5 files changed, 13 insertions, 5 deletions
diff --git a/mdk-stage1/dietlibc/liblatin1/latin1-iscntrl.c b/mdk-stage1/dietlibc/liblatin1/latin1-iscntrl.c
index b0c3605b0..5a6361442 100644
--- a/mdk-stage1/dietlibc/liblatin1/latin1-iscntrl.c
+++ b/mdk-stage1/dietlibc/liblatin1/latin1-iscntrl.c
@@ -1,5 +1,6 @@
 #include <ctype.h>
 
-int iscntrl(int c) {
+int iscntrl(int x) {
+  unsigned char c=x&0xff;
   return (c<32) || (c>=127 && c<=160);
 }
diff --git a/mdk-stage1/dietlibc/liblatin1/latin1-isgraph.c b/mdk-stage1/dietlibc/liblatin1/latin1-isgraph.c
index c8d4a5df0..e79a19e52 100644
--- a/mdk-stage1/dietlibc/liblatin1/latin1-isgraph.c
+++ b/mdk-stage1/dietlibc/liblatin1/latin1-isgraph.c
@@ -1,4 +1,7 @@
-int isgraph(int c) {
+#include <ctype.h>
+
+int isgraph(int x) {
+  unsigned char c=x&0xff;
   return (c>=33 && c<=126) || (c>=161 && c<=255);
 }
 
diff --git a/mdk-stage1/dietlibc/liblatin1/latin1-islower.c b/mdk-stage1/dietlibc/liblatin1/latin1-islower.c
index cab1a5171..c5ad18d1e 100644
--- a/mdk-stage1/dietlibc/liblatin1/latin1-islower.c
+++ b/mdk-stage1/dietlibc/liblatin1/latin1-islower.c
@@ -1,5 +1,6 @@
 #include <ctype.h>
 
 int islower(int c) {
-  return (c>='a' && c<='z') || (c>=223 && c<=255 && c!=247);
+  unsigned char x=c&0xff;
+  return (x>='a' && x<='z') || (x>=223 && x<=255 && x!=247);
 }
diff --git a/mdk-stage1/dietlibc/liblatin1/latin1-isprint.c b/mdk-stage1/dietlibc/liblatin1/latin1-isprint.c
index f632483a0..9493892b1 100644
--- a/mdk-stage1/dietlibc/liblatin1/latin1-isprint.c
+++ b/mdk-stage1/dietlibc/liblatin1/latin1-isprint.c
@@ -1,4 +1,6 @@
+#include <ctype.h>
 
-int isprint(int c) {
+int isprint(int x) {
+  unsigned char c=x&0xff;
   return (c>=32 && c<=126) || (c>=160 && c<=255);
 }
diff --git a/mdk-stage1/dietlibc/liblatin1/latin1-isupper.c b/mdk-stage1/dietlibc/liblatin1/latin1-isupper.c
index 1c1d59db8..a024548fd 100644
--- a/mdk-stage1/dietlibc/liblatin1/latin1-isupper.c
+++ b/mdk-stage1/dietlibc/liblatin1/latin1-isupper.c
@@ -1,5 +1,6 @@
 #include <ctype.h>
 
 int isupper(int c) {
-  return (c>='A' && c<='Z') || (c>=192 && c<=222 && c!=215);
+  unsigned char x=c&0xff;
+  return (x>='A' && x<='Z') || (x>=192 && x<=222 && x!=215);
 }