diff --git a/engine/client/cl_main.c b/engine/client/cl_main.c
index 8b190ca6..667d0b90 100644
--- a/engine/client/cl_main.c
+++ b/engine/client/cl_main.c
@@ -2939,7 +2939,8 @@ void CL_AdjustClock( void )
 
 	if( fabs( cl.timedelta ) >= 0.001f )
 	{
-		double	msec, adjust, sign;
+		double msec, adjust;
+		float sign;
 
 		msec = ( cl.timedelta * 1000.0f );
 		sign = ( msec < 0 ) ? 1.0f : -1.0f;
diff --git a/engine/client/in_touch.c b/engine/client/in_touch.c
index 104c468e..17afada9 100644
--- a/engine/client/in_touch.c
+++ b/engine/client/in_touch.c
@@ -876,18 +876,18 @@ void Touch_DeleteProfile_f( void )
 
 void Touch_InitEditor( void )
 {
-	float x = 0.1 * (SCR_H/SCR_W);
-	float y = 0.05;
+	float x = 0.1f * (SCR_H/SCR_W);
+	float y = 0.05f;
 
 	Touch_ClearList( &touch.list_edit );
 
-	Touch_AddButton( &touch.list_edit, "close", "touch_default/edit_close.tga", "touch_disableedit", 0, y, x, y + 0.1, (byte*)"\xff\xff\xff\xff" )->flags |= TOUCH_FL_NOEDIT;
-	Touch_AddButton( &touch.list_edit, "close", "#Close and save", "", x, y, x + 0.2, y + 0.1, (byte*)"\xff\xff\xff\xff" )->flags |= TOUCH_FL_NOEDIT;
-	y += 0.2;
-	Touch_AddButton( &touch.list_edit, "cancel", "touch_default/edit_reset.tga", "touch_reloadconfig", 0, y, x, y + 0.1, (byte*)"\xff\xff\xff\xff" )->flags |= TOUCH_FL_NOEDIT;
-	Touch_AddButton( &touch.list_edit, "close", "#Cancel and reset", "", x, y, x + 0.2, y + 0.1, (byte*)"\xff\xff\xff\xff" )->flags |= TOUCH_FL_NOEDIT;
-	y += 0.2;
-	touch.hidebutton = Touch_AddButton( &touch.list_edit, "showhide", "touch_default/edit_hide.tga", "touch_toggleselection", 0, y, x, y + 0.1, (byte*)"\xff\xff\xff\xff" );
+	Touch_AddButton( &touch.list_edit, "close", "touch_default/edit_close.tga", "touch_disableedit", 0, y, x, y + 0.1f, (byte*)"\xff\xff\xff\xff" )->flags |= TOUCH_FL_NOEDIT;
+	Touch_AddButton( &touch.list_edit, "close", "#Close and save", "", x, y, x + 0.2f, y + 0.1f, (byte*)"\xff\xff\xff\xff" )->flags |= TOUCH_FL_NOEDIT;
+	y += 0.2f;
+	Touch_AddButton( &touch.list_edit, "cancel", "touch_default/edit_reset.tga", "touch_reloadconfig", 0, y, x, y + 0.1f, (byte*)"\xff\xff\xff\xff" )->flags |= TOUCH_FL_NOEDIT;
+	Touch_AddButton( &touch.list_edit, "close", "#Cancel and reset", "", x, y, x + 0.2f, y + 0.1f, (byte*)"\xff\xff\xff\xff" )->flags |= TOUCH_FL_NOEDIT;
+	y += 0.2f;
+	touch.hidebutton = Touch_AddButton( &touch.list_edit, "showhide", "touch_default/edit_hide.tga", "touch_toggleselection", 0, y, x, y + 0.1f, (byte*)"\xff\xff\xff\xff" );
 	touch.hidebutton->flags |= TOUCH_FL_HIDE | TOUCH_FL_NOEDIT;
 }
 
@@ -1439,13 +1439,13 @@ static void Touch_Motion( touchEventType type, int fingerID, float x, float y, f
 	{
 		touch.wheel_amount += touch.wheel_horizontal ? dx : dy;
 
