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43cfdf8f48
This patch currently only affects aarch64. The roundtoint and converttoint internal functions are only called with small values, so 32 bit result is enough for converttoint and it is a signed int conversion so the return type is changed to int32_t. The original idea was to help the compiler keeping the result in uint64_t, then it's clear that no sign extension is needed and there is no accidental undefined or implementation defined signed int arithmetics. But it turns out gcc does a good job with inlining so changing the type has no overhead and the semantics of the conversion is less surprising this way. Since we want to allow the asuint64 (x + 0x1.8p52) style conversion, the top bits were never usable and the existing code ensures that only the bottom 32 bits of the conversion result are used. On aarch64 the neon intrinsics (which round ties to even) are changed to round and lround (which round ties away from zero) this does not affect the results in a significant way, but more portable (relies on round and lround being inlined which works with -fno-math-errno). The TOINT_SHIFT and TOINT_RINT macros were removed, only keep separate code paths for TOINT_INTRINSICS and !TOINT_INTRINSICS. * sysdeps/aarch64/fpu/math_private.h (roundtoint): Use round. (converttoint): Use lround. * sysdeps/ieee754/flt-32/math_config.h (roundtoint): Declare and document the semantics when TOINT_INTRINSICS is set. (converttoint): Likewise. (TOINT_RINT): Remove. (TOINT_SHIFT): Remove. * sysdeps/ieee754/flt-32/e_expf.c (__expf): Remove the TOINT_RINT code path.
321 lines
8.6 KiB
C
321 lines
8.6 KiB
C
/* Private floating point rounding and exceptions handling. AArch64 version.
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Copyright (C) 2014-2018 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#ifndef AARCH64_MATH_PRIVATE_H
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#define AARCH64_MATH_PRIVATE_H 1
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#include <fenv.h>
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#include <fpu_control.h>
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#include <stdint.h>
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#include <math.h>
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static __always_inline void
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libc_feholdexcept_aarch64 (fenv_t *envp)
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{
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fpu_control_t fpcr;
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fpu_control_t new_fpcr;
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fpu_fpsr_t fpsr;
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fpu_fpsr_t new_fpsr;
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_FPU_GETCW (fpcr);
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_FPU_GETFPSR (fpsr);
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envp->__fpcr = fpcr;
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envp->__fpsr = fpsr;
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/* Clear exception flags and set all exceptions to non-stop. */
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new_fpcr = fpcr & ~(FE_ALL_EXCEPT << FE_EXCEPT_SHIFT);
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new_fpsr = fpsr & ~FE_ALL_EXCEPT;
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if (__glibc_unlikely (new_fpcr != fpcr))
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_FPU_SETCW (new_fpcr);
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if (new_fpsr != fpsr)
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_FPU_SETFPSR (new_fpsr);
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}
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#define libc_feholdexcept libc_feholdexcept_aarch64
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#define libc_feholdexceptf libc_feholdexcept_aarch64
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#define libc_feholdexceptl libc_feholdexcept_aarch64
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static __always_inline void
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libc_fesetround_aarch64 (int round)
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{
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fpu_control_t fpcr;
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_FPU_GETCW (fpcr);
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/* Check whether rounding modes are different. */
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round = (fpcr ^ round) & _FPU_FPCR_RM_MASK;
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/* Set new rounding mode if different. */
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if (__glibc_unlikely (round != 0))
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_FPU_SETCW (fpcr ^ round);
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}
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#define libc_fesetround libc_fesetround_aarch64
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#define libc_fesetroundf libc_fesetround_aarch64
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#define libc_fesetroundl libc_fesetround_aarch64
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static __always_inline void
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libc_feholdexcept_setround_aarch64 (fenv_t *envp, int round)
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{
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fpu_control_t fpcr;
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fpu_control_t new_fpcr;
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fpu_fpsr_t fpsr;
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fpu_fpsr_t new_fpsr;
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_FPU_GETCW (fpcr);
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_FPU_GETFPSR (fpsr);
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envp->__fpcr = fpcr;
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envp->__fpsr = fpsr;
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/* Clear exception flags, set all exceptions to non-stop,
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and set new rounding mode. */
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new_fpcr = fpcr & ~((FE_ALL_EXCEPT << FE_EXCEPT_SHIFT) | _FPU_FPCR_RM_MASK);
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new_fpcr |= round;
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new_fpsr = fpsr & ~FE_ALL_EXCEPT;
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if (__glibc_unlikely (new_fpcr != fpcr))
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_FPU_SETCW (new_fpcr);
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if (new_fpsr != fpsr)
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_FPU_SETFPSR (new_fpsr);
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}
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#define libc_feholdexcept_setround libc_feholdexcept_setround_aarch64
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#define libc_feholdexcept_setroundf libc_feholdexcept_setround_aarch64
