0d586d06a7
r303188 removed all the uses of aliases for EABI functions from compiler-rt, because some of them had mismatched calling conventions. Obviously, we can't use aliases for functions which don't have the same calling convention, but that's only an issue for floating-point functions with the hardfloat ABI. In other cases, the stubs increase size and reduce performance for no benefit. This patch adds back the aliases, with appropriate checks to make sure they're only used in cases where the calling convention matches. llvm-svn: 314851
116 lines
3.6 KiB
C
116 lines
3.6 KiB
C
/*===-- floatdidf.c - Implement __floatdidf -------------------------------===
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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 __floatdidf for the compiler_rt library.
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*
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*===----------------------------------------------------------------------===
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*/
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#include "int_lib.h"
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/* Returns: convert a to a double, rounding toward even. */
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/* Assumption: double is a IEEE 64 bit floating point type
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* di_int is a 64 bit integral type
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*/
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/* seee eeee eeee mmmm mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm */
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#ifndef __SOFT_FP__
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/* Support for systems that have hardware floating-point; we'll set the inexact flag
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* as a side-effect of this computation.
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*/
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COMPILER_RT_ABI double
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__floatdidf(di_int a)
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{
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static const double twop52 = 4503599627370496.0; // 0x1.0p52
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static const double twop32 = 4294967296.0; // 0x1.0p32
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union { int64_t x; double d; } low = { .d = twop52 };
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const double high = (int32_t)(a >> 32) * twop32;
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low.x |= a & INT64_C(0x00000000ffffffff);
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const double result = (high - twop52) + low.d;
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return result;
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}
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#else
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/* Support for systems that don't have hardware floating-point; there are no flags to
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* set, and we don't want to code-gen to an unknown soft-float implementation.
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*/
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COMPILER_RT_ABI double
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__floatdidf(di_int a)
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{
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if (a == 0)
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return 0.0;
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const unsigned N = sizeof(di_int) * CHAR_BIT;
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const di_int s = a >> (N-1);
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a = (a ^ s) - s;
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int sd = N - __builtin_clzll(a); /* number of significant digits */
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int e = sd - 1; /* exponent */
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if (sd > DBL_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 DBL_MANT_DIG-1 bits to the right of 1
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* Q = bit DBL_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 DBL_MANT_DIG + 1:
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a <<= 1;
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break;
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case DBL_MANT_DIG + 2:
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break;
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default:
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a = ((du_int)a >> (sd - (DBL_MANT_DIG+2))) |
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((a & ((du_int)(-1) >> ((N + DBL_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 DBL_MANT_DIG or DBL_MANT_DIG+1 bits */
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if (a & ((du_int)1 << DBL_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 DBL_MANT_DIG bits */
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}
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else
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{
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a <<= (DBL_MANT_DIG - sd);
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/* a is now rounded to DBL_MANT_DIG bits */
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}
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double_bits fb;
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fb.u.s.high = ((su_int)s & 0x80000000) | /* sign */
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((e + 1023) << 20) | /* exponent */
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((su_int)(a >> 32) & 0x000FFFFF); /* mantissa-high */
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fb.u.s.low = (su_int)a; /* mantissa-low */
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return fb.f;
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}
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#endif
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#if defined(__ARM_EABI__)
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#if defined(COMPILER_RT_ARMHF_TARGET)
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AEABI_RTABI double __aeabi_l2d(di_int a) {
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return __floatdidf(a);
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}
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#else
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AEABI_RTABI double __aeabi_l2d(di_int a) COMPILER_RT_ALIAS(__floatdidf);
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#endif
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#endif
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