1 // SPDX-License-Identifier: MIT 2 /* 3 * Copyright 2023 Advanced Micro Devices, Inc. 4 * 5 * Permission is hereby granted, free of charge, to any person obtaining a 6 * copy of this software and associated documentation files (the "Software"), 7 * to deal in the Software without restriction, including without limitation 8 * the rights to use, copy, modify, merge, publish, distribute, sublicense, 9 * and/or sell copies of the Software, and to permit persons to whom the 10 * Software is furnished to do so, subject to the following conditions: 11 * 12 * The above copyright notice and this permission notice shall be included in 13 * all copies or substantial portions of the Software. 14 * 15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 18 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR 19 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, 20 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR 21 * OTHER DEALINGS IN THE SOFTWARE. 22 * 23 * Authors: AMD 24 * 25 */ 26 #include "dm_services.h" 27 #include "custom_float.h" 28 29 static bool build_custom_float(struct fixed31_32 value, 30 const struct custom_float_format *format, 31 bool *negative, 32 uint32_t *mantissa, 33 uint32_t *exponenta) 34 { 35 uint32_t exp_offset = (1 << (format->exponenta_bits - 1)) - 1; 36 37 const struct fixed31_32 mantissa_constant_plus_max_fraction = 38 dc_fixpt_from_fraction((1LL << (format->mantissa_bits + 1)) - 1, 39 1LL << format->mantissa_bits); 40 41 struct fixed31_32 mantiss; 42 43 if (dc_fixpt_eq(value, dc_fixpt_zero)) { 44 *negative = false; 45 *mantissa = 0; 46 *exponenta = 0; 47 return true; 48 } 49 50 if (dc_fixpt_lt(value, dc_fixpt_zero)) { 51 *negative = format->sign; 52 value = dc_fixpt_neg(value); 53 } else { 54 *negative = false; 55 } 56 57 if (dc_fixpt_lt(value, dc_fixpt_one)) { 58 uint32_t i = 1; 59 60 do { 61 value = dc_fixpt_shl(value, 1); 62 ++i; 63 } while (dc_fixpt_lt(value, dc_fixpt_one)); 64 65 --i; 66 67 if (exp_offset <= i) { 68 *mantissa = 0; 69 *exponenta = 0; 70 return true; 71 } 72 73 *exponenta = exp_offset - i; 74 } else if (dc_fixpt_le(mantissa_constant_plus_max_fraction, value)) { 75 uint32_t i = 1; 76 77 do { 78 value = dc_fixpt_shr(value, 1); 79 ++i; 80 } while (dc_fixpt_lt(mantissa_constant_plus_max_fraction, value)); 81 82 *exponenta = exp_offset + i - 1; 83 } else { 84 *exponenta = exp_offset; 85 } 86 87 mantiss = dc_fixpt_sub(value, dc_fixpt_one); 88 89 if (dc_fixpt_lt(mantiss, dc_fixpt_zero) || 90 dc_fixpt_lt(dc_fixpt_one, mantiss)) 91 mantiss = dc_fixpt_zero; 92 else 93 mantiss = dc_fixpt_shl(mantiss, format->mantissa_bits); 94 95 *mantissa = dc_fixpt_floor(mantiss); 96 97 return true; 98 } 99 100 static bool setup_custom_float(const struct custom_float_format *format, 101 bool negative, 102 uint32_t mantissa, 103 uint32_t exponenta, 104 uint32_t *result) 105 { 106 uint32_t i = 0; 107 uint32_t j = 0; 108 uint32_t value = 0; 109 110 /* verification code: 111 * once calculation is ok we can remove it 112 */ 113 114 const uint32_t mantissa_mask = 115 (1 << (format->mantissa_bits + 1)) - 1; 116 117 const uint32_t exponenta_mask = 118 (1 << (format->exponenta_bits + 1)) - 1; 119 120 if (mantissa & ~mantissa_mask) { 121 BREAK_TO_DEBUGGER(); 122 mantissa = mantissa_mask; 123 } 124 125 if (exponenta & ~exponenta_mask) { 126 BREAK_TO_DEBUGGER(); 127 exponenta = exponenta_mask; 128 } 129 130 /* end of verification code */ 131 132 while (i < format->mantissa_bits) { 133 uint32_t mask = 1 << i; 134 135 if (mantissa & mask) 136 value |= mask; 137 138 ++i; 139 } 140 141 while (j < format->exponenta_bits) { 142 uint32_t mask = 1 << j; 143 144 if (exponenta & mask) 145 value |= mask << i; 146 147 ++j; 148 } 149 150 if (negative && format->sign) 151 value |= 1 << (i + j); 152 153 *result = value; 154 155 return true; 156 } 157 158 bool convert_to_custom_float_format(struct fixed31_32 value, 159 const struct custom_float_format *format, 160 uint32_t *result) 161 { 162 uint32_t mantissa; 163 uint32_t exponenta; 164 bool negative; 165 166 return build_custom_float(value, format, &negative, &mantissa, &exponenta) && 167 setup_custom_float(format, 168 negative, 169 mantissa, 170 exponenta, 171 result); 172 } 173 174