尝试在 SSE 编程中使用和掩码添加 __m128 [英] Trying to add an __m128 using an and mask in SSE programming

问题描述

我正在尝试使用比较操作的结果添加到 SSE 变量.我刚刚意识到，当使用 _mm_cmplt_ps 操作时，如果结果为真，它会返回一个 NAN，因为无法表示 0xffffffff，这对我没有用:

I am trying to use the result of a compare operation to add to an SSE variable. I have just realised that when using the _mm_cmplt_ps operation if the result is true it returns a NAN because 0xffffffff can't be represented which is of no use to me:

__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

推荐答案

您可以将比较掩码应用于 1.0 值的向量，例如

You can just apply the comparison mask to a vector of 1.0 values, e.g.

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

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