1 files changed, 34 insertions, 0 deletions
diff --git a/library/compiler-builtins/libm/src/math/modff.rs b/library/compiler-builtins/libm/src/math/modff.rs
new file mode 100644
index 00000000000..90c6bca7d8d
--- /dev/null
+++ b/library/compiler-builtins/libm/src/math/modff.rs
@@ -0,0 +1,34 @@
+#[cfg_attr(all(test, assert_no_panic), no_panic::no_panic)]
+pub fn modff(x: f32) -> (f32, f32) {
+    let rv2: f32;
+    let mut u: u32 = x.to_bits();
+    let mask: u32;
+    let e = (((u >> 23) & 0xff) as i32) - 0x7f;
+
+    /* no fractional part */
+    if e >= 23 {
+        rv2 = x;
+        if e == 0x80 && (u << 9) != 0 {
+            /* nan */
+            return (x, rv2);
+        }
+        u &= 0x80000000;
+        return (f32::from_bits(u), rv2);
+    }
+    /* no integral part */
+    if e < 0 {
+        u &= 0x80000000;
+        rv2 = f32::from_bits(u);
+        return (x, rv2);
+    }
+
+    mask = 0x007fffff >> e;
+    if (u & mask) == 0 {
+        rv2 = x;
+        u &= 0x80000000;
+        return (f32::from_bits(u), rv2);
+    }
+    u &= !mask;
+    rv2 = f32::from_bits(u);
+    return (x - rv2, rv2);
+}