diff --git a/runtime/runtime.c b/runtime/runtime.c
index 0cb2b90be..af1da54c8 100644
--- a/runtime/runtime.c
+++ b/runtime/runtime.c
@@ -618,7 +618,7 @@ aint inner_hash (aint depth, auint acc, void *p) {
 
 extern void *LstringInt (char *b) {
   aint n;
-  sscanf(b, "%lld", &n);
+  sscanf(b, "%" SCNdAI, &n);
   return (void *)BOX(n);
 }
 
@@ -1274,7 +1274,7 @@ extern aint Lread () {
 
   printf("> ");
   fflush(stdout);
-  scanf("%lli", &result);
+  scanf("%" SCNdAI, &result);
 
   return BOX(result);
 }
@@ -1291,7 +1291,7 @@ extern int Lbinoperror2 (void) {
 
 /* Lwrite is an implementation of the "write" construct */
 extern aint Lwrite (aint n) {
-  printf("%lld\n", UNBOX(n));
+  printf("%" PRIdAI "\n", UNBOX(n));
   fflush(stdout);
 
   return 0;
diff --git a/runtime/runtime_common.h b/runtime/runtime_common.h
index e69b132f3..e1dadbcd1 100644
--- a/runtime/runtime_common.h
+++ b/runtime/runtime_common.h
@@ -10,27 +10,21 @@
 
 #if defined(__x86_64__) || defined(__ppc64__)
 #define X86_64
-#else
 #endif
 
 typedef size_t ptrt;  // pointer type, because can hold a pointer on a corresponding platform
 
-typedef
 #ifdef X86_64
-int64_t
+typedef int64_t aint;  // adaptive int
+typedef uint64_t auint;  // adaptive unsigned int
+#define PRIdAI PRId64
+#define SCNdAI SCNd64
 #else
-int32_t
+typedef int32_t aint;  // adaptive int
+typedef uint32_t auint;  // adaptive unsigned int
+#define PRIdAI PRId32
+#define SCNdAI SCNd32
 #endif
-aint;  // adaptive int
-
-typedef
-#ifdef X86_64
-uint64_t
-#else
-uint32_t
-#endif
-auint;  // adaptive unsigned int
-
 
 #define STRING_TAG 0x00000001
 #define ARRAY_TAG 0x00000003