uniform half2x2 testMatrix2x2;  // equals (1, 2, 3, 4)
uniform half4 colorGreen, colorRed;

half4 main(float2 coords) {
    half4 infiniteValue = half4(testMatrix2x2) / colorGreen.r;
    half4   finiteValue = half4(testMatrix2x2) / colorGreen.g;

    return (    (isinf(infiniteValue.x))     &&
             all(isinf(infiniteValue.xy))    &&
             all(isinf(infiniteValue.xyz))   &&
             all(isinf(infiniteValue.xyzw))  &&
            !   (isinf(finiteValue  .x))     &&
            !any(isinf(finiteValue  .xy))    &&
            !any(isinf(finiteValue  .xyz))   &&
            !any(isinf(finiteValue  .xyzw))) ? colorGreen : colorRed;
}