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authorDimitry Andric <dim@FreeBSD.org>2019-08-20 20:51:06 +0000
committerDimitry Andric <dim@FreeBSD.org>2019-08-20 20:51:06 +0000
commit8f3cadc28cb2bb9e8f9d69eeaaea1f57f2f7b2ab (patch)
tree05a2b6ec297fe6283d9557c791445d1daf88dcd0 /lib/builtins/floattidf.c
parent63714eb5809e39666dec2454c354195e76f916ba (diff)
downloadsrc-vendor/compiler-rt/compiler-rt-trunk-r366426.tar.gz
src-vendor/compiler-rt/compiler-rt-trunk-r366426.zip
Vendor import of stripped compiler-rt trunk r366426 (just before the release_90vendor/compiler-rt/compiler-rt-trunk-r366426
Diffstat (limited to 'lib/builtins/floattidf.c')
-rw-r--r--lib/builtins/floattidf.c134
1 files changed, 62 insertions, 72 deletions
diff --git a/lib/builtins/floattidf.c b/lib/builtins/floattidf.c
index 2702a3c8a2db..0a1c04bec82e 100644
--- a/lib/builtins/floattidf.c
+++ b/lib/builtins/floattidf.c
@@ -1,83 +1,73 @@
-/* ===-- floattidf.c - Implement __floattidf -------------------------------===
- *
- * The LLVM Compiler Infrastructure
- *
- * This file is dual licensed under the MIT and the University of Illinois Open
- * Source Licenses. See LICENSE.TXT for details.
- *
- * ===----------------------------------------------------------------------===
- *
- * This file implements __floattidf for the compiler_rt library.
- *
- * ===----------------------------------------------------------------------===
- */
+//===-- floattidf.c - Implement __floattidf -------------------------------===//
+//
+// 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 __floattidf 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
- * ti_int is a 128 bit integral type
- */
+// Assumption: double is a IEEE 64 bit floating point type
+// ti_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
-__floattidf(ti_int a)
-{
- if (a == 0)
- return 0.0;
- 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 */
- 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
- */
- switch (sd)
- {
- case DBL_MANT_DIG + 1:
- a <<= 1;
- break;
- case DBL_MANT_DIG + 2:
- break;
- default:
- a = ((tu_int)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 */
- if (a & ((tu_int)1 << DBL_MANT_DIG))
- {
- a >>= 1;
- ++e;
- }
- /* a is now rounded to DBL_MANT_DIG bits */
+COMPILER_RT_ABI double __floattidf(ti_int a) {
+ if (a == 0)
+ return 0.0;
+ 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
+ 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
+ switch (sd) {
+ case DBL_MANT_DIG + 1:
+ a <<= 1;
+ break;
+ case DBL_MANT_DIG + 2:
+ break;
+ default:
+ a = ((tu_int)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
+ if (a & ((tu_int)1 << DBL_MANT_DIG)) {
+ a >>= 1;
+ ++e;
}
- else
- {
- a <<= (DBL_MANT_DIG - sd);
- /* 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 */
- return fb.f;
+ // a is now rounded to DBL_MANT_DIG bits
+ } else {
+ a <<= (DBL_MANT_DIG - sd);
+ // 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
+ return fb.f;
}
-#endif /* CRT_HAS_128BIT */
+#endif // CRT_HAS_128BIT