On 3/22/11, Mark Kettenis <[email protected]> wrote:
>> Date: Sun, 20 Mar 2011 03:08:41 +0200
>> From: Martynas Venckus <[email protected]>
>>
>> Index: include/fenv.h
>> ===================================================================
>> RCS file: include/fenv.h
>> diff -N include/fenv.h
>> --- /dev/null 1 Jan 1970 00:00:00 -0000
>> +++ include/fenv.h 18 Mar 2011 20:38:10 -0000
>> @@ -0,0 +1,59 @@
>> +/* $OpenBSD$ */
>> +/* $NetBSD: fenv.h,v 1.2.4.1 2011/02/08 16:18:55 bouyer Exp $ */
>> +
>> +/*
>> + * Copyright (c) 2010 The NetBSD Foundation, Inc.
>> + * 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
>> + */
>> +
>> +#ifndef _FENV_H_
>> +#define _FENV_H_
>> +
>> +#include <sys/cdefs.h>
>> +#include <machine/fenv.h>
>> +
>> +__BEGIN_DECLS
>> +
>> +int feclearexcept(int);
>> +int fegetexceptflag(fexcept_t *, int);
>> +int feraiseexcept(int);
>> +int fesetexceptflag(const fexcept_t *, int);
>> +int fetestexcept(int);
>> +
>> +int fegetround(void);
>> +int fesetround(int);
>> +int fegetenv(fenv_t *);
>> +int feholdexcept(fenv_t *);
>> +int fesetenv(const fenv_t *);
>> +int feupdateenv(const fenv_t *);
>> +
>> +#if __BSD_VISIBLE || defined(_GNU_SOURCE)
>> +int feenableexcept(int mask);
>> +int fedisableexcept(int mask);
>> +int fegetexcept(void);
>> +#endif /* __BSD_VISIBLE || defined(_GNU_SOURCE) */
>
> I think we should leave off the || defined(_GNU_SOURCE) bit here.
> Nowhere else in our system headers do we care about GNU extensions.
> And if we would care about them, we probably should introduce
> __GNU_VISIBLE and set it appropriately in <sys/cdefs.h> based on
> whether _GNU_SOURCE is defined or not. But since _GNU_SOURCE seems to
> imply BSD extensions on Linux, I think just checking __BSD_VISIBLE is
> the right thing to do.
I agree with Mark here. Also, I took a second look, and found couple more bugs:
- Fedisableexcept didn't clear non-FE_ALL_EXCEPT bits for mask, making
it possible to corrupt control/mxcsr.
- Values returned by feenableexcept and fedisableexcept weren't quite
right. They did ~(control&FE_ALL_EXCEPT) instead of
(~control)&FE_ALL_EXCEPT, setting all non-FE_ALL_EXCEPT, breaking apps
testing for equality.
Hopefully, this is the final version for amd64. (-;
Index: include/Makefile
===================================================================
RCS file: /cvs/src/include/Makefile,v
retrieving revision 1.157
diff -u -r1.157 Makefile
--- include/Makefile 28 Oct 2010 08:34:37 -0000 1.157
+++ include/Makefile 18 Mar 2011 17:20:42 -0000
@@ -12,8 +12,8 @@
# Missing: mp.h
FILES= a.out.h ar.h assert.h bitstring.h blf.h bm.h bsd_auth.h \
complex.h cpio.h ctype.h curses.h db.h dbm.h des.h dirent.h disktab.h \
- dlfcn.h elf_abi.h err.h errno.h fnmatch.h fstab.h fts.h ftw.h getopt.h \
- glob.h grp.h ifaddrs.h inttypes.h iso646.h kvm.h langinfo.h \
+ dlfcn.h elf_abi.h err.h errno.h fenv.h fnmatch.h fstab.h fts.h ftw.h \
+ getopt.h glob.h grp.h ifaddrs.h inttypes.h iso646.h kvm.h langinfo.h \
libgen.h limits.h locale.h login_cap.h malloc.h math.h md4.h \
md5.h memory.h mpool.h ndbm.h netdb.h netgroup.h nlist.h nl_types.h \
ohash.h paths.h poll.h pwd.h ranlib.h re_comp.h \
Index: include/fenv.h
===================================================================
RCS file: include/fenv.h
diff -N include/fenv.h
--- /dev/null 1 Jan 1970 00:00:00 -0000
+++ include/fenv.h 18 Mar 2011 20:38:10 -0000
@@ -0,0 +1,59 @@
+/* $OpenBSD$ */
+/* $NetBSD: fenv.h,v 1.2.4.1 2011/02/08 16:18:55 bouyer Exp $ */
+
+/*
+ * Copyright (c) 2010 The NetBSD Foundation, Inc.
