diff --git a/m68k_in.c b/m68k_in.c
index cf0eb18..e5811b3 100644
--- a/m68k_in.c
+++ b/m68k_in.c
@@ -283,7 +283,7 @@ M68KMAKE_OPCODE_HANDLER_HEADER
 #include "m68kcpu.h"
 extern void m68040_fpu_op0(void);
 extern void m68040_fpu_op1(void);
-extern void m68881_mmu_ops();
+extern void m68881_mmu_ops(void);
 
 /* ======================================================================== */
 /* ========================= INSTRUCTION HANDLERS ========================= */
diff --git a/m68kcpu.c b/m68kcpu.c
index 112a817..aa1a3fc 100644
--- a/m68kcpu.c
+++ b/m68kcpu.c
@@ -40,7 +40,7 @@
 
 extern void m68040_fpu_op0(void);
 extern void m68040_fpu_op1(void);
-extern void m68881_mmu_ops();
+extern void m68881_mmu_ops(void);
 extern unsigned char m68ki_cycles[][0x10000];
 extern void (*m68ki_instruction_jump_table[0x10000])(void); /* opcode handler jump table */
 extern void m68ki_build_opcode_table(void);
diff --git a/m68kmmu.h b/m68kmmu.h
index faba371..b6d9098 100644
--- a/m68kmmu.h
+++ b/m68kmmu.h
@@ -177,7 +177,7 @@ uint pmmu_translate_addr(uint addr_in)
 
 */
 
-void m68881_mmu_ops()
+void m68881_mmu_ops(void)
 {
 	uint16 modes;
 	uint32 ea = m68ki_cpu.ir & 0x3f;