mirror of
https://github.com/jart/cosmopolitan.git
synced 2025-01-31 03:27:39 +00:00
7e0a09feec
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
84 lines
2.7 KiB
C
84 lines
2.7 KiB
C
/* clang-format off */
|
|
/* ===-- floatuntixf.c - Implement __floatuntixf ---------------------------===
|
|
*
|
|
* 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 __floatuntixf for the compiler_rt library.
|
|
*
|
|
* ===----------------------------------------------------------------------===
|
|
*/
|
|
|
|
__static_yoink("huge_compiler_rt_license");
|
|
|
|
#include "third_party/compiler_rt/int_lib.h"
|
|
|
|
#ifdef CRT_HAS_128BIT
|
|
|
|
/* 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
|
|
* tu_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
|
|
*/
|
|
|
|
COMPILER_RT_ABI long double
|
|
__floatuntixf(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 */
|
|
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
|
|
*/
|
|
switch (sd)
|
|
{
|
|
case LDBL_MANT_DIG + 1:
|
|
a <<= 1;
|
|
break;
|
|
case LDBL_MANT_DIG + 2:
|
|
break;
|
|
default:
|
|
a = (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 */
|
|
if (a & ((tu_int)1 << LDBL_MANT_DIG))
|
|
{
|
|
a >>= 1;
|
|
++e;
|
|
}
|
|
/* a is now rounded to LDBL_MANT_DIG bits */
|
|
}
|
|
else
|
|
{
|
|
a <<= (LDBL_MANT_DIG - sd);
|
|
/* a is now rounded to LDBL_MANT_DIG bits */
|
|
}
|
|
long_double_bits fb;
|
|
fb.u.high.s.low = (e + 16383); /* exponent */
|
|
fb.u.low.all = (du_int)a; /* mantissa */
|
|
return fb.f;
|
|
}
|
|
|
|
#endif
|