添加信息

applications/drv/memheap_alloc_align.c

@@ -0,0 +1,59 @@
+#include <rtthread.h>
+#include <rthw.h>
+
+/**
+ * @brief Allocate aligned memory from a memheap
+ *
+ * @param heap    Pointer to the memheap object
+ * @param size    Requested user memory size (in bytes)
+ * @param align   Alignment boundary (must be power of 2, e.g., 4, 8, 16)
+ * @return void*  Aligned pointer on success, RT_NULL on failure
+ *
+ * @note The returned pointer must be freed with rt_memheap_free_align()
+ */
+void *rt_memheap_alloc_align(struct rt_memheap *heap, rt_size_t size, rt_size_t align)
+{
+    void *raw_ptr;
+    void *aligned_ptr;
+    uintptr_t *header; // stores raw_ptr for free
+
+    RT_ASSERT(heap != RT_NULL);
+    RT_ASSERT(size > 0);
+    RT_ASSERT(align > 0 && (align & (align - 1)) == 0); // check power of 2
+
+    // Minimum space: user data + alignment padding + hidden header (sizeof(uintptr_t))
+    rt_size_t total_size = size + align - 1 + sizeof(uintptr_t);
+
+    raw_ptr = rt_memheap_alloc(heap, total_size);
+    if (raw_ptr == RT_NULL)
+        return RT_NULL;
+
+    // Calculate aligned address after hidden header
+    uintptr_t addr = (uintptr_t)raw_ptr + sizeof(uintptr_t);
+    aligned_ptr = (void *)((addr + align - 1) & ~(align - 1));
+
+    // Store raw_ptr just before aligned_ptr (in the hidden header)
+    header = (uintptr_t *)aligned_ptr - 1;
+    *header = (uintptr_t)raw_ptr;
+
+    return aligned_ptr;
+}
+
+/**
+ * @brief Free memory allocated by rt_memheap_alloc_align()
+ *
+ * @param heap   Pointer to the memheap object
+ * @param ptr    Pointer returned by rt_memheap_alloc_align()
+ */
+void rt_memheap_free_align(struct rt_memheap *heap, void *ptr)
+{
+    if (ptr == RT_NULL)
+        return;
+
+    // Retrieve raw_ptr from hidden header
+    uintptr_t *header = (uintptr_t *)ptr - 1;
+    void *raw_ptr = (void *)(*header);
+
+    rt_memheap_free(raw_ptr);
+}
+