Clean up <machine/ieeefp.h> and make sure the rounding mode bits match the

hardware.  Implement fp[gs]etround(3) and fp[gs]etsticky(3) and tweak
the fp[gs]etmask(3) implementation to provide the right weak symbols.
This implementation deliberately ignores the additional
"round to nearest, away from zero" as this interface is derived from
i386-specific code and the i387 FPU doesn't implement such a rounding
mode.  This is a legacy API and code should use <fenv.h> instead.

ok drahn@

6 files changed, 122 insertions, 6 deletions

diff --git a/lib/libc/arch/riscv64/gen/fpgetmask.c b/lib/libc/arch/riscv64/gen/fpgetmask.c
index 6e94f99bd33..4d8fac984e2 100644
--- a/lib/libc/arch/riscv64/gen/fpgetmask.c
+++ b/lib/libc/arch/riscv64/gen/fpgetmask.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: fpgetmask.c,v 1.1 2021/04/28 08:22:56 kettenis Exp $	*/
+/*	$OpenBSD: fpgetmask.c,v 1.2 2021/04/29 17:19:18 kettenis Exp $	*/
 /*
  * Copyright (c) 2018 Mark Kettenis <kettenis@openbsd.org>
  *
@@ -17,10 +17,9 @@
 
 #include <ieeefp.h>
 
-__weak_alias(_fpgetmask,fpgetmask);
-
 fp_except
 fpgetmask(void)
 {
 	return 0;
 }
+DEF_WEAK(fpgetmask);
diff --git a/lib/libc/arch/riscv64/gen/fpgetround.c b/lib/libc/arch/riscv64/gen/fpgetround.c
new file mode 100644
index 00000000000..6d2351f9d1e
--- /dev/null
+++ b/lib/libc/arch/riscv64/gen/fpgetround.c
@@ -0,0 +1,29 @@
+/*	$OpenBSD: fpgetround.c,v 1.1 2021/04/29 17:19:18 kettenis Exp $	*/
+/*
+ * Copyright (c) 2021 Mark Kettenis <kettenis@openbsd.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/types.h>
+#include <ieeefp.h>
+
+fp_rnd
+fpgetround(void)
+{
+	uint32_t frm;
+
+	__asm volatile ("frrm %0" : "=r"(frm));
+	return frm & 0x3;
+}
+DEF_WEAK(fpgetround);
diff --git a/lib/libc/arch/riscv64/gen/fpgetsticky.c b/lib/libc/arch/riscv64/gen/fpgetsticky.c
new file mode 100644
index 00000000000..81a14b0dcda
--- /dev/null
+++ b/lib/libc/arch/riscv64/gen/fpgetsticky.c
@@ -0,0 +1,29 @@
+/*	$OpenBSD: fpgetsticky.c,v 1.1 2021/04/29 17:19:18 kettenis Exp $	*/
+/*
+ * Copyright (c) 2021 Mark Kettenis <kettenis@openbsd.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/types.h>
+#include <ieeefp.h>
+
+fp_except
+fpgetsticky(void)
+{
+	uint32_t fflags;
+
+	__asm volatile ("frflags %0" : "=r"(fflags));
+	return fflags;
+}
+DEF_WEAK(fpgetsticky);
diff --git a/lib/libc/arch/riscv64/gen/fpsetmask.c b/lib/libc/arch/riscv64/gen/fpsetmask.c
index 03485db6c93..d4b1edd5d79 100644
--- a/lib/libc/arch/riscv64/gen/fpsetmask.c
+++ b/lib/libc/arch/riscv64/gen/fpsetmask.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: fpsetmask.c,v 1.1 2021/04/28 08:22:56 kettenis Exp $	*/
+/*	$OpenBSD: fpsetmask.c,v 1.2 2021/04/29 17:19:18 kettenis Exp $	*/
 /*
  * Copyright (c) 2018 Mark Kettenis <kettenis@openbsd.org>
  *
@@ -17,10 +17,9 @@
 
 #include <ieeefp.h>
 
-__weak_alias(_fpsetmask,fpsetmask);
-
 fp_except
 fpsetmask(fp_except mask)
 {
 	return 0;
 }
+DEF_WEAK(fpsetmask);
diff --git a/lib/libc/arch/riscv64/gen/fpsetround.c b/lib/libc/arch/riscv64/gen/fpsetround.c
new file mode 100644
index 00000000000..e9e26b32466
--- /dev/null
+++ b/lib/libc/arch/riscv64/gen/fpsetround.c
@@ -0,0 +1,31 @@
+/*	$OpenBSD: fpsetround.c,v 1.1 2021/04/29 17:19:18 kettenis Exp $	*/
+/*
+ * Copyright (c) 2021 Mark Kettenis <kettenis@openbsd.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/types.h>
+#include <ieeefp.h>
+
+fp_rnd
+fpsetround(fp_rnd rnd_dir)
+{
+	uint32_t frm;
+
+	__asm volatile ("fsrm %0, %1" : "=r"(frm) : "r"(rnd_dir));
+
+	/* Truncating to 2 bits means both RNE and RMM become FP_RN. */
+	return frm & 0x3;
+}
+DEF_WEAK(fpsetround);
diff --git a/lib/libc/arch/riscv64/gen/fpsetsticky.c b/lib/libc/arch/riscv64/gen/fpsetsticky.c
new file mode 100644
index 00000000000..a7069c38b75
--- /dev/null
+++ b/lib/libc/arch/riscv64/gen/fpsetsticky.c
@@ -0,0 +1,29 @@
+/*	$OpenBSD: fpsetsticky.c,v 1.1 2021/04/29 17:19:18 kettenis Exp $	*/
+/*
+ * Copyright (c) 2021 Mark Kettenis <kettenis@openbsd.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/types.h>
+#include <ieeefp.h>
+
+fp_except
+fpsetsticky(fp_except sticky)
+{
+	uint32_t fflags;
+
+	__asm volatile ("fsflags %0, %1" : "=r"(fflags) : "r"(sticky));
+	return fflags;
+}
+DEF_WEAK(fpsetsticky);