Coq: add signed bitvector to integer function that doesn't need >0 constraint

1 files changed, 3 insertions, 0 deletions

diff --git a/lib/coq/Sail2_operators_mwords.v b/lib/coq/Sail2_operators_mwords.v
index 5a5f130c..cca52c1d 100644
--- a/lib/coq/Sail2_operators_mwords.v
+++ b/lib/coq/Sail2_operators_mwords.v
@@ -291,6 +291,9 @@ rewrite <- Z.lt_le_pred.
 auto.
 Defined.
 
+Definition sint0 {a} `{ArithFact (a >= 0)} (x : mword a) : Z :=
+  if sumbool_of_bool (Z.eqb a 0) then 0 else projT1 (sint x).
+
 Lemma length_list_pos : forall {A} {l:list A}, length_list l >= 0.
 unfold length_list.
 auto with zarith.