HLSL 5.0的语法有关问题

HLSL 5.0的语法问题
Assembly code

struct GSOutput
{
int4 Pos : Position;
int4 Color : Color;
int4 Texcoord : Texcoord;
};

[maxvertexcount(1)]
void gsBase (inout PointStream<GSOutput> OutputStream, inout PointStream<GSOutput> OutputStream1)
{
GSOutput output;
output.Pos = int4(1,2,3,4);
output.Color = int4(5,6,7,8);
output.Texcoord = int4(9,10,11,12);
OutputStream.Append(output);

output.Pos = int4(1,2,3,4);
    output.Color = int4(5,6,7,8);
output.Texcoord = int4(9,10,11,12);
OutputStream1.Append(output);
};


GeometryShader pGSComp = CompileShader(gs_5_0, gsBase());
GeometryShader pGSwSO = ConstructGSWithSO(pGSComp, "0:Position.xy; 1:Position.zw; 2:Color.xy", 
                                                   "3:Texcoord.xyzw; 3:$SKIP.x;", NULL, NULL, 1);

// The following two passes perform the same operation
technique11 SOPoints
{
    pass 
    {
        SetGeometryShader(ConstructGSWithSO(pGSComp, "0:Position.xy; 1:Position.zw; 2:Color.xy", 
                                                     "3:Texcoord.xyzw; 3:$SKIP.x;", NULL, NULL, 1));
    }
    pass 
    {
        SetGeometryShader(pGSwSO);
    }
}



有这么一段话:
There is one special Semantic, labeled "$SKIP" which indicates an empty semantic, leaving the corresponding memory in the stream out buffer untouched. The $SKIP semantic cannot have a SemanticIndex, but can have a Mask.

具体情况请参考:http://msdn.microsoft.com/en-us/library/windows/desktop/ff476168%28v=vs.85%29.aspx

这段话似懂非懂,有没有明白的人给详细地说明一下。关键是说说$SKIP达成什么样的效果。

------解决方案--------------------
。。5.0 新出的高端显卡才支持吧
------解决方案--------------------
好吧,关于这个我啥都看不懂