cosmopolitan/third_party/compiler_rt/floatdixf.c
Justine Tunney 7e0a09feec
Mint APE Loader v1.5
This change ports APE Loader to Linux AARCH64, so that Raspberry Pi
users can run programs like redbean, without the executable needing
to modify itself. Progress has also slipped into this change on the
issue of making progress better conforming to user expectations and
industry standards regarding which symbols we're allowed to declare
2023-07-26 13:54:49 -07:00

49 lines
1.5 KiB
C

/* clang-format off */
/* ===-- floatdixf.c - Implement __floatdixf -------------------------------===
*
* 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 __floatdixf for the compiler_rt library.
*
* ===----------------------------------------------------------------------===
*/
__static_yoink("huge_compiler_rt_license");
#if !_ARCH_PPC
#include "third_party/compiler_rt/int_lib.h"
/* 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
* di_int is a 64 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
*/
COMPILER_RT_ABI long double
__floatdixf(di_int a)
{
if (a == 0)
return 0.0;
const unsigned N = sizeof(di_int) * CHAR_BIT;
const di_int s = a >> (N-1);
a = (a ^ s) - s;
int clz = __builtin_clzll(a);
int e = (N - 1) - clz ; /* exponent */
long_double_bits fb;
fb.u.high.s.low = ((su_int)s & 0x00008000) | /* sign */
(e + 16383); /* exponent */
fb.u.low.all = a << clz; /* mantissa */
return fb.f;
}
#endif /* !_ARCH_PPC */