1 files changed, 98 insertions, 0 deletions
diff --git a/libc/sysdeps/linux/i386/fpu_control.h b/libc/sysdeps/linux/i386/fpu_control.h
new file mode 100644
index 000000000..ed9bf388a
--- /dev/null
+++ b/libc/sysdeps/linux/i386/fpu_control.h
@@ -0,0 +1,98 @@
+/* FPU control word bits.  i387 version.
+   Copyright (C) 1993,1995,1996,1997,1998,2000,2001 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Olaf Flebbe.
+
+   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, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#ifndef _FPU_CONTROL_H
+#define _FPU_CONTROL_H	1
+
+/* Here is the dirty part. Set up your 387 through the control word
+ * (cw) register.
+ *
+ *     15-13    12  11-10  9-8     7-6     5    4    3    2    1    0
+ * | reserved | IC | RC  | PC | reserved | PM | UM | OM | ZM | DM | IM
+ *
+ * IM: Invalid operation mask
+ * DM: Denormalized operand mask
+ * ZM: Zero-divide mask
+ * OM: Overflow mask
+ * UM: Underflow mask
+ * PM: Precision (inexact result) mask
+ *
+ * Mask bit is 1 means no interrupt.
+ *
+ * PC: Precision control
+ * 11 - round to extended precision
+ * 10 - round to double precision
+ * 00 - round to single precision
+ *
+ * RC: Rounding control
+ * 00 - rounding to nearest
+ * 01 - rounding down (toward - infinity)
+ * 10 - rounding up (toward + infinity)
+ * 11 - rounding toward zero
+ *
+ * IC: Infinity control
+ * That is for 8087 and 80287 only.
+ *
+ * The hardware default is 0x037f which we use.
+ */
+
+#include <features.h>
+
+/* masking of interrupts */
+#define _FPU_MASK_IM  0x01
+#define _FPU_MASK_DM  0x02
+#define _FPU_MASK_ZM  0x04
+#define _FPU_MASK_OM  0x08
+#define _FPU_MASK_UM  0x10
+#define _FPU_MASK_PM  0x20
+
+/* precision control */
+#define _FPU_EXTENDED 0x300	/* libm requires double extended precision.  */
+#define _FPU_DOUBLE   0x200
+#define _FPU_SINGLE   0x0
+
+/* rounding control */
+#define _FPU_RC_NEAREST 0x0    /* RECOMMENDED */
+#define _FPU_RC_DOWN    0x400
+#define _FPU_RC_UP      0x800
+#define _FPU_RC_ZERO    0xC00
+
+#define _FPU_RESERVED 0xF0C0  /* Reserved bits in cw */
+
+
+/* The fdlibm code requires strict IEEE double precision arithmetic,
+   and no interrupts for exceptions, rounding to nearest.  */
+
+#define _FPU_DEFAULT  0x037f
+
+/* IEEE:  same as above.  */
+#define _FPU_IEEE     0x037f
+
+/* Type of the control word.  */
+typedef unsigned int fpu_control_t __attribute__ ((__mode__ (__HI__)));
+
+/* Macros for accessing the hardware control word.  */
+#define _FPU_GETCW(cw) __asm__ ("fnstcw %0" : "=m" (*&cw))
+#define _FPU_SETCW(cw) __asm__ ("fldcw %0" : : "m" (*&cw))
+
+/* Default control word set at startup.  */
+extern fpu_control_t __fpu_control;
+
+#endif	/* fpu_control.h */