--- hatari/src/falcon/dsp.c	2019/04/09 08:53:22	1.1.1.9
+++ hatari/src/falcon/dsp.c	2019/04/09 08:54:35	1.1.1.10
@@ -20,6 +20,8 @@
 	Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
 
+#include <ctype.h>
+
 #include "main.h"
 #include "sysdeps.h"
 #include "newcpu.h"
@@ -563,7 +565,7 @@ int DSP_GetRegisterAddress(const char *r
 		{ "Y1",  &dsp_core.registers[DSP_REG_Y1],  32, BITMASK(24) }
 	};
 	/* left, right, middle, direction */
-        int l, r, m, dir = 0;
+	int l, r, m, dir = 0;
 	unsigned int i, len;
 	char reg[MAX_REGNAME_LEN];
 
@@ -572,7 +574,7 @@ int DSP_GetRegisterAddress(const char *r
 	}
 
 	for (i = 0; i < sizeof(reg) && regname[i]; i++) {
-		reg[i] = toupper(regname[i]);
+		reg[i] = toupper((unsigned char)regname[i]);
 	}
 	if (i < 2 || regname[i]) {
 		/* too short or longer than any of the names */