-		if( touch.wheel_amount > 0.1 )
+		if( touch.wheel_amount > 0.1f )
 		{
 			Cbuf_AddText( touch.wheel_down );
 			touch.wheel_count++;
 			touch.wheel_amount = 0;
 		}
-		if( touch.wheel_amount < -0.1 )
+		if( touch.wheel_amount < -0.1f )
 		{
 			Cbuf_AddText( touch.wheel_up );
 			touch.wheel_count++;
@@ -1499,7 +1499,7 @@ static void Touch_Motion( touchEventType type, int fingerID, float x, float y, f
 			// save angle, modify only velocity
 			dabs = sqrt( dx * dx + dy * dy );
 
-			if( dabs < 0.000001 )
+			if( dabs < 0.000001f )
 				return; // no motion, avoid division by zero
 
 			dcos = dx / dabs;
diff --git a/engine/common/gamma.c b/engine/common/gamma.c
index 8dcc2b88..103156eb 100644
--- a/engine/common/gamma.c
+++ b/engine/common/gamma.c
@@ -64,7 +64,7 @@ void BuildGammaTable( float lightgamma, float brightness )
 
 	for( i = 0; i < 256; i++ )
 	{
-		f = 255.0 * pow(( float )i / 255.0f, TEXGAMMA );
+		f = 255.0f * pow(( float )i / 255.0f, TEXGAMMA );
 		inf = (int)(f + 0.5f);
 		texgammatable[i] = bound( 0, inf, 255 );
 	}
diff --git a/engine/common/net_chan.c b/engine/common/net_chan.c
index 79ebb836..c75e1c2f 100644
--- a/engine/common/net_chan.c
+++ b/engine/common/net_chan.c
@@ -605,7 +605,7 @@ void Netchan_UpdateFlow( netchan_t *chan )
 		}
 
 		pflow->kbytespersec = (faccumulatedtime == 0.0f) ? 0.0f : bytes / faccumulatedtime / 1024.0f;
-		pflow->avgkbytespersec = pflow->avgkbytespersec * FLOW_AVG + pflow->kbytespersec * (1.0 - FLOW_AVG);
+		pflow->avgkbytespersec = pflow->avgkbytespersec * FLOW_AVG + pflow->kbytespersec * (1.0f - FLOW_AVG);
 	}
 }
 
diff --git a/engine/server/sv_client.c b/engine/server/sv_client.c
index 58ecc912..04b95001 100644
--- a/engine/server/sv_client.c
+++ b/engine/server/sv_client.c
@@ -2527,7 +2527,7 @@ void SV_ExecuteClientMessage( sv_client_t *cl, sizebuf_t *msg )
 	if( frame->senttime == 0.0f ) frame->ping_time = 0.0f;
 
 	// don't skew ping based on signon stuff either
-	if(( host.realtime - cl->connection_started ) < 2.0f && ( frame->ping_time > 0.0 ))
+	if(( host.realtime - cl->connection_started ) < 2.0f && ( frame->ping_time > 0.0f ))
 		frame->ping_time = 0.0f;
 
 	cl->latency = SV_CalcClientTime( cl );
diff --git a/engine/server/sv_main.c b/engine/server/sv_main.c
index 57a20617..37fc7cb5 100644
--- a/engine/server/sv_main.c
+++ b/engine/server/sv_main.c
@@ -579,7 +579,7 @@ qboolean SV_RunGameFrame( void )
 
 	if( sv_fps.value != 0.0f )
 	{
-		double		fps = (1.0 / (double)( sv_fps.value - 0.01 )); // FP issues
+		double		fps = (1.0 / (double)( sv_fps.value - 0.01f )); // FP issues
 		int		numFrames = 0;
 
 		while( sv.time_residual >= fps )
diff --git a/engine/server/sv_pmove.c b/engine/server/sv_pmove.c
index a02e1178..54b7cdf9 100644
--- a/engine/server/sv_pmove.c
+++ b/engine/server/sv_pmove.c
@@ -917,7 +917,7 @@ void SV_SetupMoveInterpolant( sv_client_t *cl )
 			break;
 	}
 