+ * 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
+ */
+
+#ifndef _FENV_H_
+#define _FENV_H_
+
+#include <sys/cdefs.h>
+#include <machine/fenv.h>
+
+__BEGIN_DECLS
+
+int feclearexcept(int);
+int fegetexceptflag(fexcept_t *, int);
+int feraiseexcept(int);
+int fesetexceptflag(const fexcept_t *, int);
+int fetestexcept(int);
+
+int fegetround(void);
+int fesetround(int);
+int fegetenv(fenv_t *);
+int feholdexcept(fenv_t *);
+int fesetenv(const fenv_t *);
+int feupdateenv(const fenv_t *);
+
+#if __BSD_VISIBLE
+int feenableexcept(int mask);
+int fedisableexcept(int mask);
+int fegetexcept(void);
+#endif /* __BSD_VISIBLE */
+
+__END_DECLS
+
+#endif /* ! _FENV_H_ */
Index: sys/arch/amd64/include/fenv.h
===================================================================
RCS file: sys/arch/amd64/include/fenv.h
diff -N sys/arch/amd64/include/fenv.h
--- /dev/null 1 Jan 1970 00:00:00 -0000
+++ sys/arch/amd64/include/fenv.h 18 Mar 2011 20:37:58 -0000
@@ -0,0 +1,105 @@
+/* $OpenBSD$ */
+/* $NetBSD: fenv.h,v 1.1 2010/07/31 21:47:54 joerg Exp $ */
+
+/*-
+ * Copyright (c) 2004-2005 David Schultz <das (at) 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.
+ */
+
+#ifndef _AMD64_FENV_H_
+#define _AMD64_FENV_H_
+
+/*
+ * Each symbol representing a floating point exception expands to an integer
+ * constant expression with values, such that bitwise-inclusive ORs of _all
+ * combinations_ of the constants result in distinct values.
+ *
+ * We use such values that allow direct bitwise operations on FPU/SSE
registers.
+ */
+#define FE_INVALID 0x01
+#define FE_DENORMAL 0x02
+#define FE_DIVBYZERO 0x04
+#define FE_OVERFLOW 0x08
+#define FE_UNDERFLOW 0x10
+#define FE_INEXACT 0x20
+
+/*
+ * The following symbol is simply the bitwise-inclusive OR of all
floating-point
+ * exception constants defined above.
+ */
+#define FE_ALL_EXCEPT \
+ (FE_DIVBYZERO | FE_INEXACT | FE_INVALID | FE_OVERFLOW | FE_UNDERFLOW)
+
+/*
+ * Each symbol representing the rounding direction, expands to an integer
+ * constant expression whose value is distinct non-negative value.
+ *
+ * We use such values that allow direct bitwise operations on FPU/SSE
registers.
+ */
+#define FE_TONEAREST 0x000
+#define FE_DOWNWARD 0x400
+#define FE_UPWARD 0x800
+#define FE_TOWARDZERO 0xC00
+
+/*
+ * As compared to the x87 control word, the SSE unit's control word
+ * has the rounding control bits offset by 3 and the exception mask
+ * bits offset by 7.
+ */
+#define _X87_ROUNDING_MASK 0xC00
+#define _SSE_ROUNDING_MASK (0xC00 << 3)
+#define _SSE_ROUND_SHIFT 3
+#define _SSE_EMASK_SHIFT 7
+
+/*
+ * fenv_t represents the entire floating-point environment
+ */
+typedef struct {
+ struct {
+ unsigned int __control; /* Control word register */
+ unsigned int __status; /* Status word register */
+ unsigned int __tag; /* Tag word register */
+ unsigned int __others[4]; /* EIP, Pointer Selector, etc */
+ } x87;
+ unsigned int __mxcsr; /* Control, status register */
+} fenv_t;
+
+extern fenv_t __fe_dfl_env;
+#define FE_DFL_ENV ((const fenv_t *) &__fe_dfl_env)
+
+/*
+ * fexcept_t represents the floating-point status flags collectively, including
+ * any status the implementation associates with the flags.
+ *
+ * A floating-point status flag is a system variable whose value is set (but
+ * never cleared) when a floating-point exception is raised, which occurs as a
+ * side effect of exceptional floating-point arithmetic to provide auxiliary
+ * information.
+ *
+ * A floating-point control mode is a system variable whose value may be set by
+ * the user to affect the subsequent behavior of floating-point arithmetic.
