ref10: p3_batchtobytes

ed25519/ref10/ge_p3_batchtobytes.c

@@ -0,0 +1,17 @@
+#include "ge.h"
+
+// inz is ge_p3.Z pointer array. contents to .Zs will be overwritten
+void ge_p3_batchtobytes_destructive(bytes32 out[],const ge_p3 in[],fe *inz[],fe tmp[],size_t num)
+{
+  fe x;
+  fe y;
+
+  fe_batchinvert(inz,tmp,inz,num);
+
+  for (size_t i = 0;i < num;++i) {
+    fe_mul(x,in[i].X,*inz[i]);
+    fe_mul(y,in[i].Y,*inz[i]);
+    fe_tobytes(out[i],y);
+    out[i][31] ^= fe_isnegative(x) << 7;
+  }
+}