First commit

.gitignore

@@ -0,0 +1 @@
+*.exe

Makefile

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+CC = clang
+CFLAGS = -Wall -Wextra -Werror -pedantic -std=c11 -nostdlib -static -Oz -ffreestanding
+LDFLAGS = -Wl,/SUBSYSTEM:CONSOLE,/ENTRY:_start -fuse-ld=lld
+LIBS = -lkernel32 -luser32
+SOURCES = main.c axl.c
+TARGET = prog.exe
+
+all: $(TARGET)
+
+$(TARGET): $(SOURCES)
+	$(CC) $(CFLAGS) $(SOURCES) -o $(TARGET) $(LDFLAGS) $(LIBS)
+clean:
+	rm -f $(TARGET)
+
+.PHONY: all clean
+

axl.c

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+#include "axl.h"
+
+static uint8_t memory[AXL_HEAP_SIZE];
+
+struct mb_header
+{
+    uint32_t size;
+    bool is_free;
+    struct mb_header* next;
+};
+
+typedef struct mb_header mb_header;
+
+#define MB_HEADER_SIZE sizeof(mb_header)
+
+static mb_header* root = 0; 
+
+void* axl_memset(void* ptr, int8_t c, int32_t n)
+{
+    if(ptr)
+    {
+        for(int32_t i = 0; i < n; i++)
+        {
+            ((int8_t*)ptr)[i] = c; 
+        }
+    }
+
+    return ptr;
+}
+
+void axl_init(void)
+{
+    static bool axl_initialized = false;
+
+    if(!axl_initialized)
+    {
+        axl_memset(memory, 0, AXL_HEAP_SIZE);
+        root = (mb_header*)memory;
+        root->is_free = true;
+        root->next = NULL;
+        root->size = AXL_HEAP_SIZE - MB_HEADER_SIZE; 
+        axl_initialized = true;
+    }
+}
+
+mb_header* axl_find_mb(uint32_t req_size)
+{
+    mb_header* block = root; 
+
+    while(block != NULL)
+    {
+        if(block->is_free && block->size >= req_size)
+        {
+            return block;
+        }
+        block = block->next;
+    }
+
+    return NULL;
+}
+
+void axl_split_mb(mb_header* block, uint32_t size)
+{
+    if(block->size > size + MB_HEADER_SIZE)
+    {
+        mb_header* new_block = (mb_header*)((uint8_t*)block + MB_HEADER_SIZE + size);
+        new_block->size = block->size - size - MB_HEADER_SIZE;
+        new_block->is_free = true; 
+        new_block->next = block->next;
+
+        block->size = size; 
+        block->next = new_block;
+    }
+}
+
+void* axl_malloc(uint32_t size)
+{
+    if(size > AXL_HEAP_SIZE - MB_HEADER_SIZE)
+    {
+        return NULL;
+    }
+
+    mb_header* free_block = axl_find_mb(size);
+
+    if(!free_block)
+    {
+        return NULL;
+    }
+
+    axl_split_mb(free_block, size);
+    free_block->is_free = false;
+
+    return (void*)((uint8_t*)free_block + MB_HEADER_SIZE);
+}
+
+void axl_free(void* ptr)
+{
+    if(!ptr)
+    {
+        return;
+    }
+
+    mb_header* block = (mb_header*)((uint8_t*)ptr - MB_HEADER_SIZE);
+    mb_header* next_block = block->next;
+    block->is_free = true; 
+
+    if(next_block != NULL && next_block->is_free)
+    {
+        block->size += next_block->size + MB_HEADER_SIZE;
+        block->next = next_block->next;
+    }
+}

axl.h

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+#ifndef AXL_H
+#define AXL_H
+
+#ifndef AXL_HEAP_SIZE
+#define AXL_HEAP_SIZE 1024 * 1024 * 16 
+#endif
+
+#include <stdbool.h>
+#include <stdint.h>
+#include <stddef.h>
+
+void axl_init(void);
+void* axl_malloc(uint32_t size);
+void* axl_memset(void* ptr, int8_t c, int32_t n);
+void axl_free(void* ptr);
+
+#endif

main.c

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+#include "axl.h"
+#include <windows.h>
+
+int _start(void)  // Entry point on Linux
+{
+    MessageBoxA(NULL, "wawa", "fffff", MB_OK | MB_ICONINFORMATION);
+    axl_init();
+
+    int* f = axl_malloc(sizeof(int));
+    *f = 4;
+    axl_free(f);
+   
+    (void)f;
+
+    Sleep(2);
+
+    while(true){}
+
+    return 0;
+}