diff --git a/constantine.nimble b/constantine.nimble
index b5fe831..18ad3f1 100644
--- a/constantine.nimble
+++ b/constantine.nimble
@@ -302,7 +302,7 @@ const testDesc: seq[tuple[path: string, useGMP: bool]] = @[
   ("tests/math_bigints/t_io_bigints.nim", false),
   # ("tests/math_bigints/t_bigints.nim", false),
   # ("tests/math_bigints/t_bigints_multimod.nim", false),
-  # ("tests/math_bigints/t_bigints_mul_vs_gmp.nim", true),
+  ("tests/math_bigints/t_bigints_mul_vs_gmp.nim", true),
   # ("tests/math_bigints/t_bigints_mul_high_words_vs_gmp.nim", true),
 
   # Big ints - arbitrary precision
diff --git a/constantine/math/arithmetic/assembly/limbs_asm_mul_x86.nim b/constantine/math/arithmetic/assembly/limbs_asm_mul_x86.nim
index 4ee1631..358f0bd 100644
--- a/constantine/math/arithmetic/assembly/limbs_asm_mul_x86.nim
+++ b/constantine/math/arithmetic/assembly/limbs_asm_mul_x86.nim
@@ -39,7 +39,7 @@ macro mul_gen[rLen, aLen, bLen: static int](r_PIR: var Limbs[rLen], a_MEM: Limbs
   let
     r = asmArray(r_PIR, rLen, PointerInReg, asmInputOutputEarlyClobber, memIndirect = memWrite) # MemOffsettable is the better constraint but compilers say it is impossible. Use early clobber to ensure it is not affected by constant propagation at slight pessimization (reloading it).
     a = asmArray(a_MEM, aLen, MemOffsettable, asmInput)
-    b = asmArray(b_MEM, aLen, MemOffsettable, asmInput)
+    b = asmArray(b_MEM, bLen, MemOffsettable, asmInput)
 
     tSym = ident"t"
     t = asmValue(tSym, Reg, asmOutputEarlyClobber)
diff --git a/tests/math_bigints/t_bigints_mul_high_words_vs_gmp.nim b/tests/math_bigints/t_bigints_mul_high_words_vs_gmp.nim
index 0cd2363..eecff7a 100644
--- a/tests/math_bigints/t_bigints_mul_high_words_vs_gmp.nim
+++ b/tests/math_bigints/t_bigints_mul_high_words_vs_gmp.nim
@@ -63,6 +63,10 @@ proc main() =
   mpz_init(r)
   mpz_init(a)
   mpz_init(b)
+  defer:
+    mpz_clear(b)
+    mpz_clear(a)
+    mpz_clear(r)
 
   testRandomModSizes(12, rBits, aBits, bBits, wordsStartIndex):
     # echo "--------------------------------------------------------------------------------"
diff --git a/tests/math_bigints/t_bigints_mul_vs_gmp.nim b/tests/math_bigints/t_bigints_mul_vs_gmp.nim
index 083f9c3..eeb17de 100644
--- a/tests/math_bigints/t_bigints_mul_vs_gmp.nim
+++ b/tests/math_bigints/t_bigints_mul_vs_gmp.nim
@@ -16,6 +16,7 @@ import
   ../../constantine/math/arithmetic,
   ../../constantine/platforms/abstractions,
   # Test utilities
+  ../../constantine/platforms/codecs,
   ../../helpers/prng_unsafe
 
 echo "\n------------------------------------------------------\n"
@@ -60,6 +61,10 @@ proc main() =
   mpz_init(r)
   mpz_init(a)
   mpz_init(b)
+  defer:
+    mpz_clear(b)
+    mpz_clear(a)
+    mpz_clear(r)
 
   testRandomModSizes(12, rBits, aBits, bBits):
     # echo "--------------------------------------------------------------------------------"
@@ -117,8 +122,8 @@ proc main() =
       discard mpz_export(aBuf[0].addr, aW.addr, GMP_MostSignificantWordFirst, 1, GMP_WordNativeEndian, 0, a)
       discard mpz_export(bBuf[0].addr, bW.addr, GMP_MostSignificantWordFirst, 1, GMP_WordNativeEndian, 0, b)
       "\nMultiplication with operands\n" &
-      "  a (" & align($aBits, 4) & "-bit):   " & aBuf.toHex & "\n" &
-      "  b (" & align($bBits, 4) & "-bit):   " & bBuf.toHex & "\n" &
+      "  a (" & align($aBits, 4) & "-bit):   " & aBuf.toHex() & "\n" &
+      "  b (" & align($bBits, 4) & "-bit):   " & bBuf.toHex() & "\n" &
       "into r of size " & align($rBits, 4) & "-bit failed:" & "\n" &
       "  GMP:            " & rGMP.toHex() & "\n" &
       "  Constantine:    " & rConstantine.toHex() & "\n" &