diff options
Diffstat (limited to 'compiler-rt/lib/builtins/floatdidf.c')
| -rw-r--r-- | compiler-rt/lib/builtins/floatdidf.c | 87 |
1 files changed, 41 insertions, 46 deletions
diff --git a/compiler-rt/lib/builtins/floatdidf.c b/compiler-rt/lib/builtins/floatdidf.c index c14d52fd371..b45041316e3 100644 --- a/compiler-rt/lib/builtins/floatdidf.c +++ b/compiler-rt/lib/builtins/floatdidf.c @@ -1,31 +1,28 @@ -/*===-- floatdidf.c - Implement __floatdidf -------------------------------=== - * - * Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. - * See https://llvm.org/LICENSE.txt for license information. - * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception - * - *===----------------------------------------------------------------------=== - * - * This file implements __floatdidf for the compiler_rt library. - * - *===----------------------------------------------------------------------=== - */ +//===-- floatdidf.c - Implement __floatdidf -------------------------------===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// +// +// This file implements __floatdidf for the compiler_rt library. +// +//===----------------------------------------------------------------------===// #include "int_lib.h" -/* Returns: convert a to a double, rounding toward even. */ +// Returns: convert a to a double, rounding toward even. -/* Assumption: double is a IEEE 64 bit floating point type - * di_int is a 64 bit integral type - */ +// Assumption: double is a IEEE 64 bit floating point type +// di_int is a 64 bit integral type -/* seee eeee eeee mmmm mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm mmmm mmmm - * mmmm */ +// seee eeee eeee mmmm mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm mmmm mmmm +// mmmm #ifndef __SOFT_FP__ -/* Support for systems that have hardware floating-point; we'll set the inexact - * flag as a side-effect of this computation. - */ +// Support for systems that have hardware floating-point; we'll set the inexact +// flag as a side-effect of this computation. COMPILER_RT_ABI double __floatdidf(di_int a) { static const double twop52 = 4503599627370496.0; // 0x1.0p52 @@ -44,10 +41,9 @@ COMPILER_RT_ABI double __floatdidf(di_int a) { } #else -/* Support for systems that don't have hardware floating-point; there are no - * flags to set, and we don't want to code-gen to an unknown soft-float - * implementation. - */ +// Support for systems that don't have hardware floating-point; there are no +// flags to set, and we don't want to code-gen to an unknown soft-float +// implementation. COMPILER_RT_ABI double __floatdidf(di_int a) { if (a == 0) @@ -55,17 +51,16 @@ COMPILER_RT_ABI double __floatdidf(di_int a) { const unsigned N = sizeof(di_int) * CHAR_BIT; const di_int s = a >> (N - 1); a = (a ^ s) - s; - int sd = N - __builtin_clzll(a); /* number of significant digits */ - int e = sd - 1; /* exponent */ + int sd = N - __builtin_clzll(a); // number of significant digits + int e = sd - 1; // exponent if (sd > DBL_MANT_DIG) { - /* start: 0000000000000000000001xxxxxxxxxxxxxxxxxxxxxxPQxxxxxxxxxxxxxxxxxx - * finish: 000000000000000000000000000000000000001xxxxxxxxxxxxxxxxxxxxxxPQR - * 12345678901234567890123456 - * 1 = msb 1 bit - * P = bit DBL_MANT_DIG-1 bits to the right of 1 - * Q = bit DBL_MANT_DIG bits to the right of 1 - * R = "or" of all bits to the right of Q - */ + // start: 0000000000000000000001xxxxxxxxxxxxxxxxxxxxxxPQxxxxxxxxxxxxxxxxxx + // finish: 000000000000000000000000000000000000001xxxxxxxxxxxxxxxxxxxxxxPQR + // 12345678901234567890123456 + // 1 = msb 1 bit + // P = bit DBL_MANT_DIG-1 bits to the right of 1 + // Q = bit DBL_MANT_DIG bits to the right of 1 + // R = "or" of all bits to the right of Q switch (sd) { case DBL_MANT_DIG + 1: a <<= 1; @@ -76,25 +71,25 @@ COMPILER_RT_ABI double __floatdidf(di_int a) { a = ((du_int)a >> (sd - (DBL_MANT_DIG + 2))) | ((a & ((du_int)(-1) >> ((N + DBL_MANT_DIG + 2) - sd))) != 0); }; - /* finish: */ - a |= (a & 4) != 0; /* Or P into R */ - ++a; /* round - this step may add a significant bit */ - a >>= 2; /* dump Q and R */ - /* a is now rounded to DBL_MANT_DIG or DBL_MANT_DIG+1 bits */ + // finish: + a |= (a & 4) != 0; // Or P into R + ++a; // round - this step may add a significant bit + a >>= 2; // dump Q and R + // a is now rounded to DBL_MANT_DIG or DBL_MANT_DIG+1 bits if (a & ((du_int)1 << DBL_MANT_DIG)) { a >>= 1; ++e; } - /* a is now rounded to DBL_MANT_DIG bits */ + // a is now rounded to DBL_MANT_DIG bits } else { a <<= (DBL_MANT_DIG - sd); - /* a is now rounded to DBL_MANT_DIG bits */ + // a is now rounded to DBL_MANT_DIG bits } double_bits fb; - fb.u.s.high = ((su_int)s & 0x80000000) | /* sign */ - ((e + 1023) << 20) | /* exponent */ - ((su_int)(a >> 32) & 0x000FFFFF); /* mantissa-high */ - fb.u.s.low = (su_int)a; /* mantissa-low */ + fb.u.s.high = ((su_int)s & 0x80000000) | // sign + ((e + 1023) << 20) | // exponent + ((su_int)(a >> 32) & 0x000FFFFF); // mantissa-high + fb.u.s.low = (su_int)a; // mantissa-low return fb.f; } #endif |
