fp_fixint_impl.inc (2250B)
1 //===-- lib/fixdfsi.c - Double-precision -> integer conversion ----*- C -*-===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This file implements float to integer conversion for the 10 // compiler-rt library. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #include "fp_lib.h" 15 16 #ifndef FP_FIX_SUFFIX 17 #error "fp_fixint_impl.inc: FP_FIX_SUFFIX must be defined before #include" 18 #endif 19 20 #ifndef FP_FIX_IMPL_PASTE_ 21 #define FP_FIX_IMPL_PASTE_(a, b) a##_##b 22 #define FP_FIX_IMPL_PASTE(a, b) FP_FIX_IMPL_PASTE_(a, b) 23 #endif 24 25 #ifdef __fixint 26 #undef __fixint 27 #endif 28 #define __fixint FP_FIX_IMPL_PASTE(__fixint, FP_FIX_SUFFIX) 29 30 static inline fixint_t __fixint(fp_t a) { 31 const fixint_t fixint_max = (fixint_t)((~(fixuint_t)0) / 2); 32 const fixint_t fixint_min = -fixint_max - 1; 33 // Break a into sign, exponent, significand parts. 34 const rep_t aRep = toRep(a); 35 const rep_t aAbs = aRep & absMask; 36 const fixint_t sign = aRep & signBit ? -1 : 1; 37 const int exponent = (aAbs >> significandBits) - exponentBias; 38 const rep_t significand = (aAbs & significandMask) | implicitBit; 39 40 // If exponent is negative, the result is zero. 41 if (exponent < 0) 42 return 0; 43 44 // If the value is too large for the integer type, saturate. 45 if ((unsigned)exponent >= sizeof(fixint_t) * CHAR_BIT) 46 return sign == 1 ? fixint_max : fixint_min; 47 48 // If 0 <= exponent < significandBits, right shift to get the result. 49 // Otherwise, shift left. 50 if (exponent < significandBits) 51 return sign * (significand >> (significandBits - exponent)); 52 else 53 return sign * ((fixuint_t)significand << (exponent - significandBits)); 54 } 55 56 // FP_FIX_SUFFIX, fixint_t, fixuint_t intentionally left defined: the 57 // caller's `return __fixint(a);` line is parsed AFTER this include, and 58 // the `__fixint` macro re-expands FP_FIX_SUFFIX at that point. The 59 // caller (per-op .c) is responsible for #undef'ing them at its bottom 60 // so consolidated builds can stack multiple per-op snippets in one TU.