1 files changed, 106 insertions, 0 deletions
diff --git a/libc/sysdeps/linux/alpha/fpu_control.h b/libc/sysdeps/linux/alpha/fpu_control.h
new file mode 100644
index 000000000..28acdf170
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+++ b/libc/sysdeps/linux/alpha/fpu_control.h
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+/* FPU control word bits.  Alpha-mapped-to-Intel version.
+   Copyright (C) 1996, 1998, 2000, 2002 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 _ALPHA_FPU_CONTROL_H
+#define _ALPHA_FPU_CONTROL_H
+
+/*
+ * Since many programs seem to hardcode the values passed to __setfpucw()
+ * (rather than using the manifest constants) we emulate the x87 interface
+ * here (at least where this makes sense).
+ *
+ *     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. I choose 0x1372.
+ */
+
+#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 -- without effect on Alpha */
+#define _FPU_EXTENDED 0x300   /* RECOMMENDED */
+#define _FPU_DOUBLE   0x200
+#define _FPU_SINGLE   0x0     /* DO NOT USE */
+
+/*
+ * rounding control---notice that on the Alpha this affects only
+ * instructions with the dynamic rounding mode qualifier (/d).
+ */
+#define _FPU_RC_NEAREST 0x000 /* RECOMMENDED */
+#define _FPU_RC_DOWN    0x400
+#define _FPU_RC_UP      0x800
+#define _FPU_RC_ZERO    0xC00
+
+#define _FPU_RESERVED 0xF0C0  /* Reserved bits in cw */
+
+
+/* Now two recommended cw */
+
+/* Linux default:
+     - extended precision
+     - rounding to positive infinity.  There is no /p instruction
+       qualifier.  By setting the dynamic rounding mode to +infinity,
+       one can use /d to get round to +infinity with no extra overhead
+       (so long as the default isn't changed, of course...)
+     - no exceptions enabled.  */
+
+#define _FPU_DEFAULT  0x137f
+
+/* IEEE:  same as above. */
+#define _FPU_IEEE     0x137f
+
+/* Type of the control word.  */
+typedef unsigned int fpu_control_t;
+
+/* Default control word set at startup.  */
+extern fpu_control_t __fpu_control;
+
+#endif	/* _ALPHA_FPU_CONTROL */