[PATCH] For RTEMS-LIBBSD support, add bitcount routines

[Kevin Kirspel <kevin-kirspel at idexx dot com>]

---
 newlib/libc/include/sys/types.h | 66 ++++++++++++++++++++++++++++++++++++++---
 1 file changed, 62 insertions(+), 4 deletions(-)

diff --git a/newlib/libc/include/sys/types.h b/newlib/libc/include/sys/types.h
index 65ff520..83f891e 100644
--- a/newlib/libc/include/sys/types.h
+++ b/newlib/libc/include/sys/types.h
@@ -53,6 +53,64 @@ typedef	__int64_t	quad_t;
 typedef	quad_t *	qaddr_t;
 #endif

+#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);
+}
+
+#ifdef __LP64__
+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 /* __LP64__ */
+static __inline __uint64_t
+__bitcount64(__uint64_t _x)
+{
+	return (__bitcount32(_x >> 32) + __bitcount32(_x));
+}
+
+#define __bitcountl(x)  __bitcount32((unsigned long)(x))
+#endif /* __LP64__ */
+#define __bitcount(x)   __bitcount32((unsigned int)(x))
+#endif /* __POPCNT__ */
+
 #endif /* __rtems__ || __XMK__ */

 #ifndef __need_inttypes
--
1.9.1