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.

1 files changed, 52 insertions, 0 deletions

diff --git a/sysdeps/riscv/rv64/rvd/s_rint.c b/sysdeps/riscv/rv64/rvd/s_rint.c
new file mode 100644
index 0000000000..ef2380ea7f
--- /dev/null
+++ b/sysdeps/riscv/rv64/rvd/s_rint.c
@@ -0,0 +1,52 @@
+/* rint().  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>
+#include <libm-alias-double.h>
+#include <stdint.h>
+
+double
+__rint (double x)
+{
+  bool nan;
+  double mag;
+
+  nan = isnan (x);
+  mag = fabs (x);
+
+  if (nan)
+    return x + x;
+
+  if (mag < (1ULL << __DBL_MANT_DIG__))
+    {
+      int64_t i;
+      double new_x;
+
+      asm ("fcvt.l.d %0, %1" : "=r" (i) : "f" (x));
+      asm ("fcvt.d.l %0, %1" : "=f" (new_x) : "r" (i));
+
+      /* rint(-0) == -0, and in general we'll always have the same
+	 sign as our input.  */
+      x = copysign (new_x, x);
+    }
+
+  return x;
+}
+
+libm_alias_double (__rint, rint)