Add loop unrolling for MemlessPoly.cpp

1 files changed, 31 insertions, 13 deletions

diff --git a/src/MemlessPoly.cpp b/src/MemlessPoly.cpp
index dc0dd31..2a16ebe 100644
--- a/src/MemlessPoly.cpp
+++ b/src/MemlessPoly.cpp
@@ -129,7 +129,7 @@ static void apply_coeff(
         const complexf *__restrict in, size_t start, size_t stop,
         complexf *__restrict out)
 {
-    for (size_t i = start; i < stop; i++) {
+    for (size_t i = start; i < stop; i+=2) {
 
         /* Implement
            a1*x + a3*x*|x|^2 + a5*x*|x|^4 + a5*x*|x|^4 + a5*x*|x|^4 + a7*x*|x|^6
@@ -142,20 +142,38 @@ static void apply_coeff(
         // Complex polynomial, all operations are on complex values.
         // Usually this is the representation we use when speaking
         // about the real-valued passband signal that the PA receives.
-        float in_mag = std::abs(in[i]);
-        float in_2 = in_mag * in_mag;
-        float in_4 = in_2 * in_2;
-        float in_6 = in_2 * in_4;
-        float in_8 = in_4 * in_4;
-        float in_10 = in_6 * in_4;
-        out[i] = in[i] *
+        float in_1_mag = std::abs(in[i]);
+        float in_1_2 = in_1_mag * in_1_mag;
+        float in_1_4 = in_1_2 * in_1_2;
+        float in_1_6 = in_1_2 * in_1_4;
+        float in_1_8 = in_1_4 * in_1_4;
+        float in_1_10 = in_1_6 * in_1_4;
+
+        float in_2_mag = std::abs(in[i]);
+        float in_2_2 = in_2_mag * in_2_mag;
+        float in_2_4 = in_2_2 * in_2_2;
+        float in_2_6 = in_2_2 * in_2_4;
+        float in_2_8 = in_2_4 * in_2_4;
+        float in_2_10 = in_2_6 * in_2_4;
+
+        out[i+0] = in[i+0] *
             (
              coefs[0] +
-             coefs[1] * in_2 +
-             coefs[2] * in_4 +
-             coefs[3] * in_6 +
-             coefs[4] * in_8 +
-             coefs[5] * in_10
+             coefs[1] * in_1_2 +
+             coefs[2] * in_1_4 +
+             coefs[3] * in_1_6 +
+             coefs[4] * in_1_8 +
+             coefs[5] * in_1_10
+             );
+
+        out[i+1] = in[i+1] *
+            (
+             coefs[0] +
+             coefs[1] * in_2_2 +
+             coefs[2] * in_2_4 +
+             coefs[3] * in_2_6 +
+             coefs[4] * in_2_8 +
+             coefs[5] * in_2_10
              );
     }
 }