diff --git a/src/int/shift.rs b/src/int/shift.rs
index 080de2a14..c90cf1de3 100644
--- a/src/int/shift.rs
+++ b/src/int/shift.rs
@@ -78,8 +78,8 @@ intrinsics! {
     #[avr_skip]
     #[maybe_use_optimized_c_shim]
     #[arm_aeabi_alias = __aeabi_llsl]
-    pub extern "C" fn __ashldi3(a: u64, b: u32) -> u64 {
-        a.ashl(b)
+    pub extern "C" fn __ashldi3(a: u64, b: core::ffi::c_uint) -> u64 {
+        a.ashl(b as u32)
     }
 
     #[avr_skip]
@@ -96,8 +96,8 @@ intrinsics! {
     #[avr_skip]
     #[maybe_use_optimized_c_shim]
     #[arm_aeabi_alias = __aeabi_lasr]
-    pub extern "C" fn __ashrdi3(a: i64, b: u32) -> i64 {
-        a.ashr(b)
+    pub extern "C" fn __ashrdi3(a: i64, b: core::ffi::c_uint) -> i64 {
+        a.ashr(b as u32)
     }
 
     #[avr_skip]
@@ -114,8 +114,8 @@ intrinsics! {
     #[avr_skip]
     #[maybe_use_optimized_c_shim]
     #[arm_aeabi_alias = __aeabi_llsr]
-    pub extern "C" fn __lshrdi3(a: u64, b: u32) -> u64 {
-        a.lshr(b)
+    pub extern "C" fn __lshrdi3(a: u64, b: core::ffi::c_uint) -> u64 {
+        a.lshr(b as u32)
     }
 
     #[avr_skip]