mirror of
https://github.com/jart/cosmopolitan.git
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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
88 lines
2.7 KiB
C
88 lines
2.7 KiB
C
/* clang-format off */
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/*===-- floatundisf.c - Implement __floatundisf ---------------------------===
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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 __floatundisf for the compiler_rt library.
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*
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*===----------------------------------------------------------------------===
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*/
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__static_yoink("huge_compiler_rt_license");
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/* Returns: convert a to a float, rounding toward even. */
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/* Assumption: float is a IEEE 32 bit floating point type
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* du_int is a 64 bit integral type
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*/
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/* seee eeee emmm mmmm mmmm mmmm mmmm mmmm */
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#include "third_party/compiler_rt/int_lib.h"
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COMPILER_RT_ABI float
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__floatundisf(du_int a)
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{
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if (a == 0)
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return 0.0F;
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const unsigned N = sizeof(du_int) * CHAR_BIT;
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int sd = N - __builtin_clzll(a); /* number of significant digits */
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int e = sd - 1; /* 8 exponent */
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if (sd > FLT_MANT_DIG)
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{
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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 FLT_MANT_DIG-1 bits to the right of 1
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* Q = bit FLT_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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{
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case FLT_MANT_DIG + 1:
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a <<= 1;
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break;
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case FLT_MANT_DIG + 2:
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break;
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default:
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a = (a >> (sd - (FLT_MANT_DIG+2))) |
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((a & ((du_int)(-1) >> ((N + FLT_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 FLT_MANT_DIG or FLT_MANT_DIG+1 bits */
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if (a & ((du_int)1 << FLT_MANT_DIG))
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{
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a >>= 1;
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++e;
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}
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/* a is now rounded to FLT_MANT_DIG bits */
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}
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else
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{
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a <<= (FLT_MANT_DIG - sd);
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/* a is now rounded to FLT_MANT_DIG bits */
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}
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float_bits fb;
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fb.u = ((e + 127) << 23) | /* exponent */
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((su_int)a & 0x007FFFFF); /* mantissa */
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return fb.f;
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}
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#if defined(__ARM_EABI__)
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#if defined(COMPILER_RT_ARMHF_TARGET)
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AEABI_RTABI float __aeabi_ul2f(du_int a) {
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return __floatundisf(a);
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}
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#else
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AEABI_RTABI float __aeabi_ul2f(du_int a) COMPILER_RT_ALIAS(__floatundisf);
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#endif
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#endif
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