Started stack allocator.

This will replace the current linear allocator so we can free and
realloc memory correctly. This is especially important for the window
resizing due to a fixed LFB size.

2 files changed, 59 insertions, 8 deletions

diff --git a/libc/inc/mem.h b/libc/inc/mem.h
index cb64ce8..9aeeee9 100644
--- a/libc/inc/mem.h
+++ b/libc/inc/mem.h
@@ -7,8 +7,13 @@
 
 // Huh
 #ifdef kernel
-#define malloc(n) (void *)((HEAP += n) - n) // TODO: Implement real/better malloc/free
-#define free(ptr)
+#define HEAP_SIZE 0x10000
+#define HEAP_MAGIC 0x42
+void heap_init(u32 start);
+void *malloc(u32 size);
+void free(void *ptr);
+/* #define malloc(n) (void *)((HEAP += n) - n) // TODO: Implement real/better malloc/free */
+/* #define free(ptr) */
 #elif defined(userspace)
 #include <sys.h>
 #define malloc(n) (void *)sys1(SYS_MALLOC, n)
@@ -17,11 +22,8 @@
 #error "No lib target specified. Please use -Dkernel or -Duserspace"
 #endif
 
-u32 HEAP;
-u32 HEAP_START;
-
 void *memcpy(void *dest, const void *src, u32 n);
-void *memset(void *dest, int c, u32 n);
+void *memset(void *dest, int val, u32 n);
 int memcmp(const void *s1, const void *s2, u32 n);
 
 #endif
diff --git a/libc/mem.c b/libc/mem.c
index 4b7981f..4744a8b 100644
--- a/libc/mem.c
+++ b/libc/mem.c
@@ -1,7 +1,7 @@
 // MIT License, Copyright (c) 2020 Marvin Borner
 
 #include <def.h>
-#include <print.h>
+#include <mem.h>
 #include <sys.h>
 
 // Taken from jgraef at osdev
@@ -24,7 +24,7 @@ void *memcpy(void *dest, const void *src, u32 n)
 	return dest;
 }
 
-void *memset(void *dest, char val, u32 n)
+void *memset(void *dest, int val, u32 n)
 {
 	u32 num_dwords = n / 4;
 	u32 num_bytes = n % 4;
@@ -55,3 +55,52 @@ int memcmp(const void *s1, const void *s2, u32 n)
 	}
 	return 0;
 }
+
+#ifdef kernel
+
+static u32 *heap;
+static u32 index;
+
+void heap_init(u32 start)
+{
+	heap = (u32 *)start;
+	for (int i = 0; i < HEAP_SIZE; i++)
+		heap[i] = 0;
+	heap[0] = HEAP_MAGIC;
+	index = 1;
+}
+
+int count()
+{
+	int i = 0;
+	u32 *iterator = heap + 1;
+	do {
+		iterator += iterator[0] + 1;
+		i++;
+	} while (iterator[0] != 0);
+	return i;
+}
+
+void *malloc(u32 size)
+{
+	if (size < 1)
+		return NULL;
+
+	heap[index] = size;
+	index += size + 1;
+	return (void *)(heap + index - size);
+}
+
+// TODO: Implement free, realloc and find_smallest_hole
+void free(void *ptr)
+{
+	(void)ptr;
+}
+
+void *realloc(void *ptr, u32 size)
+{
+	(void)size;
+	return ptr;
+}
+
+#endif