diff --git a/fpu/softfloat.c b/fpu/softfloat.c
index 485a006aa7..7af14e29aa 100644
--- a/fpu/softfloat.c
+++ b/fpu/softfloat.c
@@ -7492,7 +7492,7 @@ uint64_t float64_to_uint64_round_to_zero(float64 a, float_status *status)
 {
     signed char current_rounding_mode = status->float_rounding_mode;
     set_float_rounding_mode(float_round_to_zero, status);
-    int64_t v = float64_to_uint64(a, status);
+    uint64_t v = float64_to_uint64(a, status);
     set_float_rounding_mode(current_rounding_mode, status);
     return v;
 }