4
0
mirror of git://sourceware.org/git/newlib-cygwin.git synced 2025-01-22 15:07:43 +08:00
Craig Blackmore 73bce6597c newlib: Fix long double for unsupported rounding modes and exceptions
RISC-V newlib fails to build for soft float multilibs since long double
support was enabled in:

  commit 04798b7bb69571452d2cfc7e0b052a9bbd3b619d
  Author: Kito Cheng <kito.cheng@sifive.com>
  Date:   Mon Dec 4 15:41:39 2023 +0800

      RISC-V: Support long double math

      Long double for RISC-V is using 128 bit IEEE 754 format like Aarch64,
      so we reference AArch64 to support that.

The RISC-V soft floating point environment only supports the
FE_TONEAREST rounding mode and does not support exceptions.  Guard long
double rounding and exception support with ifdefs based on the presence
of the relevant rounding modes and exceptions.

Tested on gcc/g++ testsuite using RISC-V GNU Newlib Toolchain built by
riscv-gnu-toolchain with multilibs:

    riscv-sim/-march=rv32i/-mabi=ilp32/-mcmodel=medlow
    riscv-sim/-march=rv32iac/-mabi=ilp32/-mcmodel=medlow
    riscv-sim/-march=rv32im/-mabi=ilp32/-mcmodel=medlow
    riscv-sim/-march=rv32imac/-mabi=ilp32/-mcmodel=medlow
    riscv-sim/-march=rv32imafc/-mabi=ilp32f/-mcmodel=medlow
    riscv-sim/-march=rv64imac/-mabi=lp64/-mcmodel=medlow

Co-authored-by: Simon Cook <simon.cook@embecosm.com>
2023-12-20 16:54:22 -05:00

63 lines
2.1 KiB
C

/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2005 David Schultz <das@FreeBSD.ORG>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
#include <fenv.h>
#include <math.h>
#ifndef type
__FBSDID("$FreeBSD$");
#define type double
#define roundit rint
#define dtype long
#define fn lrint
#endif
/*
* C99 says we should not raise a spurious inexact exception when an
* invalid exception is raised. Unfortunately, the set of inputs
* that overflows depends on the rounding mode when 'dtype' has more
* significant bits than 'type'. Hence, we bend over backwards for the
* sake of correctness; an MD implementation could be more efficient.
*/
dtype
fn(type x)
{
fenv_t env;
dtype d;
feholdexcept(&env);
d = (dtype)roundit(x);
#if defined(FE_INVALID) && defined(FE_INEXACT)
if (fetestexcept(FE_INVALID))
feclearexcept(FE_INEXACT);
#endif
feupdateenv(&env);
return (d);
}