[pixel shader]
float4 main(uniform float4 a, uniform float2 b) : SV_TARGET
{
    float u = a.x, v = a.y, w = a.z, x = a.w, y = b.x, z = b.y;
    return float4(x * y - z / w + --u / -v,
            z * x / y + w / -v,
            u + v - w,
            x / y / w);
}

[test]
uniform 0 float4 2.5 0.3 0.2 0.7
uniform 4 float4 0.1 1.5 0.0 0.0
draw quad
probe all rgba (-12.43, 9.833333, 1.6, 35.0) 1