diff --git a/cpu/sa1100/cpu.c b/cpu/sa1100/cpu.c
index b613fe7..34adf91 100644
--- a/cpu/sa1100/cpu.c
+++ b/cpu/sa1100/cpu.c
@@ -41,7 +41,7 @@
 #ifdef CONFIG_USE_IRQ
 	DECLARE_GLOBAL_DATA_PTR;
 
-	IRQ_STACK_START = _armboot_start - CFG_MALLOC_LEN - CFG_GBL_DATA_LEN - 4;
+	IRQ_STACK_START = _armboot_start - CFG_MALLOC_LEN - CFG_GBL_DATA_SIZE - 4;
 	FIQ_STACK_START = IRQ_STACK_START - CONFIG_STACKSIZE_IRQ;
 #endif
 	return 0;