1 files changed, 22 insertions, 0 deletions
diff --git a/vendor/crypto-bigint/src/uint/neg.rs b/vendor/crypto-bigint/src/uint/neg.rs
new file mode 100644
index 000000000..5cdba201b
--- /dev/null
+++ b/vendor/crypto-bigint/src/uint/neg.rs
@@ -0,0 +1,22 @@
+use core::ops::Neg;
+
+use crate::{CtChoice, Uint, Wrapping};
+
+impl<const LIMBS: usize> Neg for Wrapping<Uint<LIMBS>> {
+    type Output = Self;
+
+    fn neg(self) -> Self::Output {
+        let shifted = Wrapping(self.0.shl_vartime(1));
+        self - shifted
+    }
+}
+
+impl<const LIMBS: usize> Uint<LIMBS> {
+    /// Negates based on `choice` by wrapping the integer.
+    pub(crate) const fn conditional_wrapping_neg(&self, choice: CtChoice) -> Uint<LIMBS> {
+        let (shifted, _) = self.shl_1();
+        let negated_self = self.wrapping_sub(&shifted);
+
+        Uint::ct_select(self, &negated_self, choice)
+    }
+}