From: Kevin Kirspel <kevin-kirspel@idexx.com>
To: <newlib@sourceware.org>
Cc: Kevin Kirspel <kevin-kirspel@idexx.com>
Subject: [PATCH v2] For RTEMS-LIBBSD support, add bitcount routines
Date: Wed, 17 May 2017 13:06:00 -0000 [thread overview]
Message-ID: <201705171306.v4HD3IpM000428@mx0a-00116901.pphosted.com> (raw)
---
newlib/libc/sys/rtems/include/machine/types.h | 58 +++++++++++++++++++++++++++
1 file changed, 58 insertions(+)
diff --git a/newlib/libc/sys/rtems/include/machine/types.h b/newlib/libc/sys/rtems/include/machine/types.h
index b28f923..0b0a100 100644
--- a/newlib/libc/sys/rtems/include/machine/types.h
+++ b/newlib/libc/sys/rtems/include/machine/types.h
@@ -83,3 +83,61 @@ typedef __uintmax_t rman_res_t;
#endif
#endif /* __BSD_VISIBLE */
+
+#ifdef __POPCNT__
+#define __bitcount64(x) __builtin_popcountll((__uint64_t)(x))
+#define __bitcount32(x) __builtin_popcount((__uint32_t)(x))
+#define __bitcount16(x) __builtin_popcount((__uint16_t)(x))
+#define __bitcountl(x) __builtin_popcountl((unsigned long)(x))
+#define __bitcount(x) __builtin_popcount((unsigned int)(x))
+#else /* __POPCNT__ */
+/*
+ * Population count algorithm using SWAR approach
+ * - "SIMD Within A Register".
+ */
+static __inline __uint16_t
+__bitcount16(__uint16_t _x)
+{
+ _x = (_x & 0x5555) + ((_x & 0xaaaa) >> 1);
+ _x = (_x & 0x3333) + ((_x & 0xcccc) >> 2);
+ _x = (_x + (_x >> 4)) & 0x0f0f;
+ _x = (_x + (_x >> 8)) & 0x00ff;
+ return (_x);
+}
+
+static __inline __uint32_t
+__bitcount32(__uint32_t _x)
+{
+ _x = (_x & 0x55555555) + ((_x & 0xaaaaaaaa) >> 1);
+ _x = (_x & 0x33333333) + ((_x & 0xcccccccc) >> 2);
+ _x = (_x + (_x >> 4)) & 0x0f0f0f0f;
+ _x = (_x + (_x >> 8));
+ _x = (_x + (_x >> 16)) & 0x000000ff;
+ return (_x);
+}
+
+#if __SIZEOF_INT__ == 8
+static __inline __uint64_t
+__bitcount64(__uint64_t _x)
+{
+ _x = (_x & 0x5555555555555555) + ((_x & 0xaaaaaaaaaaaaaaaa) >> 1);
+ _x = (_x & 0x3333333333333333) + ((_x & 0xcccccccccccccccc) >> 2);
+ _x = (_x + (_x >> 4)) & 0x0f0f0f0f0f0f0f0f;
+ _x = (_x + (_x >> 8));
+ _x = (_x + (_x >> 16));
+ _x = (_x + (_x >> 32)) & 0x000000ff;
+ return (_x);
+}
+
+#define __bitcountl(x) __bitcount64((unsigned long)(x))
+#else /* __SIZEOF_INT__ == 8 */
+static __inline __uint64_t
+__bitcount64(__uint64_t _x)
+{
+ return (__bitcount32(_x >> 32) + __bitcount32(_x));
+}
+
+#define __bitcountl(x) __bitcount32((unsigned long)(x))
+#endif /* __SIZEOF_INT__ == 8 */
+#define __bitcount(x) __bitcount32((unsigned int)(x))
+#endif /* __POPCNT__ */
--
1.9.1
next reply other threads:[~2017-05-17 13:06 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-17 13:06 Kevin Kirspel [this message]
2017-05-19 5:52 ` Sebastian Huber
2017-05-22 6:39 ` Sebastian Huber
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