diff options
Diffstat (limited to 'compiler-rt/lib/builtins/floattixf.c')
| -rw-r--r-- | compiler-rt/lib/builtins/floattixf.c | 78 |
1 files changed, 37 insertions, 41 deletions
diff --git a/compiler-rt/lib/builtins/floattixf.c b/compiler-rt/lib/builtins/floattixf.c index fe145cbc4cc..23796f1bb56 100644 --- a/compiler-rt/lib/builtins/floattixf.c +++ b/compiler-rt/lib/builtins/floattixf.c @@ -1,30 +1,27 @@ -/* ===-- floattixf.c - Implement __floattixf -------------------------------=== - * - * 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 __floattixf for the compiler_rt library. - * - * ===----------------------------------------------------------------------=== - */ +//===-- floattixf.c - Implement __floattixf -------------------------------===// +// +// 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 __floattixf for the compiler_rt library. +// +//===----------------------------------------------------------------------===// #include "int_lib.h" #ifdef CRT_HAS_128BIT -/* Returns: convert a to a long double, rounding toward even. */ +// Returns: convert a to a long double, rounding toward even. -/* Assumption: long double is a IEEE 80 bit floating point type padded to 128 - * bits ti_int is a 128 bit integral type - */ +// Assumption: long double is a IEEE 80 bit floating point type padded to 128 +// bits ti_int is a 128 bit integral type -/* gggg gggg gggg gggg gggg gggg gggg gggg | gggg gggg gggg gggg seee eeee eeee - * eeee | 1mmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm - * mmmm mmmm mmmm - */ +// gggg gggg gggg gggg gggg gggg gggg gggg | gggg gggg gggg gggg seee eeee eeee +// eeee | 1mmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm +// mmmm mmmm mmmm COMPILER_RT_ABI long double __floattixf(ti_int a) { if (a == 0) @@ -32,17 +29,16 @@ COMPILER_RT_ABI long double __floattixf(ti_int a) { const unsigned N = sizeof(ti_int) * CHAR_BIT; const ti_int s = a >> (N - 1); a = (a ^ s) - s; - 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 > LDBL_MANT_DIG) { - /* start: 0000000000000000000001xxxxxxxxxxxxxxxxxxxxxxPQxxxxxxxxxxxxxxxxxx - * finish: 000000000000000000000000000000000000001xxxxxxxxxxxxxxxxxxxxxxPQR - * 12345678901234567890123456 - * 1 = msb 1 bit - * P = bit LDBL_MANT_DIG-1 bits to the right of 1 - * Q = bit LDBL_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 LDBL_MANT_DIG-1 bits to the right of 1 + // Q = bit LDBL_MANT_DIG bits to the right of 1 + // R = "or" of all bits to the right of Q switch (sd) { case LDBL_MANT_DIG + 1: a <<= 1; @@ -53,25 +49,25 @@ COMPILER_RT_ABI long double __floattixf(ti_int a) { a = ((tu_int)a >> (sd - (LDBL_MANT_DIG + 2))) | ((a & ((tu_int)(-1) >> ((N + LDBL_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 LDBL_MANT_DIG or LDBL_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 LDBL_MANT_DIG or LDBL_MANT_DIG+1 bits if (a & ((tu_int)1 << LDBL_MANT_DIG)) { a >>= 1; ++e; } - /* a is now rounded to LDBL_MANT_DIG bits */ + // a is now rounded to LDBL_MANT_DIG bits } else { a <<= (LDBL_MANT_DIG - sd); - /* a is now rounded to LDBL_MANT_DIG bits */ + // a is now rounded to LDBL_MANT_DIG bits } long_double_bits fb; - fb.u.high.s.low = ((su_int)s & 0x8000) | /* sign */ - (e + 16383); /* exponent */ - fb.u.low.all = (du_int)a; /* mantissa */ + fb.u.high.s.low = ((su_int)s & 0x8000) | // sign + (e + 16383); // exponent + fb.u.low.all = (du_int)a; // mantissa return fb.f; } -#endif /* CRT_HAS_128BIT */ +#endif // CRT_HAS_128BIT |
