add missing files, 2 stage batch pack

ed25519/amd64-64-24k/fe25519_batchinvert.c

@@ -0,0 +1,26 @@
+#include "fe25519.h"
+
+// tmp MUST != out
+// in MAY == out
+void fe25519_batchinvert(fe25519 *out[],fe25519 tmp[],fe25519 * const in[], size_t num)
+{
+  fe25519 acc;
+  fe25519 tmpacc;
+  size_t i;
+
+  fe25519_setint(&acc,1);
+
+  for (i = 0;i < num;++i) {
+    tmp[i] = acc;
+    fe25519_mul(&acc,&acc,in[i]);
+  }
+
+  fe25519_invert(&acc,&acc);
+
+  i = num;
+  while (i--) {
+    fe25519_mul(&tmpacc,&acc,in[i]);
+    fe25519_mul(out[i],&acc,&tmp[i]);
+    acc = tmpacc;
+  }
+}