diff --git a/litex/soc/software/include/base/stddef.h b/litex/soc/software/include/base/stddef.h
index 4f9a211f7..858d70b3e 100644
--- a/litex/soc/software/include/base/stddef.h
+++ b/litex/soc/software/include/base/stddef.h
@@ -11,8 +11,13 @@ extern "C" {
 #define NULL ((void *)0)
 #endif
 
+#ifdef __LP64__
 typedef unsigned long size_t;
 typedef long ptrdiff_t;
+#else
+typedef unsigned int size_t;
+typedef int ptrdiff_t;
+#endif
 
 #define offsetof(type, member) __builtin_offsetof(type, member)
 
diff --git a/litex/soc/software/include/base/stdint.h b/litex/soc/software/include/base/stdint.h
index bff5d0983..a17e1739a 100644
--- a/litex/soc/software/include/base/stdint.h
+++ b/litex/soc/software/include/base/stdint.h
@@ -5,8 +5,13 @@
 extern "C" {
 #endif
 
+#ifdef __LP64__
+typedef long intptr_t;
+typedef unsigned long uintptr_t;
+#else
 typedef int intptr_t;
 typedef unsigned int uintptr_t;
+#endif
 
 typedef unsigned long long uint64_t;
 typedef unsigned int uint32_t;