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#define libc_feholdexcept_setroundl libc_feholdexcept_setround_aarch64
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static __always_inline int
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libc_fetestexcept_aarch64 (int ex)
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{
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fpu_fpsr_t fpsr;
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_FPU_GETFPSR (fpsr);
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return fpsr & ex & FE_ALL_EXCEPT;
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}
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#define libc_fetestexcept libc_fetestexcept_aarch64
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#define libc_fetestexceptf libc_fetestexcept_aarch64
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#define libc_fetestexceptl libc_fetestexcept_aarch64
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static __always_inline void
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libc_fesetenv_aarch64 (const fenv_t *envp)
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{
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fpu_control_t fpcr;
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fpu_control_t new_fpcr;
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_FPU_GETCW (fpcr);
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new_fpcr = envp->__fpcr;
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if (__glibc_unlikely (fpcr != new_fpcr))
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_FPU_SETCW (new_fpcr);
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_FPU_SETFPSR (envp->__fpsr);
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}
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#define libc_fesetenv libc_fesetenv_aarch64
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#define libc_fesetenvf libc_fesetenv_aarch64
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#define libc_fesetenvl libc_fesetenv_aarch64
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#define libc_feresetround_noex libc_fesetenv_aarch64
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#define libc_feresetround_noexf libc_fesetenv_aarch64
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#define libc_feresetround_noexl libc_fesetenv_aarch64
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static __always_inline int
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libc_feupdateenv_test_aarch64 (const fenv_t *envp, int ex)
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{
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fpu_control_t fpcr;
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fpu_control_t new_fpcr;
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fpu_fpsr_t fpsr;
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fpu_fpsr_t new_fpsr;
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int excepts;
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_FPU_GETCW (fpcr);
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_FPU_GETFPSR (fpsr);
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/* Merge current exception flags with the saved fenv. */
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excepts = fpsr & FE_ALL_EXCEPT;
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new_fpcr = envp->__fpcr;
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new_fpsr = envp->__fpsr | excepts;
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if (__glibc_unlikely (fpcr != new_fpcr))
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_FPU_SETCW (new_fpcr);
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if (fpsr != new_fpsr)
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_FPU_SETFPSR (new_fpsr);
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/* Raise the exceptions if enabled in the new FP state. */
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if (__glibc_unlikely (excepts & (new_fpcr >> FE_EXCEPT_SHIFT)))
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__feraiseexcept (excepts);
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return excepts & ex;
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}
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#define libc_feupdateenv_test libc_feupdateenv_test_aarch64
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#define libc_feupdateenv_testf libc_feupdateenv_test_aarch64
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#define libc_feupdateenv_testl libc_feupdateenv_test_aarch64
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static __always_inline void
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libc_feupdateenv_aarch64 (const fenv_t *envp)
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{
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libc_feupdateenv_test_aarch64 (envp, 0);
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}
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#define libc_feupdateenv libc_feupdateenv_aarch64
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#define libc_feupdateenvf libc_feupdateenv_aarch64
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#define libc_feupdateenvl libc_feupdateenv_aarch64
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static __always_inline void
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libc_feholdsetround_aarch64 (fenv_t *envp, int round)
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{
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fpu_control_t fpcr;
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fpu_fpsr_t fpsr;
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_FPU_GETCW (fpcr);
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_FPU_GETFPSR (fpsr);
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envp->__fpcr = fpcr;
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envp->__fpsr = fpsr;
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/* Check whether rounding modes are different. */
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round = (fpcr ^ round) & _FPU_FPCR_RM_MASK;
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/* Set new rounding mode if different. */
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if (__glibc_unlikely (round != 0))
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_FPU_SETCW (fpcr ^ round);
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}
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#define libc_feholdsetround libc_feholdsetround_aarch64
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#define libc_feholdsetroundf libc_feholdsetround_aarch64
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#define libc_feholdsetroundl libc_feholdsetround_aarch64
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static __always_inline void
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libc_feresetround_aarch64 (fenv_t *envp)
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{
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fpu_control_t fpcr;
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int round;
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_FPU_GETCW (fpcr);
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/* Check whether rounding modes are different. */
