[tests] add mini test case for MSM on Nvidia

tests/gpu/t_msm.nim

@@ -0,0 +1,68 @@
+# Constantine
+# Copyright (c) 2018-2019    Status Research & Development GmbH
+# Copyright (c) 2020-Present Mamy André-Ratsimbazafy
+# Licensed and distributed under either of
+#   * MIT license (license terms in the root directory or at http://opensource.org/licenses/MIT).
+#   * Apache v2 license (license terms in the root directory or at http://www.apache.org/licenses/LICENSE-2.0).
+# at your option. This file may not be copied, modified, or distributed except according to those terms.
+
+import
+  # Internal
+  constantine/named/algebras,
+  constantine/math/io/[io_bigints, io_fields, io_ec],
+  constantine/math/arithmetic,
+  constantine/math/elliptic/[ec_shortweierstrass_affine, ec_shortweierstrass_jacobian, ec_multi_scalar_mul],
+  constantine/platforms/abstractions,
+  constantine/platforms/llvm/llvm,
+  constantine/math_compiler/[ir, pub_fields, pub_curves_jacobian, codegen_nvidia, impl_fields_globals],
+  # Test utilities
+  helpers/prng_unsafe
+
+type
+  EC = EC_ShortW_Jac[Fp[BN254_Snarks], G1]
+  ECAff = EC_ShortW_Aff[Fp[BN254_Snarks], G1]
+const wordSize = 32
+
+# 2 EC points
+let x = "0x2ef34a5db00ff691849861d49415d8081d9d0e10cba33b57b2dd1f37f13eeee0"
+let y = "0x2beb0d0d6115007676f30bcc462fe814bf81198848f139621a3e9fa454fe8e6a"
+let pt = ECAff.fromHex(x, y)
+echo pt.toHex()
+
+let x2 = "0x226c85cf65f4596a77da7d247310a81ac9aa9220e819e3ef23b6cbe0218ce272"
+let y2 = "0xf53265870f65aa18bded3ccb9c62a4d8b060a32a05a75d455710bce95a991df"
+let pt2 = ECAff.fromHex(x2, y2)
+
+# 2 coefficients
+let a = Fr[BN254_Snarks].fromUInt(1'u32)
+let b = Fr[BN254_Snarks].fromHex("0x2beb0d0d6115007676f30bcc462fe814bf81198848f139621a3e9fa454fe8e6a")
+
+proc fromField[BigInt](x: FF): BigInt =
+  result.fromField(x)
+
+type CB = Fr[BN254_Snarks].getBigInt()
+
+template toPOA(x): untyped = cast[ptr UncheckedArray[x[0].typeof]](x[0].addr)
+
+let bN = fromField[CB](b) # convert to BigInt to go from Montgomery rep to canonical rep
+let coefs = [bN, bN]
+
+let points = [pt, pt2]
+
+block MSM:
+  # Codegen
+  # -------------------------
+  let nv = initNvAsm(EC, wordSize)
+  let kernel = nv.compile(nv.asy.genEcMSM(nv.cd, 3, coefs.len))
+
+  # For CPU:
+  var rCPU: EC
+  rCPU.multiScalarMul_reference_vartime(@coefs, @points)
+
+  # For GPU:
+  var rGPU: EC
+  kernel.execCuda(res = rGPU, inputs = (coefs, points))
+  echo "CPU: ", rCPU.toHex()
+  echo "GPU: ", rGPU.toHex()
+  # Verify CPU and GPU agree
+  doAssert bool(rCPU == rGPU)