addind more important kernel files and also fixing bugs

kernel/cpu.c

@@ -0,0 +1,35 @@
+#include "cpu.h"
+#include "serial.h"
+#include "terminal.h"
+
+void cpuid(uint32_t function, uint32_t *eax, uint32_t *ebx, uint32_t *ecx, uint32_t *edx) {
+    asm volatile (
+        "cpuid"
+        : "=a"(*eax), "=b"(*ebx), "=c"(*ecx), "=d"(*edx)
+        : "a"(function)
+    );
+}
+
+void identify_cpu() {
+    uint32_t eax, ebx, ecx, edx;
+    char vendor[13];
+
+    cpuid(0, &eax, &ebx, &ecx, &edx);
+
+    *(uint32_t *)&vendor[0] = ebx;
+    *(uint32_t *)&vendor[4] = edx;
+    *(uint32_t *)&vendor[8] = ecx;
+    vendor[12] = '\0';
+
+    terminal_write("CPU Vendor: ");
+    terminal_write(vendor);
+    terminal_write("\n");
+
+    serial_write("CPU Vendor: ");
+    serial_write(vendor);
+    serial_write("\n");
+
+    terminal_write("CPUID max leaf: ");
+    print_hex(eax);  // You must implement this (see below)
+    terminal_write("\n");
+}