diff options
Diffstat (limited to 'lib/builtins/floatuntidf.c')
-rw-r--r-- | lib/builtins/floatuntidf.c | 75 |
1 files changed, 36 insertions, 39 deletions
diff --git a/lib/builtins/floatuntidf.c b/lib/builtins/floatuntidf.c index 0f2f6f279..e69e65c1a 100644 --- a/lib/builtins/floatuntidf.c +++ b/lib/builtins/floatuntidf.c @@ -1,44 +1,41 @@ -/* ===-- floatuntidf.c - Implement __floatuntidf ---------------------------=== - * - * 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 __floatuntidf for the compiler_rt library. - * - * ===----------------------------------------------------------------------=== - */ +//===-- floatuntidf.c - Implement __floatuntidf ---------------------------===// +// +// 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 __floatuntidf for the compiler_rt library. +// +//===----------------------------------------------------------------------===// #include "int_lib.h" #ifdef CRT_HAS_128BIT -/* 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 - * tu_int is a 128 bit integral type - */ +// Assumption: double is a IEEE 64 bit floating point type +// tu_int is a 128 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 COMPILER_RT_ABI double __floatuntidf(tu_int a) { if (a == 0) return 0.0; const unsigned N = sizeof(tu_int) * CHAR_BIT; - int sd = N - __clzti2(a); /* number of significant digits */ - int e = sd - 1; /* exponent */ + int sd = N - __clzti2(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; @@ -49,25 +46,25 @@ COMPILER_RT_ABI double __floatuntidf(tu_int a) { a = (a >> (sd - (DBL_MANT_DIG + 2))) | ((a & ((tu_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 & ((tu_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 = ((e + 1023) << 20) | /* exponent */ - ((su_int)(a >> 32) & 0x000FFFFF); /* mantissa-high */ - fb.u.s.low = (su_int)a; /* mantissa-low */ + fb.u.s.high = ((e + 1023) << 20) | // exponent + ((su_int)(a >> 32) & 0x000FFFFF); // mantissa-high + fb.u.s.low = (su_int)a; // mantissa-low return fb.f; } -#endif /* CRT_HAS_128BIT */ +#endif // CRT_HAS_128BIT |