1 files changed, 37 insertions, 0 deletions
diff --git a/sysdeps/ieee754/dbl-64/w_ilogb-impl.h b/sysdeps/ieee754/dbl-64/w_ilogb-impl.h
new file mode 100644
index 0000000..c919735
--- /dev/null
+++ b/sysdeps/ieee754/dbl-64/w_ilogb-impl.h
@@ -0,0 +1,37 @@
+/* Get integer exponent of a floating-point value.
+   Copyright (C) 1999-2025 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+static inline RET_TYPE
+IMPL_NAME (double x)
+{
+  uint64_t ux = asuint64 (x);
+  int ex = (ux & ~SIGN_MASK) >> MANTISSA_WIDTH;
+  if (__glibc_unlikely (ex == 0)) /* zero or subnormal */
+    {
+      /* Clear sign and exponent */
+      ux <<= 12;
+      if (ux == 0)
+	return RET_INVALID (RET_LOGB0);
+      /* subnormal  */
+      return (RET_TYPE)-1023 - stdc_leading_zeros (ux);
+    }
+  if (__glibc_unlikely (ex == EXPONENT_MASK >> MANTISSA_WIDTH))
+    /* NaN or Inf */
+    return RET_INVALID (ux << 12 ? RET_LOGBNAN : RET_LOGMAX);
+  return ex - 1023;
+}