1 files changed, 21 insertions, 0 deletions
diff --git a/library/compiler-builtins/libm/src/math/frexp.rs b/library/compiler-builtins/libm/src/math/frexp.rs
new file mode 100644
index 00000000000..de7a64fdae1
--- /dev/null
+++ b/library/compiler-builtins/libm/src/math/frexp.rs
@@ -0,0 +1,21 @@
+#[cfg_attr(all(test, assert_no_panic), no_panic::no_panic)]
+pub fn frexp(x: f64) -> (f64, i32) {
+    let mut y = x.to_bits();
+    let ee = ((y >> 52) & 0x7ff) as i32;
+
+    if ee == 0 {
+        if x != 0.0 {
+            let x1p64 = f64::from_bits(0x43f0000000000000);
+            let (x, e) = frexp(x * x1p64);
+            return (x, e - 64);
+        }
+        return (x, 0);
+    } else if ee == 0x7ff {
+        return (x, 0);
+    }
+
+    let e = ee - 0x3fe;
+    y &= 0x800fffffffffffff;
+    y |= 0x3fe0000000000000;
+    return (f64::from_bits(y), e);
+}