Prepare for radical source tree reorganization. zack/build-layout-experiment

All top-level files and directories are moved into a temporary storage
directory, REORG.TODO, except for files that will certainly still
exist in their current form at top level when we're done (COPYING,
COPYING.LIB, LICENSES, NEWS, README), all old ChangeLog files (which
are moved to the new directory OldChangeLogs, instead), and the
generated file INSTALL (which is just deleted; in the new order, there
will be no generated files checked into version control).

1 files changed, 109 insertions, 0 deletions

diff --git a/REORG.TODO/sysdeps/x86/fpu_control.h b/REORG.TODO/sysdeps/x86/fpu_control.h
new file mode 100644
index 0000000000..7f8a57183a
--- /dev/null
+++ b/REORG.TODO/sysdeps/x86/fpu_control.h
@@ -0,0 +1,109 @@
+/* FPU control word bits.  x86 version.
+   Copyright (C) 1993-2017 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, see
+   <http://www.gnu.org/licenses/>.  */
+
+#ifndef _FPU_CONTROL_H
+#define _FPU_CONTROL_H	1
+
+/* Note that this file sets on x86-64 only the x87 FPU, it does not
+   touch the SSE unit.  */
+
+/* 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.  "*&" is used to
+   work around a bug in older versions of GCC.  __volatile__ is used
+   to support combination of writing the control register and reading
+   it back.  Without __volatile__, the old value may be used for reading
+   back under compiler optimization.
+
+   Note that the use of these macros is not sufficient anymore with
+   recent hardware nor on x86-64.  Some floating point operations are
+   executed in the SSE/SSE2 engines which have their own control and
+   status register.  */
+#define _FPU_GETCW(cw) __asm__ __volatile__ ("fnstcw %0" : "=m" (*&cw))
+#define _FPU_SETCW(cw) __asm__ __volatile__ ("fldcw %0" : : "m" (*&cw))
+
+/* Default control word set at startup.  */
+extern fpu_control_t __fpu_control;
+
+#endif	/* fpu_control.h */