LoongArch: Hard Float Support for float-point classification functions.

Use hardware Floating-point instruction fclass.{s/d} to implement
classification functions, i.e finite{f/ }, fpclassify{f/ }, isnan{f/ },
isinf{f/ }, issignaling{f/ }.

       *  sysdeps/loongarch/fpu/s_finite.c: New file.
       *  sysdeps/loongarch/fpu/s_finitef.c: Likewise.
       *  sysdeps/loongarch/fpu/s_fpclassify.c: Likewise.
       *  sysdeps/loongarch/fpu/s_fpclassifyf.c: Likewise.
       *  sysdeps/loongarch/fpu/s_isinf.c: Likewise.
       *  sysdeps/loongarch/fpu/s_isinff.c: Likewise.
       *  sysdeps/loongarch/fpu/s_isnan.c: Likewise.
       *  sysdeps/loongarch/fpu/s_isnanf.c: Likewise.
       *  sysdeps/loongarch/fpu/s_issignaling.c: Likewise.
       *  sysdeps/loongarch/fpu/s_issignalingf.c: Likewise.
       *  sysdeps/loongarch/fpu_control.h: Add _FCLASS_* macro.

1 files changed, 38 insertions, 0 deletions

diff --git a/sysdeps/loongarch/fpu/s_fpclassify.c b/sysdeps/loongarch/fpu/s_fpclassify.c
new file mode 100644
index 0000000..3f4d95d
--- /dev/null
+++ b/sysdeps/loongarch/fpu/s_fpclassify.c
@@ -0,0 +1,38 @@
+/* fpclassify().  LoongArch version.
+   Copyright (C) 2017-2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library.  If not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <math.h>
+#include <fenv_private.h>
+
+int
+__fpclassify (double x)
+{
+  int cls;
+  asm volatile ("fclass.d \t%0, %1" : "=f" (cls) : "f" (x));
+
+  if (__glibc_likely (!!(cls & _FCLASS_NORM)))
+    return FP_NORMAL;
+  if (__glibc_likely (!!(cls & _FCLASS_ZERO)))
+    return FP_ZERO;
+  if (__glibc_likely (!!(cls & _FCLASS_SUBNORM)))
+    return FP_SUBNORMAL;
+  if (__glibc_likely (!!(cls & _FCLASS_INF)))
+    return FP_INFINITE;
+  return FP_NAN;
+}
+libm_hidden_def (__fpclassify)