--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/syscall.c	Tue Dec 19 09:56:09 2006 +0000
@@ -0,0 +1,68 @@
+/**
+ * $Id: syscall.c,v 1.1 2006-03-13 12:38:34 nkeynes Exp $
+ * 
+ * Routines to add hook functions that are callable from the SH4
+ *
+ * Copyright (c) 2005 Nathan Keynes.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include "dream.h"
+#include "mem.h"
+#include "syscall.h"
+#include "sh4/sh4core.h"
+
+
+struct syscall_hook {
+    syscall_hook_func_t hook;
+    sh4addr_t vector;
+} syscall_hooks[256];
+
+void syscall_add_hook( uint32_t hook_id, syscall_hook_func_t hook ) 
+{
+    hook_id &= 0xFF;
+    if( syscall_hooks[hook_id].hook != NULL )
+	WARN( "Overwriting existing hook %02X", hook_id );
+    syscall_hooks[hook_id].hook = hook;
+    syscall_hooks[hook_id].vector = 0;
+}
+
+void syscall_add_hook_vector( uint32_t hook_id, uint32_t vector_addr,
+			      syscall_hook_func_t hook )
+{
+    hook_id &= 0xFF;
+    syscall_add_hook( hook_id, hook );
+    syscall_hooks[hook_id].vector = vector_addr;
+    sh4_write_long( vector_addr, 0xFFFFFF00 + hook_id );
+}
+
+void syscall_invoke( uint32_t hook_id )
+{
+    hook_id &= 0xFF;
+    syscall_hook_func_t hook = syscall_hooks[hook_id].hook;
+    if( hook == NULL ) {
+	WARN( "Invoked non-existent hook %02X", hook_id );
+    } else {
+	hook(hook_id);
+    }
+}
+
+void syscall_repatch_vectors( )
+{
+    int i;
+    for( i=0; i<256; i++ ) {
+	if( syscall_hooks[i].hook != NULL &&
+	    syscall_hooks[i].vector != 0 ) {
+	    sh4_write_long( syscall_hooks[i].vector, 0xFFFFFF00 + i );
+	}
+    }
+}