1 files changed, 54 insertions, 0 deletions
diff --git a/vere/pkg/noun/jets/e/ed_scalarmult.c b/vere/pkg/noun/jets/e/ed_scalarmult.c
new file mode 100644
index 0000000..8585c29
--- /dev/null
+++ b/vere/pkg/noun/jets/e/ed_scalarmult.c
@@ -0,0 +1,54 @@
+/// @file
+
+#include "jets/q.h"
+#include "jets/w.h"
+
+#include "noun.h"
+#include "urcrypt.h"
+
+  static u3_atom
+  _cqee_scalarmult(u3_atom a,
+                  u3_atom b)
+  {
+    c3_y a_y[32], b_y[32], out_y[32];
+    if (0 != u3r_bytes_fit(32, b_y, b)) {
+      return u3m_bail(c3__exit);
+    }
+
+    c3_w met_w = u3r_met(3, a);
+    // scalarmult expects a_y[31] <= 127
+    if ( (32 < met_w) ||
+         ( (32 == met_w) &&
+           (127 < u3r_byte(31, a)) )
+        ) {
+      u3_noun a_recs = u3qee_recs(a);
+      u3r_bytes(0, 32, a_y, a_recs);
+      u3z(a_recs);
+    } else {
+      u3r_bytes(0, 32, a_y, a);
+    }
+
+    if ( (0 != urcrypt_ed_scalarmult(a_y, b_y, out_y)) ) {
+      // at this point, will only fail if b is bad point
+      return u3m_bail(c3__exit);
+    }
+    else {
+      return u3i_bytes(32, out_y);
+    }
+  }
+
+  u3_noun
+  u3wee_scalarmult(u3_noun cor)
+  {
+    u3_noun a, b;
+
+    if ( (c3n == u3r_mean(cor, u3x_sam_2, &a,
+                               u3x_sam_3, &b, 0)) ||
+         (c3n == u3ud(a)) ||
+         (c3n == u3ud(b)) )
+    {
+      return u3m_bail(c3__exit);
+    } else {
+      return _cqee_scalarmult(a, b);
+    }
+  }