Whats so slow here? (Triangle fill routine)

Graphics 1024, 768, 32, 2
SetBuffer BackBuffer()

;Texture
Global Tex = CreateBank(16 * 16 * 4)
img = LoadImage("Texture.png")
LockBuffer ImageBuffer(img)
For x = 0 To 15
	For y = 0 To 15
		PokeFloat Tex, (x * 16 + y) * 4, ReadPixelFast(x, y, ImageBuffer(img))
	Next
Next
UnlockBuffer ImageBuffer(img)
FreeImage img

While Not KeyHit(1)
	mx = MouseX()
	my = MouseY()
	
	Cls
	LockBuffer()
	FillTri(120, 120, 0, 0, 970, 100, 16, 0, mx, my, 16, 16);, 0, 0, 16, 0, 16, 16)
	FillTri(120, 120, 0, 0, 100, 600, 0, 16, mx, my, 16, 16);, 0, 0, 0, 16, 16, 16)
	UnlockBuffer()
	
	Text 10, 10, "FPS: " + GetFPS()
	Flip 0
Wend
End

Global FPS, FPS_temp, FPS_time
Function GetFPS()
ctime = MilliSecs()
FPS_temp = FPS_temp + 1
If ctime - FPS_time > 500 Then
	FPS = FPS_temp * 2
	FPS_temp = 0
	FPS_time = ctime
EndIf
Return FPS
End Function

Function FillTri(p1x, p1y, p1u, p1v, p2x, p2y, p2u, p2v, p3x, p3y, p3u, p3v)
p1u = p1u Shl 16
p1v = p1v Shl 16
p2u = p2u Shl 16
p2v = p2v Shl 16
p3u = p3u Shl 16
p3v = p3v Shl 16
If p1y > p2y Then
	ptx = p1x
	pty = p1y
	ptu = p1u
	ptv = p1v
	
	p1x = p2x
	p1y = p2y
	p1u = p2u
	p1v = p2v
	
	p2x = ptx
	p2y = pty
	p2u = ptu
	p2v = ptv
EndIf
If p2y > p3y Then
	ptx = p2x
	pty = p2y
	ptu = p2u
	ptv = p2v
	
	p2x = p3x
	p2y = p3y
	p2u = p3u
	p2v = p3v
	
	p3x = ptx
	p3y = pty
	p3u = ptu
	p3v = ptv
	If p1y > p2y Then
		ptx = p1x
		pty = p1y
		ptu = p1u
		ptv = p1v
		
		p1x = p2x
		p1y = p2y
		p1u = p2u
		p1v = p2v
		
		p2x = ptx
		p2y = pty
		p2u = ptu
		p2v = ptv
	EndIf
EndIf
If p1y <> p2y Then
	For y = p1y To p2y
		x1 = vgliIntp(y, p1y, p3y, p1x, p3x)
		u1 = vgliIntp(y, p1y, p3y, p1u, p3u)
		v1 = vgliIntp(y, p1y, p3y, p1v, p3v)
		x2 = vgliIntp(y, p1y, p2y, p1x, p2x)
		u2 = vgliIntp(y, p1y, p2y, p1u, p2u)
		v2 = vgliIntp(y, p1y, p2y, p1v, p2v)
		FillTriLine(x1, u1, v1, x2, u2, v2, y)
	Next
EndIf
If p2y <> p3y Then
	For y = p2y To p3y
		x1 = vgliIntp(y, p1y, p3y, p1x, p3x)
		u1 = vgliIntp(y, p1y, p3y, p1u, p3u)
		v1 = vgliIntp(y, p1y, p3y, p1v, p3v)
		x2 = vgliIntp(y, p2y, p3y, p2x, p3x)
		u2 = vgliIntp(y, p2y, p3y, p2u, p3u)
		v2 = vgliIntp(y, p2y, p3y, p2v, p3v)
		FillTriLine(x1, u1, v1, x2, u2, v2, y)
	Next
EndIf
End Function

Function FillTriLine(p1x, p1u, p1v, p2x, p2u, p2v, y)
If p1x = p2x Then Return
If p1x > p2x Then
	tx = p1x
	tu = p1u
	tv = p1v
	p1x = p2x
	p1u = p2u
	p1v = p2v
	p2x = tx
	p2u = tu
	p2v = tv
EndIf
iu = (p2u - p1u) / (p2x - p1x)
iv = (p2v - p1v) / (p2x - p1x)
For x = p1x To p2x
	u = (p1u + (x - p1x) * iu) Shr 16
	v = (p1v + (x - p1x) * iv) Shr 16
	WritePixelFast x, y, PeekFloat(Tex, (v * 16 + u) * 4)
Next
End Function

Function vgliIntp#(value#, vMin#, vMax#, retMin#, retMax#)
Return retMin# + (value# - vMin#) * (retMax# - retMin#) / (vMax# - vMin#)
End Function

thank you for your help, i used shr and shl instead of floats and replaced speed critical functions with their content.

thanks for help :)