diff --git a/libc/include/bits/fenv_x86.h b/libc/include/bits/fenv_x86.h
new file mode 100644
index 0000000..75b109b
--- /dev/null
+++ b/libc/include/bits/fenv_x86.h
@@ -0,0 +1,69 @@
+/*-
+ * Copyright (c) 2004-2005 David Schultz <das@FreeBSD.ORG>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD: src/lib/msun/i387/fenv.h,v 1.4 2005/03/17 22:21:46 das Exp $
+ */
+
+#ifndef _BITS_FENV_X86_H_
+#define _BITS_FENV_X86_H_
+
+#include <sys/types.h>
+
+__BEGIN_DECLS
+
+/*
+ * To preserve binary compatibility with FreeBSD 5.3, we pack the
+ * mxcsr into some reserved fields, rather than changing sizeof(fenv_t).
+ */
+typedef struct {
+  __uint16_t __control;
+  __uint16_t __mxcsr_hi;
+  __uint16_t __status;
+  __uint16_t __mxcsr_lo;
+  __uint32_t __tag;
+  char       __other[16];
+} fenv_t;
+
+typedef __uint16_t fexcept_t;
+
+/* Exception flags */
+#define FE_INVALID    0x01
+#define FE_DENORMAL   0x02
+#define FE_DIVBYZERO  0x04
+#define FE_OVERFLOW   0x08
+#define FE_UNDERFLOW  0x10
+#define FE_INEXACT    0x20
+#define FE_ALL_EXCEPT (FE_DIVBYZERO | FE_DENORMAL | FE_INEXACT | \
+                       FE_INVALID | FE_OVERFLOW | FE_UNDERFLOW)
+
+/* Rounding modes */
+#define FE_TONEAREST  0x0000
+#define FE_DOWNWARD   0x0400
+#define FE_UPWARD     0x0800
+#define FE_TOWARDZERO 0x0c00
+
+__END_DECLS
+
+#endif