diff --git a/src/d2s.rs b/src/d2s.rs
index 392577a..18c49a5 100644
--- a/src/d2s.rs
+++ b/src/d2s.rs
@@ -86,7 +86,7 @@ pub struct FloatingDecimal64 {
 }
 
 #[cfg_attr(feature = "no-panic", inline)]
-pub fn d2d(ieee_mantissa: u64, ieee_exponent: u32) -> FloatingDecimal64 {
+pub unsafe fn d2d(ieee_mantissa: u64, ieee_exponent: u32) -> FloatingDecimal64 {
     let (e2, m2) = if ieee_exponent == 0 {
         (
             // We subtract 2 so that the bounds computation has 2 additional bits.
diff --git a/src/pretty/mod.rs b/src/pretty/mod.rs
index 6977339..f950f7b 100644
--- a/src/pretty/mod.rs
+++ b/src/pretty/mod.rs
@@ -68,7 +68,7 @@ pub unsafe fn format64(f: f64, result: *mut u8) -> usize {
         index += 1;
     }
 
-    let v = d2d(ieee_mantissa, ieee_exponent);
+    let v = unsafe { d2d(ieee_mantissa, ieee_exponent) };
 
     let length = d2s::decimal_length17(v.mantissa) as isize;
     let k = v.exponent as isize;