+ */
+typedef unsigned int fexcept_t;
+
+#endif /* ! _AMD64_FENV_H_ */
Index: lib/libm/Makefile
===================================================================
RCS file: /cvs/src/lib/libm/Makefile,v
retrieving revision 1.76
diff -u -r1.76 Makefile
--- lib/libm/Makefile 19 Jul 2010 12:48:23 -0000 1.76
+++ lib/libm/Makefile 20 Mar 2011 00:43:57 -0000
@@ -82,6 +82,7 @@
e_rem_pio2.c \
e_rem_pio2f.c e_remainder.c e_remainderf.c e_scalb.c e_scalbf.c \
e_sinh.c e_sinhf.c e_sqrt.c e_sqrtf.c \
+ fenv.c \
k_cos.c k_cosf.c k_rem_pio2.c k_rem_pio2f.c k_sin.c k_sinf.c \
k_tan.c k_tanf.c \
s_lround.c s_lroundf.c s_llround.c s_llroundf.c \
Index: lib/libm/shlib_version
===================================================================
RCS file: /cvs/src/lib/libm/shlib_version,v
retrieving revision 1.12
diff -u -r1.12 shlib_version
@@ -1,2 +1,2 @@
major=5
-minor=2
+minor=3
Index: lib/libm/arch/amd64/fenv.c
===================================================================
RCS file: lib/libm/arch/amd64/fenv.c
diff -N lib/libm/arch/amd64/fenv.c
--- /dev/null 1 Jan 1970 00:00:00 -0000
+++ lib/libm/arch/amd64/fenv.c 16 Apr 2011 21:20:47 -0000
@@ -0,0 +1,453 @@
+/* $OpenBSD$ */
+/* $NetBSD: fenv.c,v 1.1 2010/07/31 21:47:53 joerg Exp $ */
+
+/*-
+ * Copyright (c) 2004-2005 David Schultz <das (at) 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.
+ */
+
+#include <sys/cdefs.h>
+#include <machine/fpu.h>
+
+#include <fenv.h>
+#include <string.h>
+
+/*
+ * The following constant represents the default floating-point environment
+ * (that is, the one installed at program startup) and has type pointer to
+ * const-qualified fenv_t.
+ *
+ * It can be used as an argument to the functions within the <fenv.h> header
+ * that manage the floating-point environment, namely fesetenv() and
+ * feupdateenv().
+ *
+ * x87 fpu registers are 16bit wide. The upper bits, 31-16, are marked as
+ * RESERVED. We provide a partial floating-point environment, where we
+ * define only the lower bits. The reserved bits are extracted and set by
+ * the consumers of FE_DFL_ENV, during runtime.
+ */
+fenv_t __fe_dfl_env = {
+ {
+ 0xffff0000 | __INITIAL_NPXCW__, /* Control word register */
+ 0xffff0000, /* Status word register */
+ 0xffffffff, /* Tag word register */
+ {
+ 0x00000000,
+ 0x00000000,
+ 0x00000000,
+ 0xffff0000,
+ },
+ },
+ __INITIAL_MXCSR__ /* MXCSR register */
+};
+
+
+/*
+ * The feclearexcept() function clears the supported floating-point exceptions
+ * represented by `excepts'.
+ */
+int
+feclearexcept(int excepts)
+{
+ fenv_t fenv;
+ unsigned int mxcsr;
+
+ excepts &= FE_ALL_EXCEPT;
+
+ /* Store the current x87 floating-point environment */
+ __asm__ __volatile__ ("fnstenv %0" : "=m" (*&fenv));
+
+ /* Clear the requested floating-point exceptions */
+ fenv.x87.__status &= ~excepts;
+
+ /* Load the x87 floating-point environent */
+ __asm__ __volatile__ ("fldenv %0" : : "m" (fenv));
+
+ /* Same for SSE environment */
+ __asm__ __volatile__ ("stmxcsr %0" : "=m" (*&mxcsr));
+ mxcsr &= ~excepts;
+ __asm__ __volatile__ ("ldmxcsr %0" : : "m" (mxcsr));
+
+ return (0);
+}
+
+/*
+ * The fegetexceptflag() function stores an implementation-defined
+ * representation of the states of the floating-point status flags indicated by
+ * the argument excepts in the object pointed to by the argument flagp.
+ */
+int
+fegetexceptflag(fexcept_t *flagp, int excepts)
+{
+ unsigned short x87_status;
+ unsigned int mxcsr;
+
+ excepts &= FE_ALL_EXCEPT;
+
+ /* Store the current x87 status register */
+ __asm__ __volatile__ ("fnstsw %0" : "=am" (*&x87_status));
+
+ /* Store the MXCSR register */
+ __asm__ __volatile__ ("stmxcsr %0" : "=m" (*&mxcsr));
+
+ /* Store the results in flagp */
+ *flagp = (x87_status | mxcsr) & excepts;
+
+ return (0);
+}
+
+/*
+ * The feraiseexcept() function raises the supported floating-point exceptions
+ * represented by the argument `excepts'.
+ *
+ * The standard explicitly allows us to execute an instruction that has the
+ * exception as a side effect, but we choose to manipulate the status register
+ * directly.
