1 files changed, 35 insertions, 0 deletions
diff --git a/sumsq_mmx.c b/sumsq_mmx.c
new file mode 100644
index 0000000..e766831
--- /dev/null
+++ b/sumsq_mmx.c
@@ -0,0 +1,35 @@
+/* Compute the sum of the squares of a vector of signed shorts
+
+ *  MMX-assisted version (also used on SSE)
+
+ * The SSE2 and MMX assist routines both operate on multiples of
+ * 8 words; they differ only in their alignment requirements (8 bytes
+ * for MMX, 16 bytes for SSE2)
+
+ * Copyright 2004 Phil Karn, KA9Q
+ * May be used under the terms of the GNU Lesser Public License (LGPL)
+ */
+
+long long sumsq_mmx_assist(signed short *,int);
+
+long long sumsq_mmx(signed short *in,int cnt){
+  long long sum = 0;
+
+  /* Handle stuff before the next 8-byte boundary */
+  while(((int)in & 7) != 0 && cnt != 0){
+    sum += (long)in[0] * in[0];
+    in++;
+    cnt--;
+  }
+  sum += sumsq_mmx_assist(in,cnt);
+  in += cnt & ~7;
+  cnt &= 7;
+
+  /* Handle up to 7 words at end */
+  while(cnt != 0){
+    sum += (long)in[0] * in[0];
+    in++;
+    cnt--;
+  }
+  return sum;
+}