint32_t bits = 0;
  34   memcpy(&bits, &value, 4);
  35   return bits;
  36 }
  37
  38
  39 uint64_t double_to_rawbits(double value) {
  40   uint64_t bits = 0;
  41   memcpy(&bits, &value, 8);
  42   return bits;
  43 }
  44
  45
  46 float rawbits_to_float(uint32_t bits) {
  47   float value = 0.0;
  48   memcpy(&value, &bits, 4);
  49   return value;
  50 }
  51
  52
  53 double rawbits_to_double(uint64_t bits) {
  54   double value = 0.0;
  55   memcpy(&value, &bits, 8);
  56   return value;
  57 }
  58
  59
  60 uint32_t float_sign(float val) {
  61   uint32_t rawbits = float_to_rawbits(val);
  62   return unsigned_bitextract_32(31, 31, rawbits);
  63 }
  64
  65
  66 uint32_t float_exp(float val) {
  67   uint32_t rawbits = float_to_rawbits(val);
  68   return unsigned_bitextract_32(30, 23, rawbits);
  69 }
  70
  71
  72 uint32_t float_mantissa(float val) {
  73   uint32_t rawbits = float_to_rawbits(val);
  74   return unsigned_bitextract_32(22, 0, rawbits);
  75 }
  76
  77
  78 uint32_t double_sign(double val) {
  79   uint64_t rawbits = double_to_rawbits(val);
  80   return static_cast<uint32_t>(unsigned_bitextract_64(63, 63, rawbits));
  81 }
  82
  83
  84 uint32_t double_exp(double val) {
  85   uint64_t rawbits = double_to_rawbits(val);
  86   return static_cast<uint32_t>(unsigned_bitextract_64(62, 52, rawbits));
  87 }
  88
  89
  90 uint64_t double_mantissa(double val) {
  91   uint64_t rawbits = double_to_rawbits(val);
  92   return unsigned_bitextract_64(51, 0, rawbits);
  93 }
  94
  95
  96 float float_pack(uint32_t sign, uint32_t exp, uint32_t mantissa) {
  97   uint32_t bits = (sign << 31) | (exp << 23) | mantissa;
  98   return rawbits_to_float(bits);
  99 }
 100
 101
 102 double double_pack(uint64_t sign, uint64_t exp, uint64_t mantissa) {
 103   uint64_t bits = (sign << 63) | (exp << 52) | mantissa;
 104   return rawbits_to_double(bits);
 105 }
 106
 107
 108 int float16classify(float16 value) {
 109   uint16_t exponent_max = (1 << 5) - 1;
 110   uint16_t exponent_mask = exponent_max << 10;
 111   uint16_t mantissa_mask = (1 << 10) - 1;
 112
 113   uint16_t exponent = (value & exponent_mask) >> 10;
 114   uint16_t mantissa = value & mantissa_mask;
 115   if (exponent == 0) {
 116     if (mantissa == 0) {
 117       return FP_ZERO;
 118     }
 119     return FP_SUBNORMAL;
 120   } else if (exponent == exponent_max) {
 121     if (mantissa == 0) {
 122       return FP_INFINITE;
 123     }
 124     return FP_NAN;
 125   }
 126   return FP_NORMAL;
 127 }
 128
 129
 130 unsigned CountClearHalfWords(uint64_t imm, unsigned reg_size) {
 131   VIXL_ASSERT((reg_size % 8) == 0);
 132   int count = 0;
 133   for (unsigned i = 0; i < (reg_size / 16); i++) {
 134     if ((imm & 0xffff) == 0) {
 135       count++;
 136     }
 137     imm >>= 16;
 138   }
 139   return count;
 140 }
 141
 142 }  // namespace vixl