RISC-V: Hard Float Support

This patch contains hardware floating-point support for the RISC-V ISA.
While we currently only support hard-float systems with both the F and D
extensions, I've left the F-specific code split out into seperate
folders in order to ease adding support for F-only and RV32I-based
systems in the future.  I gave this a quick once-over and believe I've
removed all the code that implements RV32IF, RV32IFD, and RV64IF
targets.

2018-01-29  Palmer Dabbelt  <palmer@sifive.com>

        * sysdeps/riscv/rv64/rvd/s_ceil.c: New file.
        * sysdeps/riscv/rv64/rvd/s_floor.c: Likewise.
        * sysdeps/riscv/rv64/rvd/s_llrint.c: Likewise.
        * sysdeps/riscv/rv64/rvd/s_llround.c: Likewise.
        * sysdeps/riscv/rv64/rvd/s_lrint.c: Likewise.
        * sysdeps/riscv/rv64/rvd/s_lround.c: Likewise.
        * sysdeps/riscv/rv64/rvd/s_nearbyint.c: Likewise.
        * sysdeps/riscv/rv64/rvd/s_rint.c: Likewise.
        * sysdeps/riscv/rv64/rvd/s_round.c: Likewise.
        * sysdeps/riscv/rv64/rvd/s_roundeven.c: Likewise.
        * sysdeps/riscv/rv64/rvd/s_trunc.c: Likewise.
        * sysdeps/riscv/rv64/rvf/s_llrintf.c: Likewise.
        * sysdeps/riscv/rv64/rvf/s_llroundf.c: Likewise.
        * sysdeps/riscv/rv64/rvf/s_lrintf.c: Likewise.
        * sysdeps/riscv/rv64/rvf/s_lroundf.c: Likewise.
        * sysdeps/riscv/rvd/e_sqrt.c: Likewise.
        * sysdeps/riscv/rvd/s_copysign.c: Likewise.
        * sysdeps/riscv/rvd/s_finite.c: Likewise.
        * sysdeps/riscv/rvd/s_fma.c: Likewise.
        * sysdeps/riscv/rvd/s_fmax.c: Likewise.
        * sysdeps/riscv/rvd/s_fmin.c: Likewise.
        * sysdeps/riscv/rvd/s_fpclassify.c: Likewise.
        * sysdeps/riscv/rvd/s_isinf.c: Likewise.
        * sysdeps/riscv/rvd/s_isnan.c: Likewise.
        * sysdeps/riscv/rvd/s_issignaling.c: Likewise.
        * sysdeps/riscv/rvf/e_sqrtf.c: Likewise.
        * sysdeps/riscv/rvf/fclrexcpt.c: Likewise.
        * sysdeps/riscv/rvf/fegetenv.c: Likewise.
        * sysdeps/riscv/rvf/fegetmode.c: Likewise.
        * sysdeps/riscv/rvf/fegetround.c: Likewise.
        * sysdeps/riscv/rvf/feholdexcpt.c: Likewise.
        * sysdeps/riscv/rvf/fesetenv.c: Likewise.
        * sysdeps/riscv/rvf/fesetexcept.c: Likewise.
        * sysdeps/riscv/rvf/fesetmode.c: Likewise.
        * sysdeps/riscv/rvf/fesetround.c: Likewise.
        * sysdeps/riscv/rvf/feupdateenv.c: Likewise.
        * sysdeps/riscv/rvf/fgetexcptflg.c: Likewise.
        * sysdeps/riscv/rvf/fraiseexcpt.c: Likewise.
        * sysdeps/riscv/rvf/fsetexcptflg.c: Likewise.
        * sysdeps/riscv/rvf/ftestexcept.c: Likewise.
        * sysdeps/riscv/rvf/get-rounding-mode.h: Likewise.
        * sysdeps/riscv/rvf/math_private.h: Likewise.
        * sysdeps/riscv/rvf/s_ceilf.c: Likewise.
        * sysdeps/riscv/rvf/s_copysignf.c: Likewise.
        * sysdeps/riscv/rvf/s_finitef.c: Likewise.
        * sysdeps/riscv/rvf/s_floorf.c: Likewise.
        * sysdeps/riscv/rvf/s_fmaf.c: Likewise.
        * sysdeps/riscv/rvf/s_fmaxf.c: Likewise.
        * sysdeps/riscv/rvf/s_fminf.c: Likewise.
        * sysdeps/riscv/rvf/s_fpclassifyf.c: Likewise.
        * sysdeps/riscv/rvf/s_isinff.c: Likewise.
        * sysdeps/riscv/rvf/s_isnanf.c: Likewise.
        * sysdeps/riscv/rvf/s_issignalingf.c: Likewise.
        * sysdeps/riscv/rvf/s_nearbyintf.c: Likewise.
        * sysdeps/riscv/rvf/s_rintf.c: Likewise.
        * sysdeps/riscv/rvf/s_roundevenf.c: Likewise.
        * sysdeps/riscv/rvf/s_roundf.c: Likewise.
        * sysdeps/riscv/rvf/s_truncf.c: Likewise.

