commit edd171a6f420caed1c1b8c5b08b6163a4909fbe9
Author: David Sorber <david.sorber@gmail.com>
Date:   Wed Jan 9 07:17:38 2019 -0500

    Adding packed single precision (aka "ps") intrinsic test. This includes
    useful horizontal sum and horizontal min/max routines.

diff --git a/software/misc/ps_test.cc b/software/misc/ps_test.cc
new file mode 100644
index 0000000..cb7687e
--- /dev/null
+++ b/software/misc/ps_test.cc
@@ -0,0 +1,94 @@
+#include <iostream>
+
+#include <x86intrin.h>
+
+// Return horizontal sum for 128 bit packed float vector
+float hsum_ps_sse3(__m128 val) 
+{
+    __m128 shuf = _mm_movehdup_ps(val); // broadcast elements 3,1 to 2,0
+    __m128 sums = _mm_add_ps(val, shuf);
+    shuf        = _mm_movehl_ps(shuf, sums);    // high half -> low half
+    sums        = _mm_add_ss(sums, shuf);
+    return        _mm_cvtss_f32(sums);
+}
+
+// Return horizontal sum for 256 bit packed float vector
+// https://stackoverflow.com/a/35270026/73878 -- Peter Cordes is da man
+float hsum256_ps_avx(__m256 val) 
+{
+    __m128 vlow  = _mm256_castps256_ps128(val);
+    __m128 vhigh = _mm256_extractf128_ps(val, 1);   // high 128
+           vlow  = _mm_add_ps(vlow, vhigh);         // add the low 128
+    return hsum_ps_sse3(vlow);  // and inline the sse3 version, which is optimal for AVX
+}
+
+void print_debug(__m256 val)
+{
+    float temp[8];
+    
+    _mm256_store_ps(temp, val);
+    std::cout << "DEBUG: " 
+              << temp[0] << " -- " << temp[1] << " -- "
+              << temp[2] << " -- " << temp[3] << " -- "
+              << temp[4] << " -- " << temp[5] << " -- "
+              << temp[6] << " -- " << temp[7] << std::endl;
+}
+
+// Return max value across (i.e. horizontally) vector
+// Algorithm came from here: https://stackoverflow.com/a/9798369/73878
+float max_ps_avx(__m256 val)
+{
+    __m256 m0 = _mm256_permute2f128_ps(val, val, 1); // Permute 128-bit values   
+    __m256 m1 = _mm256_max_ps(val, m0); // Compute max of 4 sets
+    
+    __m256 m2 = _mm256_permute_ps(m1, 0x4E); // Permute max values
+    __m256 m3 = _mm256_max_ps(m1, m2); // Compute max of 2 sets
+    
+    __m256 m4 = _mm256_permute_ps(m3, 0x3B); // Permute max values    
+    __m256 m  = _mm256_max_ps(m3, m4);  // Compute (final) max
+    
+    return _mm_cvtss_f32(_mm256_extractf128_ps(m, 0));
+}
+
+// Return min value across (i.e. horizontally) vector
+// Algorithm came from here: https://stackoverflow.com/a/9798369/73878
+float min_ps_avx(__m256 val)
+{
+    __m256 m0 = _mm256_permute2f128_ps(val, val, 1); // Permute 128-bit values   
+    __m256 m1 = _mm256_min_ps(val, m0); // Compute min of 4 sets
+    
+    __m256 m2 = _mm256_permute_ps(m1, 0x4E); // Permute max values
+    __m256 m3 = _mm256_min_ps(m1, m2); // Compute min of 2 sets
+    
+    __m256 m4 = _mm256_permute_ps(m3, 0x3B); // Permute max values    
+    __m256 m  = _mm256_min_ps(m3, m4);  // Compute (final) min
+    
+    return _mm_cvtss_f32(_mm256_extractf128_ps(m, 0));
+}
+
+// g++ -std=c++11 -O3 -mavx -o ps_test ps_test.cc
+int main(int argc, char** argv)
+{
+    std::cout << "Packed Float (PS) Test\n" << std::endl;
+    
+    float raw_data[8] = {1.0, 2.0, -3.0, 4.0, 5.0, -6.0, 7.0 , 8.0};
+    
+    // Generate signmask
+    __m256 SIGNMASK = _mm256_castsi256_ps(_mm256_set1_epi32(0x80000000));
+    
+    // Load data
+    __m256 data = _mm256_loadu_ps(raw_data);
+    
+    // Take absolute value of data
+    __m256 abs_data = _mm256_andnot_ps(SIGNMASK, data);
+    
+    // Sum data
+    float total = hsum256_ps_avx(data);
+    float total_abs = hsum256_ps_avx(abs_data);
+    
+    std::cout << "Total: " << total << " -- " << total_abs << std::endl;
+    std::cout << "  Max: " << max_ps_avx(abs_data) << std::endl;
+    std::cout << "  Min: " << min_ps_avx(abs_data) << std::endl;
+    
+    return 0;
+}