diff --git a/src/mame/drivers/crystal.c b/src/mame/drivers/crystal.c
index 5d510300572..5d9135b7fac 100644
--- a/src/mame/drivers/crystal.c
+++ b/src/mame/drivers/crystal.c
@@ -237,7 +237,7 @@ static WRITE32_HANDLER(Banksw_w)
 
 static TIMER_CALLBACK( Timercb )
 {
-	int which = (int)ptr;
+	int which = (int)(FPTR)ptr;
 	static const int num[] = { 0, 1, 9, 10 };
 
 	if(!(Timerctrl[which]&2))
@@ -501,7 +501,7 @@ static MACHINE_START(crystal)
 
 	cpunum_set_irq_callback(0,icallback);
 	for (i=0; i<4; i++)
-		Timer[i] = timer_alloc(Timercb, (void*)i);
+		Timer[i] = timer_alloc(Timercb, (void*)(FPTR)i);
 
 	PatchReset();
 }
diff --git a/src/mame/drivers/megadriv.c b/src/mame/drivers/megadriv.c
index 1475a319654..76f0206c010 100644
--- a/src/mame/drivers/megadriv.c
+++ b/src/mame/drivers/megadriv.c
@@ -1408,7 +1408,7 @@ static int io_stage[3];
 
 static TIMER_CALLBACK( io_timeout_timer_callback )
 {
-	io_stage[(int)ptr] = -1;
+	io_stage[(int)(FPTR)ptr] = -1;
 }
 
 static void init_megadri6_io(void)
@@ -1417,7 +1417,7 @@ static void init_megadri6_io(void)
 
 	for (i=0; i<3; i++)
 	{
-		io_timeout[i] = timer_alloc(io_timeout_timer_callback, (void*)i);
+		io_timeout[i] = timer_alloc(io_timeout_timer_callback, (void*)(FPTR)i);
 		io_stage[i] = -1;
 	}
 }
diff --git a/src/mame/drivers/model2.c b/src/mame/drivers/model2.c
index 7d6cf43c988..03980052e3b 100644
--- a/src/mame/drivers/model2.c
+++ b/src/mame/drivers/model2.c
@@ -312,7 +312,7 @@ static WRITE32_HANDLER( timers_w )
 
 static TIMER_CALLBACK( model2_timer_cb )
 {
-	int tnum = (int)ptr;
+	int tnum = (int)(FPTR)ptr;
 	int bit = tnum + 2;
 
 	timer_adjust_oneshot(model2_timers[tnum], attotime_never, 0);
@@ -349,7 +349,7 @@ static MACHINE_RESET(model2_common)
 
 	for (i=0; i<4; i++)
 	{
-		model2_timers[i] = timer_alloc(model2_timer_cb, (void*)i);
+		model2_timers[i] = timer_alloc(model2_timer_cb, (void*)(FPTR)i);
 		timer_adjust_oneshot(model2_timers[i], attotime_never, 0);
 	}
 }