RISC-V: Generic <math.h> and soft-fp Routines

This patch contains the miscellaneous math routines and headers we have
implemented for RISC-V.  This includes things from <math.h> that aren't
completely ISA-generic, floating-point bit manipulation, and soft-fp
hooks.

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

        * sysdeps/riscv/bits/fenv.h: New file.
        * sysdeps/riscv/e_sqrtl.c: Likewise.
        * sysdeps/riscv/fpu_control.h: Likewise.
        * sysdeps/riscv/math-tests.h: Likewise.
        * sysdeps/riscv/nofpu/Implies: Likewise.
        * sysdeps/riscv/sfp-machine.h: Likewise.
        * sysdeps/riscv/tininess.h: Likewise.

1 files changed, 101 insertions, 0 deletions

diff --git a/sysdeps/riscv/sfp-machine.h b/sysdeps/riscv/sfp-machine.h
new file mode 100644
index 0000000000..e3884433f3
--- /dev/null
+++ b/sysdeps/riscv/sfp-machine.h
@@ -0,0 +1,101 @@
+/* RISC-V softfloat definitions
+   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 <fenv.h>
+#include <fpu_control.h>
+
+#if __riscv_xlen == 32
+
+# error "rv32i-based targets are not supported"
+
+#else
+
+# define _FP_W_TYPE_SIZE		64
+# define _FP_W_TYPE		unsigned long long
+# define _FP_WS_TYPE		signed long long
+# define _FP_I_TYPE		long long
+
+# define _FP_MUL_MEAT_S(R, X, Y)					\
+  _FP_MUL_MEAT_1_imm (_FP_WFRACBITS_S, R, X, Y)
+# define _FP_MUL_MEAT_D(R, X, Y)					\
+  _FP_MUL_MEAT_1_wide (_FP_WFRACBITS_D, R, X, Y, umul_ppmm)
+# define _FP_MUL_MEAT_Q(R, X, Y)					\
+  _FP_MUL_MEAT_2_wide_3mul (_FP_WFRACBITS_Q, R, X, Y, umul_ppmm)
+
+# define _FP_MUL_MEAT_DW_S(R, X, Y)					\
+  _FP_MUL_MEAT_DW_1_imm (_FP_WFRACBITS_S, R, X, Y)
+# define _FP_MUL_MEAT_DW_D(R, X, Y)					\
+  _FP_MUL_MEAT_DW_1_wide (_FP_WFRACBITS_D, R, X, Y, umul_ppmm)
+# define _FP_MUL_MEAT_DW_Q(R, X, Y)					\
+  _FP_MUL_MEAT_DW_2_wide_3mul (_FP_WFRACBITS_Q, R, X, Y, umul_ppmm)
+
+# define _FP_DIV_MEAT_S(R, X, Y)	_FP_DIV_MEAT_1_imm (S, R, X, Y, _FP_DIV_HELP_imm)
+# define _FP_DIV_MEAT_D(R, X, Y)	_FP_DIV_MEAT_1_udiv_norm (D, R, X, Y)
+# define _FP_DIV_MEAT_Q(R, X, Y)	_FP_DIV_MEAT_2_udiv (Q, R, X, Y)
+
+# define _FP_NANFRAC_S		_FP_QNANBIT_S
+# define _FP_NANFRAC_D		_FP_QNANBIT_D
+# define _FP_NANFRAC_Q		_FP_QNANBIT_Q, 0
+
+#endif
+
+#define _FP_NANSIGN_S		0
+#define _FP_NANSIGN_D		0
+#define _FP_NANSIGN_Q		0
+
+#define _FP_KEEPNANFRACP 0
+#define _FP_QNANNEGATEDP 0
+
+#define _FP_CHOOSENAN(fs, wc, R, X, Y, OP)	\
+  do {						\
+    R##_s = _FP_NANSIGN_##fs;			\
+    _FP_FRAC_SET_##wc (R, _FP_NANFRAC_##fs);	\
+    R##_c = FP_CLS_NAN;				\
+  } while (0)
+
+#define _FP_DECL_EX		int _frm __attribute__ ((unused));
+#define FP_ROUNDMODE		_frm
+
+#define FP_RND_NEAREST		FE_TONEAREST
+#define FP_RND_ZERO		FE_TOWARDZERO
+#define FP_RND_PINF		FE_UPWARD
+#define FP_RND_MINF		FE_DOWNWARD
+
+#define FP_EX_INVALID		FE_INVALID
+#define FP_EX_OVERFLOW		FE_OVERFLOW
+#define FP_EX_UNDERFLOW		FE_UNDERFLOW
+#define FP_EX_DIVZERO		FE_DIVBYZERO
+#define FP_EX_INEXACT		FE_INEXACT
+
+#define _FP_TININESS_AFTER_ROUNDING 1
+
+#ifdef __riscv_flen
+# define FP_INIT_ROUNDMODE			\
+do {						\
+  __asm__ volatile ("frrm %0" : "=r" (_frm));	\
+} while (0)
+
+# define FP_HANDLE_EXCEPTIONS					\
+do {								\
+  if (__builtin_expect (_fex, 0))				\
+    __asm__ volatile ("csrs fflags, %0" : : "rK" (_fex));	\
+} while (0)
+#else
+# define FP_INIT_ROUNDMODE	_frm = FP_RND_NEAREST
+#endif