[Minios-devel] [UNIKRAFT PATCH v2 3/9] include/uk: import bitcount.h

[Yuri Volchkov <yuri.volchkov@xxxxxxxxx>]

From: Costin Lupu <costin.lupu@xxxxxxxxx>

The definitions in this file are currently present in FreeBSD in the
sys/sys/types.h file with a comment stating that the definitions should
be elsewhere. The same definitions can be found in newlib v2.5.0 in
libc/sys/rtems/include/machine/_bitcount.h which we chose to port in
Unikraft. The original file was slightly adapted to use Unikraft include
guards and types.

Signed-off-by: Costin Lupu <costin.lupu@xxxxxxxxx>
Reviewed-by: Yuri Volchkov <yuri.volchkov@xxxxxxxxx>
---
 include/uk/bitcount.h | 91 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 91 insertions(+)
 create mode 100644 include/uk/bitcount.h

diff --git a/include/uk/bitcount.h b/include/uk/bitcount.h
new file mode 100644
index 0000000..60c19e9
--- /dev/null
+++ b/include/uk/bitcount.h
@@ -0,0 +1,91 @@
+/* SPDX-License-Identifier: BSD-3-Clause */
+/*-
+ * Copyright (c) 2015 John Baldwin <jhb@xxxxxxxxxxx>.
+ * 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.
+ * 3. Neither the name of the author nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
+ */
+
+#ifndef __UK_BITCOUNT_H__
+#define __UK_BITCOUNT_H__
+
+#ifdef __POPCNT__
+#define        uk_bitcount64(x)        __builtin_popcountll((__u64)(x))
+#define        uk_bitcount32(x)        __builtin_popcountl((__u32)(x))
+#define        uk_bitcount16(x)        __builtin_popcount((__u16)(x))
+#define        uk_bitcountl(x) __builtin_popcountl((unsigned long)(x))
+#define        uk_bitcount(x)  __builtin_popcount((unsigned int)(x))
+#else /* !__POPCNT__ */
+static inline __u16
+uk_bitcount16(__u16 _x)
+{
+       _x = (_x & 0x5555u) + ((_x & 0xaaaau) >> 1);
+       _x = (_x & 0x3333u) + ((_x & 0xccccu) >> 2);
+       _x = (_x + (_x >> 4)) & 0x0f0fu;
+       _x = (_x + (_x >> 8)) & 0x00ffu;
+       return _x;
+}
+
+static inline __u32
+uk_bitcount32(__u32 _x)
+{
+       _x = (_x & 0x55555555u) + ((_x & 0xaaaaaaaau) >> 1);
+       _x = (_x & 0x33333333u) + ((_x & 0xccccccccu) >> 2);
+       _x = (_x + (_x >> 4)) & 0x0f0f0f0fu;
+       _x = (_x + (_x >> 8));
+       _x = (_x + (_x >> 16)) & 0x000000ffu;
+       return _x;
+}
+
+static inline __u64
+uk_bitcount64(__u64 _x)
+{
+#if __SIZEOF_LONG__ == 8
+       _x = (_x & 0x5555555555555555u) + ((_x & 0xaaaaaaaaaaaaaaaau) >> 1);
+       _x = (_x & 0x3333333333333333u) + ((_x & 0xccccccccccccccccu) >> 2);
+       _x = (_x + (_x >> 4)) & 0x0f0f0f0f0f0f0f0fu;
+       _x = (_x + (_x >> 8));
+       _x = (_x + (_x >> 16));
+       _x = (_x + (_x >> 32)) & 0x000000ffu;
+       return _x;
+#else
+       return (uk_bitcount32(_x >> 32) + uk_bitcount32(_x));
+#endif
+}
+
+#if __SIZEOF_LONG__ == 8
+#define        uk_bitcountl(x) uk_bitcount64((unsigned long)(x))
+#else
+#define        uk_bitcountl(x) uk_bitcount32((unsigned long)(x))
+#endif
+
+#if __SIZEOF_INT__ == 8
+#define        uk_bitcount(x)  uk_bitcount64((unsigned int)(x))
+#else
+#define        uk_bitcount(x)  uk_bitcount32((unsigned int)(x))
+#endif
+#endif /* __POPCNT__ */
+
+#endif /* __UK_BITCOUNT_H__ */
-- 
2.18.0


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