/*
* Copyright (c) 2010 Mans Rullgard <mans@mansr.com>
*
- * This file is part of FFmpeg.
+ * This file is part of Libav.
*
- * FFmpeg is free software; you can redistribute it and/or
+ * Libav is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
- * FFmpeg is distributed in the hope that it will be useful,
+ * Libav is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
- * License along with FFmpeg; if not, write to the Free Software
+ * License along with Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#define AVUTIL_INTMATH_H
#include <stdint.h>
+
#include "config.h"
#include "attributes.h"
-extern const uint32_t ff_inverse[257];
-
-#if ARCH_ARM
+#if ARCH_ARM
# include "arm/intmath.h"
-#elif ARCH_X86
-# include "x86/intmath.h"
#endif
+/**
+ * @addtogroup lavu_internal
+ * @{
+ */
+
#if HAVE_FAST_CLZ && AV_GCC_VERSION_AT_LEAST(3,4)
-#ifndef av_log2
+#ifndef ff_log2
+# define ff_log2(x) (31 - __builtin_clz((x)|1))
+# ifndef ff_log2_16bit
+# define ff_log2_16bit av_log2
+# endif
+#endif /* ff_log2 */
-#define av_log2(x) (31 - __builtin_clz((x)|1))
+#endif /* AV_GCC_VERSION_AT_LEAST(3,4) */
-#ifndef av_log2_16bit
-#define av_log2_16bit av_log2
-#endif
+extern const uint8_t ff_log2_tab[256];
-#endif /* av_log2 */
+#ifndef ff_log2
+#define ff_log2 ff_log2_c
+static av_always_inline av_const int ff_log2_c(unsigned int v)
+{
+ int n = 0;
+ if (v & 0xffff0000) {
+ v >>= 16;
+ n += 16;
+ }
+ if (v & 0xff00) {
+ v >>= 8;
+ n += 8;
+ }
+ n += ff_log2_tab[v];
-#endif /* AV_GCC_VERSION_AT_LEAST(3,4) */
+ return n;
+}
+#endif
-#ifndef FASTDIV
+#ifndef ff_log2_16bit
+#define ff_log2_16bit ff_log2_16bit_c
+static av_always_inline av_const int ff_log2_16bit_c(unsigned int v)
+{
+ int n = 0;
+ if (v & 0xff00) {
+ v >>= 8;
+ n += 8;
+ }
+ n += ff_log2_tab[v];
-#if CONFIG_FASTDIV
-# define FASTDIV(a,b) ((uint32_t)((((uint64_t)a) * ff_inverse[b]) >> 32))
-#else
-# define FASTDIV(a,b) ((a) / (b))
+ return n;
+}
#endif
-#endif /* FASTDIV */
+#define av_log2 ff_log2
+#define av_log2_16bit ff_log2_16bit
-/*
- * Get definition of av_log2_c from common.h. In the event we got
- * here through common.h including this file, including it again will
- * be a no-op due to multi-inclusion guards, so we must duplicate the
- * fallback defines here.
+/**
+ * @}
*/
-#include "common.h"
+/**
+ * @addtogroup lavu_math
+ * @{
+ */
-#ifndef av_log2
-# define av_log2 av_log2_c
+#if HAVE_FAST_CLZ && AV_GCC_VERSION_AT_LEAST(3,4)
+#ifndef ff_ctz
+#define ff_ctz(v) __builtin_ctz(v)
#endif
-#ifndef av_log2_16bit
-# define av_log2_16bit av_log2_16bit_c
#endif
-extern const uint8_t ff_sqrt_tab[256];
-
-static inline av_const unsigned int ff_sqrt(unsigned int a)
+#ifndef ff_ctz
+#define ff_ctz ff_ctz_c
+static av_always_inline av_const int ff_ctz_c(int v)
{
- unsigned int b;
+ int c;
- if (a < 255) return (ff_sqrt_tab[a + 1] - 1) >> 4;
- else if (a < (1 << 12)) b = ff_sqrt_tab[a >> 4] >> 2;
-#if !CONFIG_SMALL
- else if (a < (1 << 14)) b = ff_sqrt_tab[a >> 6] >> 1;
- else if (a < (1 << 16)) b = ff_sqrt_tab[a >> 8] ;
-#endif
- else {
- int s = av_log2_16bit(a >> 16) >> 1;
- unsigned int c = a >> (s + 2);
- b = ff_sqrt_tab[c >> (s + 8)];
- b = FASTDIV(c,b) + (b << s);
+ if (v & 0x1)
+ return 0;
+
+ c = 1;
+ if (!(v & 0xffff)) {
+ v >>= 16;
+ c += 16;
+ }
+ if (!(v & 0xff)) {
+ v >>= 8;
+ c += 8;
}
+ if (!(v & 0xf)) {
+ v >>= 4;
+ c += 4;
+ }
+ if (!(v & 0x3)) {
+ v >>= 2;
+ c += 2;
+ }
+ c -= v & 0x1;
- return b - (a < b * b);
+ return c;
}
+#endif
+/**
+ * Trailing zero bit count.
+ *
+ * @param v input value. If v is 0, the result is undefined.
+ * @return the number of trailing 0-bits
+ */
+int av_ctz(int v);
+
+/**
+ * @}
+ */
#endif /* AVUTIL_INTMATH_H */