summaryrefslogtreecommitdiff
path: root/libc/sysdeps/linux/alpha
diff options
context:
space:
mode:
Diffstat (limited to 'libc/sysdeps/linux/alpha')
-rw-r--r--libc/sysdeps/linux/alpha/bits/fenv.h123
1 files changed, 123 insertions, 0 deletions
diff --git a/libc/sysdeps/linux/alpha/bits/fenv.h b/libc/sysdeps/linux/alpha/bits/fenv.h
new file mode 100644
index 000000000..a9e89b498
--- /dev/null
+++ b/libc/sysdeps/linux/alpha/bits/fenv.h
@@ -0,0 +1,123 @@
+/* Copyright (C) 1997, 1998, 1999, 2000 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, write to the Free
+ Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ 02111-1307 USA. */
+
+#ifndef _FENV_H
+# error "Never use <bits/fenv.h> directly; include <fenv.h> instead."
+#endif
+
+
+/* Define the bits representing the exception.
+
+ Note that these are the bit positions as defined by the OSF/1
+ ieee_{get,set}_control_word interface and not by the hardware fpcr.
+
+ See the Alpha Architecture Handbook section 4.7.7.3 for details,
+ but in summary, trap shadows mean the hardware register can acquire
+ extra exception bits so for proper IEEE support the tracking has to
+ be done in software -- in this case with kernel support.
+
+ As to why the system call interface isn't in the same format as
+ the hardware register, only those crazy folks at DEC can tell you. */
+
+enum
+ {
+#ifdef __USE_GNU
+ FE_DENORMAL = 1UL << 22,
+#define FE_DENORMAL FE_DENORMAL
+#endif
+
+ FE_INEXACT = 1UL << 21,
+#define FE_INEXACT FE_INEXACT
+
+ FE_UNDERFLOW = 1UL << 20,
+#define FE_UNDERFLOW FE_UNDERFLOW
+
+ FE_OVERFLOW = 1UL << 19,
+#define FE_OVERFLOW FE_OVERFLOW
+
+ FE_DIVBYZERO = 1UL << 18,
+#define FE_DIVBYZERO FE_DIVBYZERO
+
+ FE_INVALID = 1UL << 17,
+#define FE_INVALID FE_INVALID
+
+ FE_ALL_EXCEPT = 0x3f << 17
+#define FE_ALL_EXCEPT FE_ALL_EXCEPT
+ };
+
+/* Alpha chips support all four defined rouding modes.
+
+ Note that code must be compiled to use dynamic rounding (/d) instructions
+ to see these changes. For gcc this is -mfp-rounding-mode=d; for DEC cc
+ this is -fprm d. The default for both is static rounding to nearest.
+
+ These are shifted down 58 bits from the hardware fpcr because the
+ functions are declared to take integers. */
+
+enum
+ {
+ FE_TOWARDZERO = 0,
+#define FE_TOWARDZERO FE_TOWARDZERO
+
+ FE_DOWNWARD = 1,
+#define FE_DOWNWARD FE_DOWNWARD
+
+ FE_TONEAREST = 2,
+#define FE_TONEAREST FE_TONEAREST
+
+ FE_UPWARD = 3,
+#define FE_UPWARD FE_UPWARD
+ };
+
+#ifdef __USE_GNU
+/* On later hardware, and later kernels for earlier hardware, we can forcibly
+ underflow denormal inputs and outputs. This can speed up certain programs
+ significantly, usually without affecting accuracy. */
+enum
+ {
+ FE_MAP_DMZ = 1UL << 12, /* Map denorm inputs to zero */
+#define FE_MAP_DMZ FE_MAP_DMZ
+
+ FE_MAP_UMZ = 1UL << 13, /* Map underflowed outputs to zero */
+#define FE_MAP_UMZ FE_MAP_UMZ
+ };
+#endif
+
+/* Type representing exception flags. */
+typedef unsigned long int fexcept_t;
+
+/* Type representing floating-point environment. */
+typedef unsigned long int fenv_t;
+
+/* If the default argument is used we use this value. Note that due to
+ architecture-specified page mappings, no user-space pointer will ever
+ have its two high bits set. Co-opt one. */
+#define FE_DFL_ENV ((__const fenv_t *) 0x8800000000000000UL)
+
+#ifdef __USE_GNU
+/* Floating-point environment where none of the exceptions are masked. */
+# define FE_NOMASK_ENV ((__const fenv_t *) 0x880000000000003eUL)
+
+/* Floating-point environment with (processor-dependent) non-IEEE floating
+ point. In this case, mapping denormals to zero. */
+# define FE_NONIEEE_ENV ((__const fenv_t *) 0x8800000000003000UL)
+#endif
+
+/* The system calls to talk to the kernel's FP code. */
+extern unsigned long int __ieee_get_fp_control (void) __THROW;
+extern void __ieee_set_fp_control (unsigned long int __value) __THROW;