Implemented the basis for syscalls

A software interrupt with vector 0x50 will cause a syscall to start executing.
The EAX register will hold the syscall_num.
Other registers and the stack can be used to hold further arguments.

kernel/syscalls.h

@@ -0,0 +1,52 @@
+//
+// Created by nigel on 26/02/23.
+//
+#pragma once
+
+
+#include "terminal/kterm.h"
+#include "storage/vfs/vfs_types.h"
+
+
+void sys_version (){
+    printf("KERNEL VERSION v0.4\n");
+}
+
+void sys_open(){
+
+}
+
+void sys_read(FILE* file, char* data){
+    file->read(file, data, 512);
+}
+
+void sys_write(FILE* path, const char* data, size_t size){
+
+}
+
+// NOTE: this should become our standard!
+void syscall_handler(int syscall_no ,  uint32_t* args... ){
+    switch(syscall_no){
+        case 0x0:
+            printf("test!\n");
+            break;
+        case 0x5:
+            // SYS_OPEN
+            // sys_open();
+            break;
+        case 0x10:
+            // SYS_READ
+            // sys_read((FILE*)args[1], (char*) args[2] );
+            break;
+        case 0x20:
+            // SYS_WRITE
+            //sys_write((FILE*)args[1], (const char*) args[2], (size_t)args[3]);
+            break;
+        case 0x666:
+            // SYS_VERSION
+            sys_version();
+            break;
+    }
+}
+
+