diff --git a/mach/6500/as/mach1.c b/mach/6500/as/mach1.c
index 2243d1f8e..cef0ab8d2 100644
--- a/mach/6500/as/mach1.c
+++ b/mach/6500/as/mach1.c
@@ -9,3 +9,6 @@
  */
 
 #define fits_zeropage(x)	(lowb(x) == (int)(x))
+
+void branch(register int opc, expr_t exp);
+void code(expr_t exp, register int opc1, register int opc2);
diff --git a/mach/6500/as/mach5.c b/mach/6500/as/mach5.c
index 2e073d709..53e121214 100644
--- a/mach/6500/as/mach5.c
+++ b/mach/6500/as/mach5.c
@@ -8,9 +8,7 @@
  * Mostek 6500 special routines.
  */
 
-branch(opc, exp)
-register int	opc;
-expr_t		exp;
+void branch(register int opc, expr_t exp)
 {
 	register int	dist;
 
@@ -29,9 +27,7 @@ expr_t		exp;
 	}
 }
 
-code(exp, opc1, opc2)
-expr_t		exp;
-register int	opc1, opc2;
+void code(expr_t exp, register int opc1, register int opc2)
 {
 	if (small((exp.typ & S_TYP) == S_ABS && fits_zeropage(exp.val), 1)) {
 		emit1(opc1); emit1(exp.val);