ircd::simd: Add lower()/upper() templates for splitting.

include/ircd/simd/lower.h

@@ -0,0 +1,44 @@
+// The Construct
+//
+// Copyright (C) The Construct Developers, Authors & Contributors
+// Copyright (C) 2016-2020 Jason Volk <jason@zemos.net>
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice is present in all copies. The
+// full license for this software is available in the LICENSE file.
+
+#pragma once
+#define HAVE_IRCD_SIMD_LOWER_H
+
+namespace ircd::simd
+{
+	template<class R,
+	         class T>
+	R lower(const T) noexcept;
+}
+
+template<class R,
+         class T>
+inline R
+ircd::simd::lower(const T a)
+noexcept
+{
+	static_assert
+	(
+		sizeof(R) * 2 == sizeof(T),
+		"Types must have equal size."
+	);
+
+	static_assert
+	(
+		lanes<R>() * 2 == lanes<T>(),
+		"T must have twice as many lanes as R"
+	);
+
+	R ret;
+	for(size_t i(0); i < lanes<R>(); ++i)
+		ret[i] = a[i];
+
+	return ret;
+}

include/ircd/simd/simd.h

@@ -16,6 +16,9 @@
 #include "traits.h"
 #include "lane_cast.h"
 #include "broad_cast.h"
+#include "split.h"
+#include "lower.h"
+#include "upper.h"
 #include "shift.h"
 #include "popcnt.h"
 #include "lzcnt.h"

include/ircd/simd/split.h

@@ -0,0 +1,45 @@
+// The Construct
+//
+// Copyright (C) The Construct Developers, Authors & Contributors
+// Copyright (C) 2016-2020 Jason Volk <jason@zemos.net>
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice is present in all copies. The
+// full license for this software is available in the LICENSE file.
+
+#pragma once
+#define HAVE_IRCD_SIMD_SPLIT_H
+
+namespace ircd::simd
+{
+	template<class R,
+	         class T>
+	std::array<R, 2> split(const T) noexcept;
+}
+
+template<class R,
+         class T>
+inline std::array<R, 2>
+ircd::simd::split(const T a)
+noexcept
+{
+	static_assert
+	(
+		sizeof(R) * 2 == sizeof(T),
+		"Types must have equal size."
+	);
+
+	static_assert
+	(
+		lanes<R>() * 2 == lanes<T>(),
+		"T must have twice as many lanes as R"
+	);
+
+	std::array<R, 2> ret;
+	for(size_t i(0); i < lanes<R>(); ++i)
+		ret[0][i] = a[i],
+		ret[1][i] = a[lanes<R>() + i];
+
+	return ret;
+}

include/ircd/simd/upper.h

@@ -0,0 +1,44 @@
+// The Construct
+//
+// Copyright (C) The Construct Developers, Authors & Contributors
+// Copyright (C) 2016-2020 Jason Volk <jason@zemos.net>
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice is present in all copies. The
+// full license for this software is available in the LICENSE file.
+
+#pragma once
+#define HAVE_IRCD_SIMD_UPPER_H
+
+namespace ircd::simd
+{
+	template<class R,
+	         class T>
+	R upper(const T) noexcept;
+}
+
+template<class R,
+         class T>
+inline R
+ircd::simd::upper(const T a)
+noexcept
+{
+	static_assert
+	(
+		sizeof(R) * 2 == sizeof(T),
+		"Types must have equal size."
+	);
+
+	static_assert
+	(
+		lanes<R>() * 2 == lanes<T>(),
+		"T must have twice as many lanes as R"
+	);
+
+	R ret;
+	for(size_t i(0); i < lanes<R>(); ++i)
+		ret[i] = a[lanes<R>() + i];
+
+	return ret;
+}