Added submodule filesHEADmaster

1 files changed, 114 insertions, 0 deletions

diff --git a/gbdk/gbdk-lib/libc/malloc.c b/gbdk/gbdk-lib/libc/malloc.c
new file mode 100644
index 00000000..965e47dd
--- /dev/null
+++ b/gbdk/gbdk-lib/libc/malloc.c
@@ -0,0 +1,114 @@
+/*-------------------------------------------------------------------------
+   malloc.c - allocate memory.
+
+   Copyright (C) 2015, Philipp Klaus Krause, pkk@spth.de
+
+   This library is free software; you can redistribute it and/or modify it
+   under the terms of the GNU General Public License as published by the
+   Free Software Foundation; either version 2, or (at your option) any
+   later version.
+
+   This library 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 General Public License for more details.
+
+   You should have received a copy of the GNU General Public License 
+   along with this library; see the file COPYING. If not, write to the
+   Free Software Foundation, 51 Franklin Street, Fifth Floor, Boston,
+   MA 02110-1301, USA.
+
+   As a special exception, if you link this library with other files,
+   some of which are compiled with SDCC, to produce an executable,
+   this library does not by itself cause the resulting executable to
+   be covered by the GNU General Public License. This exception does
+   not however invalidate any other reasons why the executable file
+   might be covered by the GNU General Public License.
+-------------------------------------------------------------------------*/
+
+#include <stdlib.h>
+#include <stddef.h>
+
+#if defined(__SDCC_mcs51) || defined(__SDCC_ds390) || defined(__SDCC_ds400)
+#define HEAPSPACE __xdata
+#elif defined(__SDCC_pdk13) || defined(__SDCC_pdk14) || defined(__SDCC_pdk15)
+#define HEAPSPACE __near
+#else
+#define HEAPSPACE
+#endif
+
+typedef struct header HEAPSPACE header_t;
+
+struct header
+{
+	header_t *next; // Next block. Linked list of all blocks, terminated by pointer to end of heap (or to the byte beyond the end of the heap).
+	header_t *next_free; // Next free block. Used in free blocks only. Overlaps with user data in non-free blocks. Linked list of free blocks, 0-terminated.
+};
+
+header_t *HEAPSPACE __sdcc_heap_free; // First free block, 0 if no free blocks.
+
+extern header_t __sdcc_heap;
+#define HEAP_START &__sdcc_heap
+
+#if defined(__SDCC_mcs51) || defined(__SDCC_ds390) || defined(__SDCC_ds400) || defined(__SDCC_hc08) || defined(__SDCC_s08)
+
+extern const unsigned int __sdcc_heap_size;
+#define HEAP_END (struct header HEAPSPACE *)((char HEAPSPACE *)&__sdcc_heap + (__sdcc_heap_size - 1)) // -1 To be sure that HEAP_END is bigger than HEAP_START.
+
+#else
+
+extern header_t __sdcc_heap_end; // Just beyond the end of the heap. Must be higher in memory than _sdcc_heap_start.
+#define HEAP_END &__sdcc_heap_end
+
+#endif
+
+void __sdcc_heap_init(void)
+{
+	__sdcc_heap_free = HEAP_START;
+	__sdcc_heap_free->next = HEAP_END;
+	__sdcc_heap_free->next_free = 0;
+}
+
+#if defined(__SDCC_mcs51) || defined(__SDCC_ds390) || defined(__SDCC_ds400)
+void HEAPSPACE *malloc(size_t size)
+#else
+void *malloc(size_t size)
+#endif
+{
+	header_t *h;
+	header_t *HEAPSPACE *f;
+
+#if defined(__SDCC_mcs51) || defined(__SDCC_ds390) || defined(__SDCC_ds400) || defined(__SDCC_hc08) || defined(__SDCC_s08)
+	if(!__sdcc_heap_free)
+		__sdcc_heap_init();
+#endif
+
+	if(!size || size + offsetof(struct header, next_free) < size)
+		return(0);
+	size += offsetof(struct header, next_free);
+	if(size < sizeof(struct header)) // Requiring a minimum size makes it easier to implement free(), and avoid memory leaks.
+		size = sizeof(struct header);
+
+	for(h = __sdcc_heap_free, f = &__sdcc_heap_free; h; f = &(h->next_free), h = h->next_free)
+	{
+		size_t blocksize = (char HEAPSPACE *)(h->next) - (char HEAPSPACE *)h;
+		if(blocksize >= size) // Found free block of sufficient size.
+		{
+			if(blocksize >= size + sizeof(struct header)) // It is worth creating a new free block
+			{
+				header_t *const newheader = (header_t *const)((char HEAPSPACE *)h + size);
+				newheader->next = h->next;
+				newheader->next_free = h->next_free;
+				*f = newheader;
+				h->next = newheader;
+			}
+			else
+				*f = h->next_free;
+
+			return(&(h->next_free));
+		}
+	}
+
+	return(0);
+}
+