Update

kernel/kernel.c

@@ -11,10 +11,61 @@ static volatile struct limine_terminal_request terminal_request = {
     .revision = 0
 };
 
-static void done(void) {
+// GCC and Clang reserve the right to generate calls to the following
-    for (;;) {
+// 4 functions even if they are not directly called.
-        asm ("hlt");
+// Implement them as the C specification mandates.
+// DO NOT remove or rename these functions, or stuff will eventually break!
+// They CAN be moved to a different .c file.
+
+void *memcpy(void *dest, const void *src, size_t n) {
+    uint8_t *pdest = (uint8_t *)dest;
+    const uint8_t *psrc = (const uint8_t *)src;
+
+    for (size_t i = 0; i < n; i++) {
+        pdest[i] = psrc[i];
     }
+
+    return dest;
+}
+
+void *memset(void *s, int c, size_t n) {
+    uint8_t *p = (uint8_t *)s;
+
+    for (size_t i = 0; i < n; i++) {
+        p[i] = (uint8_t)c;
+    }
+
+    return s;
+}
+
+void *memmove(void *dest, const void *src, size_t n) {
+    uint8_t *pdest = (uint8_t *)dest;
+    const uint8_t *psrc = (const uint8_t *)src;
+
+    if (src > dest) {
+        for (size_t i = 0; i < n; i++) {
+            pdest[i] = psrc[i];
+        }
+    } else if (src < dest) {
+        for (size_t i = n; i > 0; i--) {
+            pdest[i-1] = psrc[i-1];
+        }
+    }
+
+    return dest;
+}
+
+int memcmp(const void *s1, const void *s2, size_t n) {
+    const uint8_t *p1 = (const uint8_t *)s1;
+    const uint8_t *p2 = (const uint8_t *)s2;
+
+    for (size_t i = 0; i < n; i++) {
+        if (p1[i] != p2[i]) {
+            return p1[i] < p2[i] ? -1 : 1;
+        }
+    }
+
+    return 0;
 }
 
 // Our quick and dirty strlen() implementation.
@@ -26,12 +77,22 @@ size_t strlen(const char *str) {
     return ret;
 }
 
+// Halt and catch fire function.
+static void hcf(void) {
+    asm ("cli");
+    for (;;) {
+        asm ("hlt");
+    }
+}
+
 // The following will be our kernel's entry point.
+// If renaming _start() to something else, make sure to change the
+// linker script accordingly.
 void _start(void) {
     // Ensure we got a terminal
     if (terminal_request.response == NULL
      || terminal_request.response->terminal_count < 1) {
-        done();
+        hcf();
     }
 
     // We should now be able to call the Limine terminal to print out
@@ -42,5 +103,5 @@ void _start(void) {
     terminal_request.response->write(terminal, hello_msg, strlen(hello_msg));
 
     // We're done, just hang...
-    done();
+    hcf();
 }