From 18888679cd2008b8a5fbc3082f2e562f63c767b3 Mon Sep 17 00:00:00 2001
From: "bernard.xiong@gmail.com" <bernard.xiong@gmail.com>
Date: Mon, 30 Jan 2012 12:22:57 +0000
Subject: [PATCH] add alignment memory allocation.

git-svn-id: https://rt-thread.googlecode.com/svn/trunk@1928 bbd45198-f89e-11dd-88c7-29a3b14d5316
---
 include/rtdef.h    |  6 ++---
 include/rtthread.h |  2 ++
 src/kservice.c     | 58 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 63 insertions(+), 3 deletions(-)

diff --git a/include/rtdef.h b/include/rtdef.h
index 18055b8f90..0847db737d 100644
--- a/include/rtdef.h
+++ b/include/rtdef.h
@@ -30,9 +30,9 @@ extern "C" {
  */
 /*@{*/
 
-/* RT-Thread version information */
+/* RT-Thread version information */
 #define RT_VERSION                      1L      /**< major version number */
-#define RT_SUBVERSION                   0L      /**< minor version number */
+#define RT_SUBVERSION                   1L      /**< minor version number */
 #define RT_REVISION                   	0L      /**< revise version number */
 
 /* RT-Thread basic data type definitions */
@@ -334,7 +334,7 @@ typedef struct rt_timer *rt_timer_t;
 /**
  * thread control command definitions
  */
-#define RT_THREAD_CTRL_STARTUP          0x00                /**< Starup thread.                     */
+#define RT_THREAD_CTRL_STARTUP          0x00                /**< Startup thread.                     */
 #define RT_THREAD_CTRL_CLOSE            0x01                /**< Close thread.                      */
 #define RT_THREAD_CTRL_CHANGE_PRIORITY  0x02                /**< Change thread priority.            */
 #define RT_THREAD_CTRL_INFO             0x03                /**< Get thread information.            */
diff --git a/include/rtthread.h b/include/rtthread.h
index eb7e2560a5..1cf0532627 100644
--- a/include/rtthread.h
+++ b/include/rtthread.h
@@ -179,6 +179,8 @@ void *rt_malloc(rt_size_t nbytes);
 void rt_free(void *ptr);
 void *rt_realloc(void *ptr, rt_size_t nbytes);
 void *rt_calloc(rt_size_t count, rt_size_t size);
+void* rt_malloc_align(rt_size_t size, rt_size_t align);
+void rt_free_align(void* ptr);
 
 void rt_memory_info(rt_uint32_t *total, rt_uint32_t *used, rt_uint32_t *max_used);
 
diff --git a/src/kservice.c b/src/kservice.c
index 14fb19b225..0a96de77c8 100644
--- a/src/kservice.c
+++ b/src/kservice.c
@@ -1042,6 +1042,64 @@ void rt_kprintf(const char *fmt, ...)
 }
 #endif
 
+#ifdef RT_USING_HEAP
+/**
+ * This function allocates a memory block, which address is aligned to the
+ * specified alignment size.
+ *
+ * @param size the allocated memory block size
+ * @param align the alignment size
+ *
+ * @return the allocated memory block on successful, otherwise returns RT_NULL
+ */
+void* rt_malloc_align(rt_size_t size, rt_size_t align)
+{
+	void *align_ptr;
+	void *ptr;
+	rt_size_t align_size;
+
+	/* align the alignment size to 4 byte */
+	align = ((align + 0x03) & ~0x03);
+
+	/* get total aligned size */
+	align_size = ((size + 0x03) & ~0x03) + align;
+	/* allocate memory block from heap */
+	ptr = rt_malloc(align_size);
+	if (ptr != RT_NULL)
+	{
+		if (((rt_uint32_t)ptr & (align - 1)) == 0) /* the allocated memory block is aligned */
+		{
+			align_ptr = (void*) ((rt_uint32_t)ptr + align);
+		}
+		else
+		{
+			align_ptr = (void*) (((rt_uint32_t)ptr + (align - 1)) & ~(align - 1));
+		}
+
+		/* set the pointer before alignment pointer to the real pointer */
+		*((rt_uint32_t*)((rt_uint32_t)align_ptr - sizeof(void*))) = (rt_uint32_t)ptr;
+
+		ptr = align_ptr;
+	}
+
+	return ptr;
+}
+
+/**
+ * This function release the memory block, which is allocated by rt_malloc_align
+ * function and address is aligned.
+ *
+ * @param ptr the memory block pointer
+ */
+void rt_free_align(void* ptr)
+{
+	void* real_ptr;
+
+	real_ptr = (void*)*(rt_uint32_t*)((rt_uint32_t)ptr - sizeof(void*));
+	rt_free(real_ptr);
+}
+#endif
+
 #if !defined (RT_USING_NEWLIB) && defined (RT_USING_MINILIBC) && defined (__GNUC__)
 #include <sys/types.h>
 void *memcpy(void *dest, const void *src, size_t n) __attribute__((weak, alias("rt_memcpy")));
-- 
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