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]>

6 files changed, 237 insertions, 222 deletions

diff --git a/src/gallium/auxiliary/util/u_math.h b/src/gallium/auxiliary/util/u_math.h
index ecb1d636fcc..c94967e8a42 100644
--- a/src/gallium/auxiliary/util/u_math.h
+++ b/src/gallium/auxiliary/util/u_math.h
@@ -46,14 +46,7 @@
 #include <float.h>
 #include <stdarg.h>
 
-#ifdef PIPE_OS_UNIX
-#include <strings.h> /* for ffs */
-#endif
-
-#if defined(_MSC_VER)
-#include <intrin.h>
-#endif
-
+#include "util/bitscan.h"
 
 #ifdef __cplusplus
 extern "C" {
@@ -354,80 +347,6 @@ util_half_inf_sign(int16_t x)
 
 
 /**
- * Find first bit set in word.  Least significant bit is 1.
- * Return 0 if no bits set.
- */
-#ifndef FFS_DEFINED
-#define FFS_DEFINED 1
-
-#if defined(_MSC_VER) && (_M_IX86 || _M_AMD64 || _M_IA64)
-static inline
-unsigned long ffs( unsigned long u )
-{
-   unsigned long i;
-   if (_BitScanForward(&i, u))
-      return i + 1;
-   else
-      return 0;
-}
-#elif defined(PIPE_CC_MSVC) && defined(PIPE_ARCH_X86)
-static inline
-unsigned ffs( unsigned u )
-{
-   unsigned i;
-
-   if (u == 0) {
-      return 0;
-   }
-
-   __asm bsf eax, [u]
-   __asm inc eax
-   __asm mov [i], eax
-
-   return i;
-}
-#elif defined(__MINGW32__) || defined(PIPE_OS_ANDROID) || \
-    defined(HAVE___BUILTIN_FFS)
-#define ffs __builtin_ffs
-#endif
-
-#ifdef HAVE___BUILTIN_FFSLL
-#define ffsll __builtin_ffsll
-#else
-static inline int
-ffsll(long long int 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
-
-#endif /* FFS_DEFINED */
-
-/**
- * Find first bit set in long long.  Least significant bit is 1.
- * Return 0 if no bits set.
- */
-#ifndef FFSLL_DEFINED
-#define FFSLL_DEFINED 1
-
-#if defined(__MINGW32__) || defined(PIPE_OS_ANDROID) || \
-    defined(HAVE___BUILTIN_FFSLL)
-#define ffsll __builtin_ffsll
-#endif
-
-#endif /* FFSLL_DEFINED */
-
-/**
  * Find last bit set in a word.  The least significant bit is 1.
  * Return 0 if no bits are set.
  */
@@ -479,72 +398,6 @@ util_last_bit_signed(int i)
       return util_last_bit(~(unsigned)i);
 }
 
-/* Destructively loop over all of the bits in a mask as in:
- *
- * while (mymask) {
- *   int i = u_bit_scan(&mymask);
- *   ... process element i
- * }
- *
- */
-static inline int
-u_bit_scan(unsigned *mask)
-{
-   int i = ffs(*mask) - 1;
-   *mask &= ~(1u << i);
-   return i;
-}
-
-#ifndef _MSC_VER
-static inline int
-u_bit_scan64(uint64_t *mask)
-{
-   int i = ffsll(*mask) - 1;
-   *mask &= ~(1llu << i);
-   return i;
-}
-#endif
-
-/* For looping over a bitmask when you want to loop over consecutive bits
- * manually, for example:
- *
- * while (mask) {
- *    int start, count, i;
- *
- *    u_bit_scan_consecutive_range(&mask, &start, &count);
- *
- *    for (i = 0; i < count; i++)
- *       ... process element (start+i)
- * }
- */
-static inline void
-u_bit_scan_consecutive_range(unsigned *mask, int *start, int *count)
-{
-   if (*mask == 0xffffffff) {
-      *start = 0;
-      *count = 32;
-      *mask = 0;
-      return;
-   }
-   *start = ffs(*mask) - 1;
-   *count = ffs(~(*mask >> *start)) - 1;
-   *mask &= ~(((1u << *count) - 1) << *start);
-}
-
-static inline void
-u_bit_scan_consecutive_range64(uint64_t *mask, int *start, int *count)
-{
-   if (*mask == ~0llu) {
-      *start = 0;
-      *count = 64;
-      *mask = 0;
-      return;
-   }
-   *start = ffsll(*mask) - 1;
-   *count = ffsll(~(*mask >> *start)) - 1;
-   *mask &= ~(((1llu << *count) - 1) << *start);
-}
-
 /* Returns a bitfield in which the first count bits starting at start are
  * set.
  */
diff --git a/src/mesa/main/imports.c b/src/mesa/main/imports.c
index fe54109322d..808b8f67302 100644
--- a/src/mesa/main/imports.c
+++ b/src/mesa/main/imports.c
@@ -219,64 +219,6 @@ _mesa_align_realloc(void *oldBuffer, size_t oldSize, size_t newSize,
 /*@{*/
 
