[pixel shader]
uniform float4 x;

float4 main() : sv_target
{
    return log2(x);
}

[test]
uniform 0 float4 2.0 4.0 5.0 0.4
draw quad
probe (0, 0) rgba (1.0, 2.0, 2.32192802, -1.32192802) 1

[pixel shader]
uniform float4 x;

float4 main() : sv_target
{
    return log10(x);
}

[test]
uniform 0 float4 10.0 100.0 1.0 0.1
draw quad
probe (0, 0) rgba (1.0, 2.0, 0.0, -1.0) 1

[pixel shader]
uniform float4 x;

float4 main() : sv_target
{
    return log(x);
}

[test]
uniform 0 float4 3.0 10.0 1.0 0.1
draw quad
probe (0, 0) rgba (1.0986123, 2.302585, 0.0, -2.302585) 2