support bn128 and circom

.gitignore

@@ -14,4 +14,5 @@ docs/**bench**
 
 **/*/libposeidon-permute-c-mac.a
 **/*/go-iden3-crypto/
+node_modules
 .vscode

circom/circuits/goldilocks.circom

@@ -0,0 +1,35 @@
+pragma circom 2.0.9;
+
+template GlExp() {
+  signal input x;
+  signal input n;
+  signal output out;
+
+  signal e2[65];
+  signal temp1[64];
+  signal temp2[64];
+  signal mul[65];
+  mul[0] <== 1;
+  e2[0] <== x;
+  for (var i = 0; i < 64; i++) {
+    temp1[i] <-- (n >> i) & 1;
+    temp2[i] <== e2[i] * temp1[i] + 1 - temp1[i];
+    mul[i + 1] <== mul[i] * temp2[i];
+    e2[i + 1] <== e2[i] * e2[i];
+  }
+
+  out <== mul[64];
+}
+
+template GlExtMul() {
+  signal input a[2];
+  signal input b[2];
+  signal output out[2];
+
+  var W = 7;
+  signal tmp1 <== W * a[1] * b[1];
+  signal tmp2 <== a[1] * b[0];
+
+  out[0] <== a[0] * b[0] + tmp1;
+  out[1] <== a[0] * b[1] + tmp2;
+}