cosmopolitan/third_party/compiler_rt/floatsidf.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

64 lines
1.9 KiB
C

/* clang-format off */
//===-- lib/floatsidf.c - integer -> double-precision conversion --*- C -*-===//
//
// 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 integer to double-precision conversion for the
// compiler-rt library in the IEEE-754 default round-to-nearest, ties-to-even
// mode.
//
//===----------------------------------------------------------------------===//
__static_yoink("huge_compiler_rt_license");
#define DOUBLE_PRECISION
#include "third_party/compiler_rt/fp_lib.inc"
#include "third_party/compiler_rt/int_lib.h"
COMPILER_RT_ABI fp_t
__floatsidf(int a) {
const int aWidth = sizeof a * CHAR_BIT;
// Handle zero as a special case to protect clz
if (a == 0)
return fromRep(0);
// All other cases begin by extracting the sign and absolute value of a
rep_t sign = 0;
if (a < 0) {
sign = signBit;
a = -a;
}
// Exponent of (fp_t)a is the width of abs(a).
const int exponent = (aWidth - 1) - __builtin_clz(a);
rep_t result;
// Shift a into the significand field and clear the implicit bit. Extra
// cast to unsigned int is necessary to get the correct behavior for
// the input INT_MIN.
const int shift = significandBits - exponent;
result = (rep_t)(unsigned int)a << shift ^ implicitBit;
// Insert the exponent
result += (rep_t)(exponent + exponentBias) << significandBits;
// Insert the sign bit and return
return fromRep(result | sign);
}
#if defined(__ARM_EABI__)
#if defined(COMPILER_RT_ARMHF_TARGET)
AEABI_RTABI fp_t __aeabi_i2d(int a) {
return __floatsidf(a);
}
#else
AEABI_RTABI fp_t __aeabi_i2d(int a) COMPILER_RT_ALIAS(__floatsidf);
#endif
#endif