feat: added UART support with a basic kprint in kernel

wip: DTB

Kernel/Source/Support/BridgingHeader.h

@@ -0,0 +1,10 @@
+#include "bootinfo.h"
+#include <stdint.h>
+
+static inline void mmio_write32(uintptr_t addr, uint32_t val) {
+    *(volatile uint32_t *)addr = val;
+}
+
+static inline uint32_t mmio_read32(uintptr_t addr) {
+    return *(volatile uint32_t *)addr;
+}

Kernel/Source/Support/stubs.c

@@ -0,0 +1,36 @@
+#include <stddef.h>
+#include <stdint.h>
+
+void* memmove(void* dest, const void* src, unsigned long n) {
+    unsigned char* d = (unsigned char*)dest;
+    const unsigned char* s = (const unsigned char*)src;
+    if (d < s) {
+        while (n--) *d++ = *s++;
+    } else {
+        d += n; s += n;
+        while (n--) *--d = *--s;
+    }
+    return dest;
+}
+
+void* memcpy(void* dest, const void* src, unsigned long n) {
+    return memmove(dest, src, n);
+}
+
+void* memset(void* dest, int c, unsigned long n) {
+    unsigned char* d = (unsigned char*)dest;
+    while (n--) *d++ = (unsigned char)c;
+    return dest;
+}
+
+// Stack protection
+long __stack_chk_guard = (long)0xDEADBEEFCAFEBABEULL;
+void __stack_chk_fail(void) { while (1); }
+
+// Swift runtime allocator stubs — should never be called in embedded mode
+int posix_memalign(void** ptr, unsigned long align, unsigned long size) {
+    (void)ptr; (void)align; (void)size;
+    while (1);
+}
+
+void free(void* ptr) { (void)ptr; }