10 files changed, 289 insertions, 0 deletions

diff --git a/sysdeps/riscv/rvd/e_sqrt.c b/sysdeps/riscv/rvd/e_sqrt.c
new file mode 100644
index 0000000000..66627eec21
--- /dev/null
+++ b/sysdeps/riscv/rvd/e_sqrt.c
@@ -0,0 +1,27 @@
+/* Double precision floating point square root.  RISC-V version.
+   Copyright (C) 2017-2018 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
+   <http://www.gnu.org/licenses/>.  */
+
+#include <math.h>
+
+double
+__ieee754_sqrt (double x)
+{
+  asm ("fsqrt.d %0, %1" : "=f" (x) : "f" (x));
+  return x;
+}
+strong_alias (__ieee754_sqrt, __sqrt_finite)
diff --git a/sysdeps/riscv/rvd/s_copysign.c b/sysdeps/riscv/rvd/s_copysign.c
new file mode 100644
index 0000000000..36fef55aa2
--- /dev/null
+++ b/sysdeps/riscv/rvd/s_copysign.c
@@ -0,0 +1,28 @@
+/* Copy sign bit between floating-point values.  RISC-V version.
+   Copyright (C) 2017-2018 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
+   <http://www.gnu.org/licenses/>.  */
+
+#include <math.h>
+#include <libm-alias-double.h>
+
+double
+__copysign (double x, double y)
+{
+  asm ("fsgnj.d %0, %1, %2" : "=f" (x) : "f" (x), "f" (y));
+  return x;
+}
+libm_alias_double (__copysign, copysign)
diff --git a/sysdeps/riscv/rvd/s_finite.c b/sysdeps/riscv/rvd/s_finite.c
new file mode 100644
index 0000000000..402ae3fa3a
--- /dev/null
+++ b/sysdeps/riscv/rvd/s_finite.c
@@ -0,0 +1,28 @@
+/* finite().  RISC-V version.
+   Copyright (C) 2017-2018 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
+   <http://www.gnu.org/licenses/>.  */
+
+#include <math.h>
+#include <math_private.h>
+
+int
+__finite (double x)
+{
+  return _FCLASS (x) & ~(_FCLASS_INF | _FCLASS_NAN);
+}
+hidden_def (__finite)
+weak_alias (__finite, finite)
diff --git a/sysdeps/riscv/rvd/s_fma.c b/sysdeps/riscv/rvd/s_fma.c
new file mode 100644
index 0000000000..165557962f
--- /dev/null
+++ b/sysdeps/riscv/rvd/s_fma.c
@@ -0,0 +1,30 @@
+/* Double precision floating point fused multiply-add.  RISC-V version.
+   Copyright (C) 2017-2018 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
+   <http://www.gnu.org/licenses/>.  */
+
+#include <math.h>
+#include <fenv.h>
+#include <ieee754.h>
+#include <libm-alias-double.h>
+
+double
+__fma (double x, double y, double z)
+{
+  asm ("fmadd.d %0, %1, %2, %3" : "=f" (x) : "f" (x), "f" (y), "f" (z));
+  return x;
+}
+libm_alias_double (__fma, fma)
diff --git a/sysdeps/riscv/rvd/s_fmax.c b/sysdeps/riscv/rvd/s_fmax.c
new file mode 100644
index 0000000000..ef8f1344ce
--- /dev/null
+++ b/sysdeps/riscv/rvd/s_fmax.c
@@ -0,0 +1,28 @@
+/* fmax().  RISC-V version.
+   Copyright (C) 2017-2018 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
+   <http://www.gnu.org/licenses/>.  */
+
+#include <math.h>
+#include <libm-alias-double.h>
+
+double
+__fmax (double x, double y)
+{
+  asm ("fmax.d %0, %1, %2" : "=f" (x) : "f" (x), "f" (y));
+  return x;
+}
+libm_alias_double (__fmax, fmax)
diff --git a/sysdeps/riscv/rvd/s_fmin.c b/sysdeps/riscv/rvd/s_fmin.c
