[pixel shader todo(sm<4)]
float4 v;

float4 main() : sv_target
{
    float4 ip;
    return modf(v, ip);
}

[test]
uniform 0 float4 1.2 1.7 -1.2 -1.7
todo(sm<4) draw quad
probe (0, 0) rgba (0.2, 0.7, -0.2, -0.7) 4

[pixel shader todo(sm<4)]
float4 v;

float4 main() : sv_target
{
    float4 ip;
    modf(v, ip);
    return ip;
}

[test]
uniform 0 float4 1.2 2.7 -1.2 -2.7
todo(sm<4) draw quad
probe (0, 0) rgba (1.0, 2.0, -1.0, -2.0)