Add syscall sources

src/utils/syscall.c

@@ -0,0 +1,20 @@
+#include "syscall.h"
+#include "gdt.h"
+#include "libc/stdio.h"
+
+void syscall(){
+    int call_number;
+    asm("movl %%eax, %0":"=m"(call_number));
+    int user_ds=gdt_user_ds_base();
+    if(call_number==1){
+        int msg_addr;
+        asm("movl %%ebx, %0":"=m"(msg_addr));
+        char *msg=(char*)user_ds+msg_addr;
+        print(msg);
+    }
+    else{
+        print("Syscall ");
+        printi(call_number);
+        print(" unknown");
+    }
+}

src/utils/syscall.h

@@ -0,0 +1,6 @@
+#ifndef SYSCALL_H
+#define SYSCALL_H
+
+void syscall();
+
+#endif