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round = (envp->__fpcr ^ fpcr) & _FPU_FPCR_RM_MASK;
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/* Restore the rounding mode if it was changed. */
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if (__glibc_unlikely (round != 0))
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_FPU_SETCW (fpcr ^ round);
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}
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#define libc_feresetround libc_feresetround_aarch64
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#define libc_feresetroundf libc_feresetround_aarch64
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#define libc_feresetroundl libc_feresetround_aarch64
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/* We have support for rounding mode context. */
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#define HAVE_RM_CTX 1
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static __always_inline void
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libc_feholdsetround_aarch64_ctx (struct rm_ctx *ctx, int r)
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{
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fpu_control_t fpcr;
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int round;
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_FPU_GETCW (fpcr);
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ctx->env.__fpcr = fpcr;
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/* Check whether rounding modes are different. */
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round = (fpcr ^ r) & _FPU_FPCR_RM_MASK;
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ctx->updated_status = round != 0;
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/* Set the rounding mode if changed. */
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if (__glibc_unlikely (round != 0))
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_FPU_SETCW (fpcr ^ round);
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}
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#define libc_feholdsetround_ctx libc_feholdsetround_aarch64_ctx
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#define libc_feholdsetroundf_ctx libc_feholdsetround_aarch64_ctx
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#define libc_feholdsetroundl_ctx libc_feholdsetround_aarch64_ctx
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static __always_inline void
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libc_feresetround_aarch64_ctx (struct rm_ctx *ctx)
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{
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/* Restore the rounding mode if updated. */
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if (__glibc_unlikely (ctx->updated_status))
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_FPU_SETCW (ctx->env.__fpcr);
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}
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#define libc_feresetround_ctx libc_feresetround_aarch64_ctx
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#define libc_feresetroundf_ctx libc_feresetround_aarch64_ctx
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#define libc_feresetroundl_ctx libc_feresetround_aarch64_ctx
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static __always_inline void
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libc_feholdsetround_noex_aarch64_ctx (struct rm_ctx *ctx, int r)
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{
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fpu_control_t fpcr;
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fpu_fpsr_t fpsr;
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int round;
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_FPU_GETCW (fpcr);
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_FPU_GETFPSR (fpsr);
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ctx->env.__fpcr = fpcr;
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ctx->env.__fpsr = fpsr;
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/* Check whether rounding modes are different. */
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round = (fpcr ^ r) & _FPU_FPCR_RM_MASK;
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ctx->updated_status = round != 0;
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/* Set the rounding mode if changed. */
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if (__glibc_unlikely (round != 0))
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_FPU_SETCW (fpcr ^ round);
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}
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#define libc_feholdsetround_noex_ctx libc_feholdsetround_noex_aarch64_ctx
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#define libc_feholdsetround_noexf_ctx libc_feholdsetround_noex_aarch64_ctx
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#define libc_feholdsetround_noexl_ctx libc_feholdsetround_noex_aarch64_ctx
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static __always_inline void
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libc_feresetround_noex_aarch64_ctx (struct rm_ctx *ctx)
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{
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/* Restore the rounding mode if updated. */
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if (__glibc_unlikely (ctx->updated_status))
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_FPU_SETCW (ctx->env.__fpcr);
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/* Write new FPSR to restore exception flags. */
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_FPU_SETFPSR (ctx->env.__fpsr);
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}
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#define libc_feresetround_noex_ctx libc_feresetround_noex_aarch64_ctx
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#define libc_feresetround_noexf_ctx libc_feresetround_noex_aarch64_ctx
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#define libc_feresetround_noexl_ctx libc_feresetround_noex_aarch64_ctx
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/* Use inline round and lround instructions. */
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#define TOINT_INTRINSICS 1
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static inline double_t
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roundtoint (double_t x)
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{
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return round (x);
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}
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static inline int32_t
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converttoint (double_t x)
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{
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return lround (x);
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}
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#include_next <math_private.h>
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#endif
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