mesa/gallium: Move u_bit_scan{,64} from gallium to util.

The functions are also useful for mesa.
Introduce src/util/bitscan.{h,c}. Move ffs function
implementations from src/mesa/main/imports.{h,c}.
Move bit scan related functions from
src/gallium/auxiliary/util/u_math.h. Merge platform
handling with what is available from within mesa.

v2: Try to fix MSVC compile.

Reviewed-by: Brian Paul <[email protected]>
Tested-by: Brian Paul <[email protected]>
Signed-off-by: Mathias Fröhlich <[email protected]>

1 files changed, 80 insertions, 0 deletions

diff --git a/src/util/bitscan.c b/src/util/bitscan.c
new file mode 100644
index 00000000000..ceca59eba98
--- /dev/null
+++ b/src/util/bitscan.c
@@ -0,0 +1,80 @@
+/**************************************************************************
+ *
+ * Copyright 2008 VMware, Inc.
+ * All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sub license, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial portions
+ * of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
+ * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
+ * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ **************************************************************************/
+
+
+#include "bitscan.h"
+
+#ifdef HAVE___BUILTIN_FFS
+#elif defined(_MSC_VER) && (_M_IX86 || _M_ARM || _M_AMD64 || _M_IA64)
+#else
+int
+ffs(unsigned i)
+{
+   int bit = 0;
+   if (!i)
+      return bit;
+   if (!(i & 0xffff)) {
+      bit += 16;
+      i >>= 16;
+   }
+   if (!(i & 0xff)) {
+      bit += 8;
+      i >>= 8;
+   }
+   if (!(i & 0xf)) {
+      bit += 4;
+      i >>= 4;
+   }
+   if (!(i & 0x3)) {
+      bit += 2;
+      i >>= 2;
+   }
+   if (!(i & 0x1))
+      bit += 1;
+   return bit + 1;
+}
+#endif
+
+#ifdef HAVE___BUILTIN_FFSLL
+#elif defined(_MSC_VER) && (_M_AMD64 || _M_ARM || _M_IA64)
+#else
+int
+ffsll(uint64_t val)
+{
+   int bit;
+
+   bit = ffs((unsigned) (val & 0xffffffff));
+   if (bit != 0)
+      return bit;
+
+   bit = ffs((unsigned) (val >> 32));
+   if (bit != 0)
+      return 32 + bit;
+
+   return 0;
+}
+#endif