-	if( i == SV_UPDATE_BACKUP || finalpush - frame->senttime > 1.0 )
+	if( i == SV_UPDATE_BACKUP || finalpush - frame->senttime > 1.0f )
 	{
 		memset( svgame.interp, 0, sizeof( svgame.interp ));
 		has_update = false;
diff --git a/public/crtlib.c b/public/crtlib.c
index 97b70a10..a4bd64d5 100644
--- a/public/crtlib.c
+++ b/public/crtlib.c
@@ -21,6 +21,10 @@ GNU General Public License for more details.
 #include <time.h>
 #include "stdio.h"
 #include "crtlib.h"
+#ifdef HAVE_TGMATH_H
+#include <tgmath.h>
+#endif
+
 void Q_strnupr( const char *in, char *out, size_t size_out )
 {
 	if( size_out == 0 ) return;
@@ -652,7 +656,7 @@ char *Q_pretifymem( float value, int digitsafterdecimal )
 	digitsafterdecimal = max( digitsafterdecimal, 0 );
 
 	// if it's basically integral, don't do any decimals
-	if( fabs( value - (int)value ) < 0.00001 )
+	if( fabs( value - (int)value ) < 0.00001f )
 	{
 		Q_sprintf( val, "%i%s", (int)value, suffix );
 	}
diff --git a/public/mathlib.h b/public/mathlib.h
index 0f80e358..4a9e730e 100644
--- a/public/mathlib.h
+++ b/public/mathlib.h
@@ -33,7 +33,7 @@ GNU General Public License for more details.
 #endif
 
 #ifndef M_PI2
-#define M_PI2		(float)6.28318530717958647692
+#define M_PI2		((float)(M_PI * 2))
 #endif
 
 #define M_PI_F		((float)(M_PI))
@@ -73,8 +73,13 @@ GNU General Public License for more details.
 #define Q_floor( a )	((float)(int)(a))
 #define Q_ceil( a )		((float)(int)((a) + 1))
 #define Q_round( x, y )	(floor( x / y + 0.5f ) * y )
-#define Q_rint(x)		((x) < 0 ? ((int)((x)-0.5f)) : ((int)((x)+0.5f)))
+#define Q_rint(x)		((x) < 0.0f ? ((int)((x)-0.5f)) : ((int)((x)+0.5f)))
+
+#ifdef isnan // check for C99 isnan
+#define IS_NAN isnan
+#else
 #define IS_NAN(x)		(((*(int *)&x) & (255<<23)) == (255<<23))
+#endif
 
 #define ALIGN( x, a )	((( x ) + (( size_t )( a ) - 1 )) & ~(( size_t )( a ) - 1 ))
 
diff --git a/ref_gl/gl_rsurf.c b/ref_gl/gl_rsurf.c
index 6939dffe..e3124753 100644
--- a/ref_gl/gl_rsurf.c
+++ b/ref_gl/gl_rsurf.c
@@ -805,7 +805,7 @@ void DrawGLPoly( glpoly_t *p, float xScale, float yScale )
 		}
 		texture = R_GetTexture( glState.currentTextures[glState.activeTMU] );
 
-		flRate = abs( flConveyorSpeed ) / (float)texture->srcWidth;
+		flRate = fabs( flConveyorSpeed ) / (float)texture->srcWidth;
 		flAngle = ( flConveyorSpeed >= 0 ) ? 180 : 0;
 
 		SinCos( flAngle * ( M_PI_F / 180.0f ), &sy, &cy );
diff --git a/ref_gl/gl_studio.c b/ref_gl/gl_studio.c
index d78978dd..0eb3f297 100644
--- a/ref_gl/gl_studio.c
+++ b/ref_gl/gl_studio.c
@@ -883,7 +883,7 @@ void R_StudioMergeBones( cl_entity_t *e, model_t *m_pSubModel )
 	matrix3x4		bonematrix;
 	static vec4_t	q[MAXSTUDIOBONES];
 	static float	pos[MAXSTUDIOBONES][3];
-	double		f;
+	float		f;
 
 	if( e->curstate.sequence >=  m_pStudioHeader->numseq )
 		e->curstate.sequence = 0;
@@ -936,7 +936,7 @@ StudioSetupBones
 */
 void R_StudioSetupBones( cl_entity_t *e )
 {
-	double		f;
+	float		f;
 	mstudiobone_t	*pbones;
 	mstudioseqdesc_t	*pseqdesc;
 	mstudioanim_t	*panim;