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
85 lines
3 KiB
C
85 lines
3 KiB
C
/* clang-format off */
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//===-- lib/floattitf.c - int128 -> quad-precision conversion -----*- C -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is dual licensed under the MIT and the University of Illinois Open
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// Source Licenses. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements ti_int to quad-precision conversion for the
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// compiler-rt library in the IEEE-754 default round-to-nearest, ties-to-even
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// mode.
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//
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//===----------------------------------------------------------------------===//
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__static_yoink("huge_compiler_rt_license");
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#define QUAD_PRECISION
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#include "third_party/compiler_rt/fp_lib.inc"
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#include "third_party/compiler_rt/int_lib.h"
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/* Returns: convert a ti_int to a fp_t, rounding toward even. */
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/* Assumption: fp_t is a IEEE 128 bit floating point type
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* ti_int is a 128 bit integral type
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*/
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/* seee eeee eeee eeee mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm |
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* mmmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm
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*/
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#if defined(CRT_HAS_128BIT) && defined(CRT_LDBL_128BIT)
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COMPILER_RT_ABI fp_t
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__floattitf(ti_int a) {
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if (a == 0)
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return 0.0;
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const unsigned N = sizeof(ti_int) * CHAR_BIT;
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const ti_int s = a >> (N-1);
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a = (a ^ s) - s;
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int sd = N - __clzti2(a); /* number of significant digits */
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int e = sd - 1; /* exponent */
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if (sd > LDBL_MANT_DIG) {
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/* start: 0000000000000000000001xxxxxxxxxxxxxxxxxxxxxxPQxxxxxxxxxxxxxxxxxx
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* finish: 000000000000000000000000000000000000001xxxxxxxxxxxxxxxxxxxxxxPQR
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* 12345678901234567890123456
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* 1 = msb 1 bit
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* P = bit LDBL_MANT_DIG-1 bits to the right of 1
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* Q = bit LDBL_MANT_DIG bits to the right of 1
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* R = "or" of all bits to the right of Q
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*/
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switch (sd) {
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case LDBL_MANT_DIG + 1:
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a <<= 1;
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break;
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case LDBL_MANT_DIG + 2:
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break;
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default:
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a = ((tu_int)a >> (sd - (LDBL_MANT_DIG+2))) |
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((a & ((tu_int)(-1) >> ((N + LDBL_MANT_DIG+2) - sd))) != 0);
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};
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/* finish: */
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a |= (a & 4) != 0; /* Or P into R */
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++a; /* round - this step may add a significant bit */
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a >>= 2; /* dump Q and R */
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/* a is now rounded to LDBL_MANT_DIG or LDBL_MANT_DIG+1 bits */
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if (a & ((tu_int)1 << LDBL_MANT_DIG)) {
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a >>= 1;
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++e;
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}
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/* a is now rounded to LDBL_MANT_DIG bits */
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} else {
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a <<= (LDBL_MANT_DIG - sd);
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/* a is now rounded to LDBL_MANT_DIG bits */
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}
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long_double_bits fb;
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fb.u.high.all = (s & 0x8000000000000000LL) /* sign */
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| (du_int)(e + 16383) << 48 /* exponent */
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| ((a >> 64) & 0x0000ffffffffffffLL); /* significand */
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fb.u.low.all = (du_int)(a);
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return fb.f;
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}
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#endif
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