diff --git a/cpu/6502/6502-conf.h b/cpu/6502/6502-conf.h
index c469803f9..f6489364a 100644
--- a/cpu/6502/6502-conf.h
+++ b/cpu/6502/6502-conf.h
@@ -1,9 +1,10 @@
 #ifndef __6502_CONF_H__
 #define __6502_CONF_H__
 
-typedef unsigned char  u8_t;
+typedef unsigned char   u8_t;
 typedef unsigned short u16_t;
 typedef unsigned long  u32_t;
+typedef          long  s32_t;
 typedef unsigned short uip_stats_t;
 
 #define CC_CONF_REGISTER_ARGS 1
diff --git a/platform/cooja/contiki-conf.h b/platform/cooja/contiki-conf.h
index 74b932998..af5c9f9a6 100644
--- a/platform/cooja/contiki-conf.h
+++ b/platform/cooja/contiki-conf.h
@@ -32,7 +32,7 @@
  *
  * This file is part of the Contiki desktop OS
  *
- * $Id: contiki-conf.h,v 1.4 2007/04/11 00:26:27 oliverschmidt Exp $
+ * $Id: contiki-conf.h,v 1.5 2007/05/12 20:58:54 oliverschmidt Exp $
  *
  */
 
@@ -79,6 +79,14 @@ typedef uint16_t u16_t;
  */
 typedef uint32_t u32_t;
 
+/**
+ * The 32-bit signed data type.
+ *
+ * This may have to be tweaked for your particular compiler. "signed
+ * short" works for most compilers.
+ */
+typedef int32_t s32_t;
+
 /**
  * The statistics data type.
  *
diff --git a/platform/esb/contiki-conf.h b/platform/esb/contiki-conf.h
index 01b9a98ca..162ccb606 100644
--- a/platform/esb/contiki-conf.h
+++ b/platform/esb/contiki-conf.h
@@ -58,6 +58,14 @@ typedef unsigned short u16_t;
  */
 typedef unsigned long u32_t;
 
+/**
+ * The 32-bit signed data type.
+ *
+ * This may have to be tweaked for your particular compiler. "signed
+ * long" works for most compilers.
+ */
+typedef long s32_t;
+
 /**
  * The statistics data type.
  *
diff --git a/platform/gtk/contiki-conf.h b/platform/gtk/contiki-conf.h
index 261f8097d..1cee8e733 100644
--- a/platform/gtk/contiki-conf.h
+++ b/platform/gtk/contiki-conf.h
@@ -130,6 +130,7 @@ typedef unsigned char u8_t;
 typedef unsigned short u16_t;
 
 typedef unsigned long u32_t;
+typedef          long s32_t;
 
 /**
  * The statistics data type.
diff --git a/platform/minimal-net/contiki-conf.h b/platform/minimal-net/contiki-conf.h
index d5a6a7edf..99573c906 100644
--- a/platform/minimal-net/contiki-conf.h
+++ b/platform/minimal-net/contiki-conf.h
@@ -28,7 +28,7 @@
  *
  * This file is part of the Contiki operating system.
  *
- * @(#)$Id: contiki-conf.h,v 1.4 2007/04/11 00:27:17 oliverschmidt Exp $
+ * @(#)$Id: contiki-conf.h,v 1.5 2007/05/12 21:00:56 oliverschmidt Exp $
  */
 
 #ifndef __CONTIKI_CONF_H__
@@ -44,9 +44,10 @@
 #define CCIF
 #define CLIF
 
-typedef uint8_t u8_t;
+typedef uint8_t   u8_t;
 typedef uint16_t u16_t;
 typedef uint32_t u32_t;
+typedef  int32_t s32_t;
 typedef unsigned short uip_stats_t;
 
 #define UIP_CONF_MAX_CONNECTIONS 40
diff --git a/platform/native/contiki-conf.h b/platform/native/contiki-conf.h
index 2151f9829..e07e7272d 100644
--- a/platform/native/contiki-conf.h
+++ b/platform/native/contiki-conf.h
@@ -28,7 +28,7 @@
  *
  * This file is part of the Contiki operating system.
  *
- * @(#)$Id: contiki-conf.h,v 1.4 2007/04/11 00:27:56 oliverschmidt Exp $
+ * @(#)$Id: contiki-conf.h,v 1.5 2007/05/12 21:01:20 oliverschmidt Exp $
  */
 
 #ifndef __CONTIKI_CONF_H__
@@ -45,9 +45,10 @@
 #define CCIF
 #define CLIF
 
-typedef uint8_t u8_t;
+typedef uint8_t   u8_t;
 typedef uint16_t u16_t;
 typedef uint32_t u32_t;
+typedef  int32_t s32_t;
 typedef unsigned short uip_stats_t;
 
 #define UIP_CONF_MAX_CONNECTIONS 40
diff --git a/platform/netsim/contiki-conf.h b/platform/netsim/contiki-conf.h
index e0e9f0f38..f52c0b27a 100644
--- a/platform/netsim/contiki-conf.h
+++ b/platform/netsim/contiki-conf.h
@@ -32,7 +32,7 @@
  *
  * This file is part of the Contiki desktop OS
  *
- * $Id: contiki-conf.h,v 1.6 2007/04/11 00:28:26 oliverschmidt Exp $
+ * $Id: contiki-conf.h,v 1.7 2007/05/12 21:01:54 oliverschmidt Exp $
  *
  */
 
@@ -77,6 +77,14 @@ typedef uint16_t u16_t;
  */
 typedef uint32_t u32_t;
 
+/**
+ * The 32-bit signed data type.
+ *
+ * This may have to be tweaked for your particular compiler. "signed
+ * short" works for most compilers.
+ */
+typedef int32_t s32_t;
+
 /**
  * The statistics data type.
  *
diff --git a/platform/sky/contiki-conf.h b/platform/sky/contiki-conf.h
index 559298595..d33a16af0 100644
--- a/platform/sky/contiki-conf.h
+++ b/platform/sky/contiki-conf.h
@@ -1,5 +1,5 @@
 /* -*- C -*- */
-/* @(#)$Id: contiki-conf.h,v 1.14 2007/04/11 15:22:05 bg- Exp $ */
+/* @(#)$Id: contiki-conf.h,v 1.15 2007/05/12 21:02:23 oliverschmidt Exp $ */
 
 #ifndef CONTIKI_CONF_H
 #define CONTIKI_CONF_H
@@ -71,9 +71,10 @@ void msp430_cpu_init(void);	/* Rename to cpu_init() later! */
 /* Button sensors. */
 #define IRQ_PORT2 0x02
 
-typedef unsigned char u8_t;
+typedef unsigned char   u8_t;
 typedef unsigned short u16_t;
-typedef unsigned long u32_t;
+typedef unsigned long  u32_t;
+typedef          long  s32_t;
 typedef unsigned short uip_stats_t;
 typedef unsigned short clock_time_t;
 
diff --git a/platform/win32/contiki-conf.h b/platform/win32/contiki-conf.h
index e85605757..a82a902c3 100644
--- a/platform/win32/contiki-conf.h
+++ b/platform/win32/contiki-conf.h
@@ -116,9 +116,10 @@ typedef unsigned long clock_time_t;
 
 
 
-typedef unsigned char u8_t;
+typedef unsigned char   u8_t;
 typedef unsigned short u16_t;
-typedef unsigned long u32_t;
+typedef unsigned long  u32_t;
+typedef          long  s32_t;
 typedef unsigned short uip_stats_t;
 
 #define UIP_CONF_MAX_CONNECTIONS 40