+#include <sdcc-lib.h>
+#include <malloc.h>
+#if _SDCC_MALLOC_TYPE_MLH
+
+typedef struct _MEMHEADER MEMHEADER;
+
+struct _MEMHEADER
+{
+ MEMHEADER * next;
+ MEMHEADER * prev;
+ unsigned int len;
+ unsigned char mem;
+};
+
+#define HEADER_SIZE (sizeof(MEMHEADER)-sizeof(char))
+
+/* These variables are defined through the crt0 functions. */
+/* Base of this variable is the first byte of the heap. */
+extern MEMHEADER _sdcc_heap_start;
+/* Address of this variable is the last byte of the heap. */
+extern char _sdcc_heap_end;
+
+void
+_sdcc_heap_init(void)
+{
+ MEMHEADER *pbase = &_sdcc_heap_start;
+ unsigned int size = &_sdcc_heap_end - (char *)pbase;
+
+ pbase->next = (MEMHEADER *)((char *)pbase + size - HEADER_SIZE);
+ pbase->next->next = NULL; //And mark it as last
+ pbase->prev = NULL; //and mark first as first
+ pbase->len = 0; //Empty and ready.
+}
+
+void *
+malloc (unsigned int size)
+{
+ MEMHEADER * current_header;
+ MEMHEADER * new_header;
+
+ if (size>(0xFFFF-HEADER_SIZE))
+ {
+ return NULL; //To prevent overflow in next line
+ }
+
+ size += HEADER_SIZE; //We need a memory for header too
+ current_header = &_sdcc_heap_start;
+
+ while (1)
+ {
+ // current
+ // | len next
+ // v v v
+ //....*****.........******....
+ // ^^^^^^^^^
+ // spare
+
+ if ((((unsigned int)current_header->next) -
+ ((unsigned int)current_header) -
+ current_header->len) >= size)
+ {
+ break; //if spare is more than need
+ }
+ current_header = current_header->next; //else try next
+ if (!current_header->next)
+ {
+ return NULL; //if end_of_list reached
+ }
+ }
+
+ if (!current_header->len)
+ { //This code works only for first_header in the list and only
+ current_header->len = size; //for first allocation
+ return ¤t_header->mem;
+ }
+ else
+ {
+ //else create new header at the begin of spare
+ new_header = (MEMHEADER * )((char *)current_header + current_header->len);
+ new_header->next = current_header->next; //and plug it into the chain
+ new_header->prev = current_header;
+ current_header->next = new_header;
+ if (new_header->next)
+ {
+ new_header->next->prev = new_header;
+ }
+ new_header->len = size; //mark as used
+ return &new_header->mem;
+ }
+}
+
+#else
//--------------------------------------------------------------------
//Written by Dmitry S. Obukhov, 1997
// xdata - variable in external memory (just RAM)
//--------------------------------------------------------------------
- #define MEMHEADER struct MAH// Memory Allocation Header
-
- MEMHEADER
- {
- MEMHEADER xdata * next;
- MEMHEADER xdata * prev;
- unsigned int len;
- unsigned char mem;
- };
-
- #define HEADER_SIZE (sizeof(MEMHEADER)-1)
- #define NULL (void xdata * ) 0
+ #define HEADER_SIZE sizeof(MEMHEADER)
+ MEMHEADER xdata * _sdcc_first_memheader;
- //Static here means: can be accessed from this module only
- static MEMHEADER xdata * FIRST_MEMORY_HEADER_PTR;
- void init_dynamic_memory(MEMHEADER xdata * array, unsigned int size)
+ void init_dynamic_memory(void xdata * heap, unsigned int size)
{
//This function MUST be called after the RESET.
- //Parameters: array - pointer to memory allocated by the linker
- // size - size of this memory pool
+ //Parameters: heap - pointer to memory allocated by the linker
+ // size - size of this memory pool
//Example:
// #define DYNAMIC_MEMORY_SIZE 0x2000
// .....
// current_buffer = malloc(0x100);
//
//
+ MEMHEADER xdata * array = (MEMHEADER xdata *)heap;
- if ( !array ) /*Reserved memory starts on 0x0000 but it's NULL...*/
+ if ( !array ) //Reserved memory starts at 0x0000 but that's NULL...
{ //So, we lost one byte!
array = (MEMHEADER xdata * )((char xdata * ) array + 1) ;
- size --;
+ size--;
}
- FIRST_MEMORY_HEADER_PTR = array;
+ _sdcc_first_memheader = array;
//Reserve a mem for last header
- array->next = (MEMHEADER xdata * )(((char xdata * ) array) + size - HEADER_SIZE);
- array->next->next = NULL; //And mark it as last
- array->prev = NULL; //and mark first as first
+ array->next = (MEMHEADER xdata * )(((char xdata * ) array) + size - sizeof(MEMHEADER xdata *));
+ array->next->next = (MEMHEADER xdata * ) NULL; //And mark it as last
array->len = 0; //Empty and ready.
}
- void xdata * malloc (unsigned int size)
+ void xdata * malloc (unsigned int size)
{
register MEMHEADER xdata * current_header;
register MEMHEADER xdata * new_header;
- if (size>(0xFFFF-HEADER_SIZE)) return NULL; //To prevent overflow in next line
+ if (size>(0xFFFF-HEADER_SIZE)) return (void xdata *) NULL; //To prevent overflow in next line
size += HEADER_SIZE; //We need a memory for header too
- current_header = FIRST_MEMORY_HEADER_PTR;
+ current_header = _sdcc_first_memheader;
while (1)
{
if ((((unsigned int)current_header->next) -
((unsigned int)current_header) -
current_header->len) >= size) break; //if spare is more than need
- current_header = current_header->next; //else try next
- if (!current_header->next) return NULL; //if end_of_list reached
+ current_header = current_header->next; //else try next
+ if (!current_header->next) return (void xdata *) NULL; //if end_of_list reached
}
if (!current_header->len)
{ //This code works only for first_header in the list and only
current_header->len = size; //for first allocation
- return ((xdata *)&(current_header->mem));
+ return current_header->mem;
} //else create new header at the begin of spare
new_header = (MEMHEADER xdata * )((char xdata *)current_header + current_header->len);
new_header->next = current_header->next; //and plug it into the chain
- new_header->prev = current_header;
current_header->next = new_header;
- if (new_header->next) new_header->next->prev = new_header;
new_header->len = size; //mark as used
- return ((xdata *)&(new_header->mem));
+ return new_header->mem;
}
- void free (MEMHEADER xdata * p)
- {
- register MEMHEADER xdata * prev_header;
- if ( p ) //For allocated pointers only!
- {
- p = (MEMHEADER xdata * )((char xdata *) p - HEADER_SIZE); //to start of header
- if ( p->prev ) // For the regular header
- {
- prev_header = p->prev;
- prev_header->next = p->next;
- if (p->next) p->next->prev = prev_header;
- }
- else p->len = 0; //For the first header
- }
- }
//END OF MODULE
-
+#endif
projects / fw / sdcc / blobdiff