new file mode 100644
index 0000000000..c6ff24cefb
--- /dev/null
+++ b/sysdeps/riscv/rvd/s_fmin.c
@@ -0,0 +1,28 @@
+/* fmin().  RISC-V version.
+   Copyright (C) 2017-2018 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
+   <http://www.gnu.org/licenses/>.  */
+
+#include <math.h>
+#include <libm-alias-double.h>
+
+double
+__fmin (double x, double y)
+{
+  asm ("fmin.d %0, %1, %2" : "=f" (x) : "f" (x), "f" (y));
+  return x;
+}
+libm_alias_double (__fmin, fmin)
diff --git a/sysdeps/riscv/rvd/s_fpclassify.c b/sysdeps/riscv/rvd/s_fpclassify.c
new file mode 100644
index 0000000000..fe693c2f4a
--- /dev/null
+++ b/sysdeps/riscv/rvd/s_fpclassify.c
@@ -0,0 +1,36 @@
+/* fpclassify().  RISC-V version.
+   Copyright (C) 2017-2018 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
+   <http://www.gnu.org/licenses/>.  */
+
+#include <math.h>
+#include <math_private.h>
+
+int
+__fpclassify (double x)
+{
+  int cls = _FCLASS (x);
+  if (__builtin_expect (cls & _FCLASS_NORM, _FCLASS_NORM))
+    return FP_NORMAL;
+  if (__builtin_expect (cls & _FCLASS_ZERO, _FCLASS_ZERO))
+    return FP_ZERO;
+  if (__builtin_expect (cls & _FCLASS_SUBNORM, _FCLASS_SUBNORM))
+    return FP_SUBNORMAL;
+  if (__builtin_expect (cls & _FCLASS_INF, _FCLASS_INF))
+    return FP_INFINITE;
+  return FP_NAN;
+}
+libm_hidden_def (__fpclassify)
diff --git a/sysdeps/riscv/rvd/s_isinf.c b/sysdeps/riscv/rvd/s_isinf.c
new file mode 100644
index 0000000000..1b9767a718
--- /dev/null
+++ b/sysdeps/riscv/rvd/s_isinf.c
@@ -0,0 +1,29 @@
+/* isinf().  RISC-V version.
+   Copyright (C) 2017-2018 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
+   <http://www.gnu.org/licenses/>.  */
+
+#include <math.h>
+#include <math_private.h>
+
+int
+__isinf (double x)
+{
+  int cls = _FCLASS (x);
+  return -((cls & _FCLASS_MINF) ? 1 : 0) | ((cls & _FCLASS_PINF) ? 1 : 0);
+}
+hidden_def (__isinf)
+weak_alias (__isinf, isinf)
diff --git a/sysdeps/riscv/rvd/s_isnan.c b/sysdeps/riscv/rvd/s_isnan.c
new file mode 100644
index 0000000000..3739de7ec7
--- /dev/null
+++ b/sysdeps/riscv/rvd/s_isnan.c
@@ -0,0 +1,28 @@
+/* isnan().  RISC_V version.
+   Copyright (C) 2017-2018 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
+   <http://www.gnu.org/licenses/>.  */
+
+#include <math.h>
+#include <math_private.h>
+
+int
+__isnan (double x)
+{
+  return (_FCLASS (x) & _FCLASS_NAN) != 0;
+}
+hidden_def (__isnan)
+weak_alias (__isnan, isnan)
diff --git a/sysdeps/riscv/rvd/s_issignaling.c b/sysdeps/riscv/rvd/s_issignaling.c
new file mode 100644
index 0000000000..1b65206e9a
--- /dev/null
+++ b/sysdeps/riscv/rvd/s_issignaling.c
@@ -0,0 +1,27 @@
+/* issignaling().  RISC-V version.
+   Copyright (C) 2017-2018 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
+   <http://www.gnu.org/licenses/>.  */
+
+#include <math.h>
+#include <math_private.h>
+
+int
+__issignaling (double x)
+{
+  return (_FCLASS (x) & _FCLASS_SNAN) != 0;
+}
+libm_hidden_def (__issignaling)