嘗試在SSE編程中使用和掩碼添加__m128

Question

我想使用比較操作的結果添加到SSE變量。我剛剛意識到，使用_mm_cmplt_ps操作時，如果結果爲真則返回一個NAN因爲0xffffffff的無法表示這是對我沒有用的：

__m128 va; 
__m128 vb; 
__m128 result =_mm_set1_ps(0.0f); 
vb = _mm_cmplt_ps(va,vb); 
result = _mm_add_ps(result,vb); // problem is that I would like to convert vb to 1.0's and 0.0's 

Answer 1

你可以只應用比較掩碼到1.0值的向量，例如

__m128 va, vb; 
__m128 vcmp = _mm_cmplt_ps(va, vb); 
__m128 vresult = _mm_and_ps(_mm_set1_ps(1.0f), vcmp);