From: Pyry Haulos <phaulos@google.com>
Date: Wed, 30 Sep 2015 17:56:36 +0000 (-0700)
Subject: Add deCtz32() to deInt32.h
X-Git-Tag: upstream/0.1.0~1375^2
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=cb805b527ba47805a898053ebc4df1b3acfc9963;p=platform%2Fupstream%2FVK-GL-CTS.git

Add deCtz32() to deInt32.h

deCtz32() computes number of trailing zeros.

Change-Id: I44707d92696af927d7464b75be789571338be479
---

diff --git a/framework/delibs/debase/deInt32.c b/framework/delibs/debase/deInt32.c
index 6905108..80dd150 100644
--- a/framework/delibs/debase/deInt32.c
+++ b/framework/delibs/debase/deInt32.c
@@ -45,6 +45,26 @@ const deInt8 g_clzLUT[256] =
 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
 };
 
+const deInt8 g_ctzLUT[256] =
+{
+	8, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
+	4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
+	5, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
+	4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
+	6, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
+	4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
+	5, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
+	4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
+	7, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
+	4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
+	5, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
+	4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
+	6, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
+	4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
+	5, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
+	4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0
+};
+
 /*--------------------------------------------------------------------*//*!
  * \brief Compute the reciprocal of an integer.
  * \param a		Input value.
diff --git a/framework/delibs/debase/deInt32.h b/framework/delibs/debase/deInt32.h
index 6e574e5..c1b4887 100644
--- a/framework/delibs/debase/deInt32.h
+++ b/framework/delibs/debase/deInt32.h
@@ -254,13 +254,13 @@ DE_INLINE void* deAlignPtr (void* ptr, deUintptr align)
 	return (void*)((val + align - 1) & ~(align - 1));
 }
 
+extern const deInt8 g_clzLUT[256];
+
 /*--------------------------------------------------------------------*//*!
  * \brief Compute number of leading zeros in an integer.
  * \param a	Input value.
  * \return The number of leading zero bits in the input.
  *//*--------------------------------------------------------------------*/
-extern const deInt8 g_clzLUT[256];
-
 DE_INLINE int deClz32 (deUint32 a)
 {
 #if (DE_COMPILER == DE_COMPILER_MSC)
@@ -285,6 +285,37 @@ DE_INLINE int deClz32 (deUint32 a)
 #endif
 }
 
+extern const deInt8 g_ctzLUT[256];
+
+/*--------------------------------------------------------------------*//*!
+ * \brief Compute number of trailing zeros in an integer.
+ * \param a	Input value.
+ * \return The number of trailing zero bits in the input.
+ *//*--------------------------------------------------------------------*/
+DE_INLINE int deCtz32 (deUint32 a)
+{
+#if (DE_COMPILER == DE_COMPILER_MSC)
+	unsigned long i;
+	if (_BitScanForward(&i, (unsigned long)a) == 0)
+		return 32;
+	else
+		return i;
+#elif (DE_COMPILER == DE_COMPILER_GCC) || (DE_COMPILER == DE_COMPILER_CLANG)
+	if (a == 0)
+		return 32;
+	else
+		return __builtin_ctz((unsigned int)a);
+#else
+	if ((a & 0x00FFFFFFu) == 0)
+		return (int)g_ctzLUT[a >> 24] + 24;
+	if ((a & 0x0000FFFFu) == 0)
+		return (int)g_ctzLUT[(a >> 16) & 0xffu] + 16;
+	if ((a & 0x000000FFu) == 0)
+		return (int)g_ctzLUT[(a >> 8) & 0xffu] + 8;
+	return (int)g_ctzLUT[a & 0xffu];
+#endif
+}
+
 /*--------------------------------------------------------------------*//*!
  * \brief Compute integer 'floor' of 'log2' for a positive integer.
  * \param a	Input value.
diff --git a/framework/delibs/debase/deInt32Test.c b/framework/delibs/debase/deInt32Test.c
index 9d3d29a..d87aee7 100644
--- a/framework/delibs/debase/deInt32Test.c
+++ b/framework/delibs/debase/deInt32Test.c
@@ -76,6 +76,15 @@ void deInt32_selfTest (void)
 	deRandom_init(&rnd, 0xdeadbeefu-1);
 
 	/* Test deClz32(). */
+	{
+		int i;
+		for (i = 0; i < 32; i++)
+		{
+			DE_TEST_ASSERT(deClz32(1u << i) == 31-i);
+			DE_TEST_ASSERT(deClz32((1u << i) | ((1u << i)-1u)) == 31-i);
+		}
+	}
+
 	DE_TEST_ASSERT(deClz32(0) == 32);
 	DE_TEST_ASSERT(deClz32(1) == 31);
 	DE_TEST_ASSERT(deClz32(0xF1) == 24);
@@ -86,6 +95,22 @@ void deInt32_selfTest (void)
 	DE_TEST_ASSERT(deClz32(0x40000000) == 1);
 	DE_TEST_ASSERT(deClz32(0x80000000) == 0);
 
+	/* Test deCtz32(). */
+	{
+		int i;
+		for (i = 0; i < 32; i++)
+		{
+			DE_TEST_ASSERT(deCtz32(1u << i) == i);
+			DE_TEST_ASSERT(deCtz32(~((1u << i)-1u)) == i);
+		}
+	}
+
+	DE_TEST_ASSERT(deCtz32(0) == 32);
+	DE_TEST_ASSERT(deCtz32(1) == 0);
+	DE_TEST_ASSERT(deCtz32(0x3F4) == 2);
+	DE_TEST_ASSERT(deCtz32(0x3F40) == 6);
+	DE_TEST_ASSERT(deCtz32(0xFFFFFFFF) == 0);
+
 	/* Test simple inputs for dePop32(). */
 	DE_TEST_ASSERT(dePop32(0u) == 0);
 	DE_TEST_ASSERT(dePop32(~0u) == 32);