Bash ~_~ .... Azure 32-bit (+ fix BN inversion alternative path)

azure-pipelines.yml

@@ -132,12 +132,12 @@ steps:
 
       mkdir -p bin
 
-      cat < EOF > bin/gcc
+      cat << EOF > bin/gcc
       #!/bin/bash
       exec $(which gcc) -m32 "\$@"
       EOF
 
-      cat < EOF > bin/g++
+      cat << EOF > bin/g++
       #!/bin/bash
       exec $(which g++) -m32 "\$@"
       EOF

constantine/arithmetic/finite_fields_inversion.nim

@@ -161,6 +161,9 @@ func inv*(r: var Fp, a: Fp) =
   # neither for Secp256k1 nor BN curves
   # Performance is slower than GCD
   # To be revisited with faster squaring/multiplications
+  when false: # Fp.C.canUse_BN_AddchainInversion():
+    r.invmod_addchain_bn(a)
+  else:
     r.mres.steinsGCD(a.mres, Fp.C.getR2modP(), Fp.C.Mod, Fp.C.getPrimePlus1div2())
 
 func inv*(a: var Fp) =
@@ -175,5 +178,5 @@ func inv*(a: var Fp) =
   # Performance is slower than GCD
   # To be revisited with faster squaring/multiplications
   var t: typeof(a) # TODO: zero-init needed?
-  t.mres.steinsGCD(a.mres, Fp.C.getR2modP(), Fp.C.Mod, Fp.C.getPrimePlus1div2())
+  t.inv(a)
   a = t

constantine/config/curves_parser.nim

@@ -346,6 +346,14 @@ proc genMainConstants(defs: var seq[CurveParams]): NimNode =
           exported($curve & "_BN_can_use_addchain_inversion"),
           newLit true
         )
+        curveExtraStmts.add newConstStmt(
+          exported($curve & "_BN_param_u"),
+          newCall(
+            bindSym"fromHex",
+            nnkBracketExpr.newTree(bindSym"BigInt", curveDef.bn_u_bitwidth),
+            curveDef.bn_u
+          )
+        )
       else:
         curveExtraStmts.add newConstStmt(
           exported($curve & "_BN_can_use_addchain_inversion"),