diff --git a/cpu/arm_common/arm_cpu.c b/cpu/arm_common/arm_cpu.c
index d7d7efbe93..9c71538845 100644
--- a/cpu/arm_common/arm_cpu.c
+++ b/cpu/arm_common/arm_cpu.c
@@ -38,7 +38,7 @@ char *thread_stack_init(thread_task_func_t task_func, void *arg, void *stack_sta
 {
     unsigned int *stk;
     int i;
-    stk = (unsigned int *)((unsigned int)stack_start + stack_size);
+    stk = (unsigned int *)((uintptr_t)stack_start + stack_size);
     stk--;
 
     *stk = STACK_MARKER;
diff --git a/cpu/atmega_common/thread_arch.c b/cpu/atmega_common/thread_arch.c
index cdd2829b23..e19dc5927c 100644
--- a/cpu/atmega_common/thread_arch.c
+++ b/cpu/atmega_common/thread_arch.c
@@ -74,7 +74,7 @@ char *thread_arch_stack_init(void *(*task_func)(void *), void *arg, void *stack_
     uint8_t *stk;
 
     /* AVR uses 16 Bit or two 8 Bit registers for storing  pointers*/
-    stk = (uint8_t *)((uint16_t)stack_start + stack_size);
+    stk = (uint8_t *)((uintptr_t)stack_start + stack_size);
 
     /* put marker on stack */
     stk--;
diff --git a/cpu/cortex-m0_common/thread_arch.c b/cpu/cortex-m0_common/thread_arch.c
index d5c7632d56..8508e376bd 100644
--- a/cpu/cortex-m0_common/thread_arch.c
+++ b/cpu/cortex-m0_common/thread_arch.c
@@ -66,7 +66,7 @@ char *thread_arch_stack_init(void *(*task_func)(void *),
                              int stack_size)
 {
     uint32_t *stk;
-    stk = (uint32_t *)((uint32_t)stack_start + stack_size);
+    stk = (uint32_t *)((uintptr_t)stack_start + stack_size);
 
     /* marker */
     stk--;
diff --git a/cpu/cortex-m3_common/thread_arch.c b/cpu/cortex-m3_common/thread_arch.c
index 3bc7f68b05..c1be4b82b7 100644
--- a/cpu/cortex-m3_common/thread_arch.c
+++ b/cpu/cortex-m3_common/thread_arch.c
@@ -57,7 +57,7 @@ static void context_restore(void) NORETURN;
 char *thread_arch_stack_init(void *(*task_func)(void *), void *arg, void *stack_start, int stack_size)
 {
     uint32_t *stk;
-    stk = (uint32_t *)((uint32_t)stack_start + stack_size);
+    stk = (uint32_t *)((uintptr_t)stack_start + stack_size);
 
     /* marker */
     stk--;
diff --git a/cpu/cortex-m4_common/thread_arch.c b/cpu/cortex-m4_common/thread_arch.c
index 7fa0bd4aa4..5ad517c0a5 100644
--- a/cpu/cortex-m4_common/thread_arch.c
+++ b/cpu/cortex-m4_common/thread_arch.c
@@ -63,7 +63,7 @@ char *thread_arch_stack_init(void *(*task_func)(void *),
                              int stack_size)
 {
     uint32_t *stk;
-    stk = (uint32_t *)((uint32_t)stack_start + stack_size);
+    stk = (uint32_t *)((uintptr_t)stack_start + stack_size);
 
     /* marker */
     stk--;
diff --git a/cpu/lpc1768/atom.c b/cpu/lpc1768/atom.c
index 3fedce6e13..cdd7d32142 100644
--- a/cpu/lpc1768/atom.c
+++ b/cpu/lpc1768/atom.c
@@ -114,7 +114,7 @@ NORETURN void sched_task_return(void)
 char * thread_stack_init(void *(*task_func)(void *), void *arg, void *stack_start, int stack_size)
 {
     unsigned int * stk;
-    stk = (unsigned int *) (stack_start + stack_size);
+    stk = (unsigned int *) ((uintptr_t) stack_start + stack_size);
 
     /* marker */
     stk--;
diff --git a/cpu/msp430-common/cpu.c b/cpu/msp430-common/cpu.c
index b332d2b46b..699a4da258 100644
--- a/cpu/msp430-common/cpu.c
+++ b/cpu/msp430-common/cpu.c
@@ -64,7 +64,7 @@ __attribute__((section (".fini9"))) void __main_epilogue(void) { __asm__("ret");
 //----------------------------------------------------------------------------
 char *thread_stack_init(thread_task_func_t task_func, void *arg, void *stack_start, int stack_size)
 {
-    unsigned short stk = (unsigned short)(stack_start + stack_size);
+    unsigned short stk = (unsigned short)((uintptr_t) stack_start + stack_size);
 
     /* ensure correct stack alignment (on 16-bit boundary) */
     stk &= 0xfffe;