 
-#ifndef HAVE___BUILTIN_FFS
-/**
- * Find the first bit set in a word.
- */
-int
-ffs(int i)
-{
-   register int bit = 0;
-   if (i != 0) {
-      if ((i & 0xffff) == 0) {
-         bit += 16;
-         i >>= 16;
-      }
-      if ((i & 0xff) == 0) {
-         bit += 8;
-         i >>= 8;
-      }
-      if ((i & 0xf) == 0) {
-         bit += 4;
-         i >>= 4;
-      }
-      while ((i & 1) == 0) {
-         bit++;
-         i >>= 1;
-      }
-      bit++;
-   }
-   return bit;
-}
-#endif
-
-#ifndef HAVE___BUILTIN_FFSLL
-/**
- * Find position of first bit set in given value.
- * XXX Warning: this function can only be used on 64-bit systems!
- * \return  position of least-significant bit set, starting at 1, return zero
- *          if no bits set.
- */
-int
-ffsll(long long int val)
-{
-   int bit;
-
-   STATIC_ASSERT(sizeof(val) == 8);
-
-   bit = ffs((int) val);
-   if (bit != 0)
-      return bit;
-
-   bit = ffs((int) (val >> 32));
-   if (bit != 0)
-      return 32 + bit;
-
-   return 0;
-}
-#endif
-
-
 #ifndef HAVE___BUILTIN_POPCOUNT
 /**
  * Return number of bits set in given GLuint.
diff --git a/src/mesa/main/imports.h b/src/mesa/main/imports.h
index d96d666e15f..4ff5941487f 100644
--- a/src/mesa/main/imports.h
+++ b/src/mesa/main/imports.h
@@ -42,6 +42,7 @@
 #include "compiler.h"
 #include "glheader.h"
 #include "errors.h"
+#include "util/bitscan.h"
 
 #ifdef __cplusplus
 extern "C" {
@@ -324,22 +325,6 @@ extern void
 _mesa_exec_free( void *addr );
 
 
-#ifndef FFS_DEFINED
-#define FFS_DEFINED 1
-#ifdef HAVE___BUILTIN_FFS
-#define ffs __builtin_ffs
-#else
-extern int ffs(int i);
-#endif
-
-#ifdef HAVE___BUILTIN_FFSLL
-#define ffsll __builtin_ffsll
-#else
-extern int ffsll(long long int i);
-#endif
-#endif /* FFS_DEFINED */
-
-
 #ifdef HAVE___BUILTIN_POPCOUNT
 #define _mesa_bitcount(i) __builtin_popcount(i)
 #else
diff --git a/src/util/Makefile.sources b/src/util/Makefile.sources
index a87114601c8..aec41c389ea 100644
--- a/src/util/Makefile.sources
+++ b/src/util/Makefile.sources
@@ -1,4 +1,6 @@
 MESA_UTIL_FILES :=	\
+	bitscan.c \
+	bitscan.h \
 	bitset.h \
 	debug.c \
 	debug.h \
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
diff --git a/src/util/bitscan.h b/src/util/bitscan.h
new file mode 100644
index 00000000000..4999b744d1d
--- /dev/null
+++ b/src/util/bitscan.h
@@ -0,0 +1,153 @@
+/**************************************************************************
+ *
+ * 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.
+ *
+ **************************************************************************/
+
+
+#ifndef BITSCAN_H
+#define BITSCAN_H
+
+#include <stdint.h>
+
+#if defined(_MSC_VER)
+#include <intrin.h>
+#endif
+
+#include "c99_compat.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+
+/**
+ * Find first bit set in word.  Least significant bit is 1.
+ * Return 0 if no bits set.
+ */
+#ifdef HAVE___BUILTIN_FFS
+#define ffs __builtin_ffs
+#elif defined(_MSC_VER) && (_M_IX86 || _M_ARM || _M_AMD64 || _M_IA64)
+static inline
+int ffs(unsigned i)
+{
+   unsigned long index;
+   if (_BitScanForward(&index, i))
+      return index + 1;
+   else
+      return 0;
+}
+#else
+extern
+int ffs(unsigned i);
+#endif
+
+#ifdef HAVE___BUILTIN_FFSLL
+#define ffsll __builtin_ffsll
+#elif defined(_MSC_VER) && (_M_AMD64 || _M_ARM || _M_IA64)
+static inline int
+ffsll(uint64_t i)
+{
+   unsigned long index;
+   if (_BitScanForward64(&index, i))
+      return index + 1;
+   else
+      return 0;
+}
+#else
+extern int
+ffsll(uint64_t val);
+#endif
+
+
+/* Destructively loop over all of the bits in a mask as in:
+ *
+ * while (mymask) {
+ *   int i = u_bit_scan(&mymask);
+ *   ... process element i
+ * }
+ *
+ */
+static inline int
+u_bit_scan(unsigned *mask)
+{
+   const int i = ffs(*mask) - 1;
+   *mask ^= (1u << i);
+   return i;
+}
+
+static inline int
+u_bit_scan64(uint64_t *mask)
+{
+   const int i = ffsll(*mask) - 1;
+   *mask ^= (((uint64_t)1) << i);
+   return i;
+}
+
+/* For looping over a bitmask when you want to loop over consecutive bits
+ * manually, for example:
+ *
+ * while (mask) {
+ *    int start, count, i;
+ *
+ *    u_bit_scan_consecutive_range(&mask, &start, &count);
+ *
+ *    for (i = 0; i < count; i++)
+ *       ... process element (start+i)
+ * }
+ */
+static inline void
+u_bit_scan_consecutive_range(unsigned *mask, int *start, int *count)
+{
+   if (*mask == 0xffffffff) {
+      *start = 0;
+      *count = 32;
+      *mask = 0;
+      return;
+   }
+   *start = ffs(*mask) - 1;
+   *count = ffs(~(*mask >> *start)) - 1;
+   *mask &= ~(((1u << *count) - 1) << *start);
+}
+
+static inline void
+u_bit_scan_consecutive_range64(uint64_t *mask, int *start, int *count)
+{
+   if (*mask == ~0llu) {
+      *start = 0;
+      *count = 64;
+      *mask = 0;
+      return;
+   }
+   *start = ffsll(*mask) - 1;
+   *count = ffsll(~(*mask >> *start)) - 1;
+   *mask &= ~(((((uint64_t)1) << *count) - 1) << *start);
+}
+
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* BITSCAN_H */