RISC-V: Support long double math

Long double for RISC-V is using 128 bit IEEE 754 format like Aarch64,
so we reference AArch64 to support that.

2 files changed, 66 insertions, 1 deletions

diff --git a/newlib/libc/include/math.h b/newlib/libc/include/math.h
index 87f51335f..5e92d2662 100644
--- a/newlib/libc/include/math.h
+++ b/newlib/libc/include/math.h
@@ -446,7 +446,8 @@ extern float hypotf (float, float);
    are implemented independently from newlib to be able to use optimized
    assembler functions despite using the Microsoft x86_64 ABI. */
 #if defined (_LDBL_EQ_DBL) || defined (__CYGWIN__) || \
-	defined(__aarch64__) || defined(__i386__) || defined(__x86_64__)
+	defined(__aarch64__) || defined(__i386__) || defined(__x86_64__) || \
+	defined(__riscv)
 /* Reentrant ANSI C functions.  */
 #ifndef __math_68881
 extern long double atanl (long double);
diff --git a/newlib/libc/machine/riscv/machine/_fpmath.h b/newlib/libc/machine/riscv/machine/_fpmath.h
new file mode 100644
index 000000000..fa62ae81c
--- /dev/null
+++ b/newlib/libc/machine/riscv/machine/_fpmath.h
@@ -0,0 +1,64 @@
+/*-
+ * Copyright (c) 2002, 2003 David Schultz <das@FreeBSD.ORG>
+ * Copyright (2) 2014 The FreeBSD Foundation
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+/*
+ * Change unsigned int/long used by FreeBSD to fixed width types because
+ * ilp32 has a different size for unsigned long. --joel (20 Aug 2022)
+ */
+#include <stdint.h>
+
+union IEEEl2bits {
+	long double	e;
+	struct {
+		uint64_t	manl	:64;
+		uint64_t	manh	:48;
+		uint32_t	exp	:15;
+		uint32_t	sign	:1;
+	} bits;
+	/* TODO andrew: Check the packing here */
+	struct {
+		uint64_t	manl	:64;
+		uint64_t	manh	:48;
+		uint32_t	expsign	:16;
+	} xbits;
+};
+
+#define	LDBL_NBIT	0
+#define	LDBL_IMPLICIT_NBIT
+#define	mask_nbit_l(u)	((void)0)
+
+#define	LDBL_MANH_SIZE	48
+#define	LDBL_MANL_SIZE	64
+
+#define	LDBL_TO_ARRAY32(u, a) do {			\
+	(a)[0] = (uint32_t)(u).bits.manl;		\
+	(a)[1] = (uint32_t)((u).bits.manl >> 32);	\
+	(a)[2] = (uint32_t)(u).bits.manh;		\
+	(a)[3] = (uint32_t)((u).bits.manh >> 32);	\
+} while(0)