+ *
+ * The validation of input is being deferred to fesetexceptflag().
+ */
+int
+feraiseexcept(int excepts)
+{
+ excepts &= FE_ALL_EXCEPT;
+
+ fesetexceptflag((fexcept_t *)&excepts, excepts);
+ __asm__ __volatile__ ("fwait");
+
+ return (0);
+}
+
+/*
+ * This function sets the floating-point status flags indicated by the argument
+ * `excepts' to the states stored in the object pointed to by `flagp'. It does
+ * NOT raise any floating-point exceptions, but only sets the state
of the flags.
+ */
+int
+fesetexceptflag(const fexcept_t *flagp, int excepts)
+{
+ fenv_t fenv;
+ unsigned int mxcsr;
+
+ excepts &= FE_ALL_EXCEPT;
+
+ /* Store the current x87 floating-point environment */
+ __asm__ __volatile__ ("fnstenv %0" : "=m" (*&fenv));
+
+ /* Set the requested status flags */
+ fenv.x87.__status &= ~excepts;
+ fenv.x87.__status |= *flagp & excepts;
+
+ /* Load the x87 floating-point environent */
+ __asm__ __volatile__ ("fldenv %0" : : "m" (fenv));
+
+ /* Same for SSE environment */
+ __asm__ __volatile__ ("stmxcsr %0" : "=m" (*&mxcsr));
+ mxcsr &= ~excepts;
+ mxcsr |= *flagp & excepts;
+ __asm__ __volatile__ ("ldmxcsr %0" : : "m" (mxcsr));
+
+ return (0);
+}
+
+/*
+ * The fetestexcept() function determines which of a specified subset of the
+ * floating-point exception flags are currently set. The `excepts' argument
+ * specifies the floating-point status flags to be queried.
+ */
+int
+fetestexcept(int excepts)
+{
+ unsigned short x87_status;
+ unsigned int mxcsr;
+
+ excepts &= FE_ALL_EXCEPT;
+
+ /* Store the current x87 status register */
+ __asm__ __volatile__ ("fnstsw %0" : "=am" (*&x87_status));
+
+ /* Store the MXCSR register state */
+ __asm__ __volatile__ ("stmxcsr %0" : "=m" (*&mxcsr));
+
+ return ((x87_status | mxcsr) & excepts);
+}
+
+/*
+ * The fegetround() function gets the current rounding direction.
+ */
+int
+fegetround(void)
+{
+ unsigned short control;
+ unsigned int mxcsr;
+
+ /*
+ * We check both the x87 floating-point unit _and_ the SSE unit.
+ * Normally, those two must agree with respect to each other. If they
+ * don't, it's not our fault and the result is non-determinable, in
+ * which case POSIX says that a negative value should be returned.
+ */
+ __asm__ __volatile__ ("fnstcw %0" : "=m" (*&control));
+ __asm__ __volatile__ ("stmxcsr %0" : "=m" (*&mxcsr));
+
+ if ((control & _X87_ROUNDING_MASK)
+ != ((mxcsr & _SSE_ROUNDING_MASK) >> 3)) {
+ return (-1);
+ }
+
+ return (control & _X87_ROUNDING_MASK);
+}
+
+/*
+ * The fesetround() function establishes the rounding direction represented by
+ * its argument `round'. If the argument is not equal to the value of
a rounding
+ * direction macro, the rounding direction is not changed.
+ */
+int
+fesetround(int round)
+{
+ unsigned short control;
+ unsigned int mxcsr;
+
+ /* Check whether requested rounding direction is supported */
+ if (round & ~_X87_ROUNDING_MASK)
+ return (-1);
+
+ /* Store the current x87 control word register */
+ __asm__ __volatile__ ("fnstcw %0" : "=m" (*&control));
+
+ /*
+ * Set the rounding direction
+ * Rounding Control is bits 10-11, so shift appropriately
+ */
+ control &= ~_X87_ROUNDING_MASK;
+ control |= round;
+
+ /* Load the x87 control word register */
+ __asm__ __volatile__ ("fldcw %0" : : "m" (control));
+
+ /*
+ * Same for the SSE environment
+ * Rounding Control is bits 13-14, so shift appropriately
+ */
+ __asm__ __volatile__ ("stmxcsr %0" : "=m" (*&mxcsr));
+ mxcsr &= ~_SSE_ROUNDING_MASK;
+ mxcsr |= (round << _SSE_ROUND_SHIFT);
+ __asm__ __volatile__ ("ldmxcsr %0" : : "m" (mxcsr));
+
+ return (0);
+}
+
+/*
+ * The fegetenv() function attempts to store the current floating-point
+ * environment in the object pointed to by envp.
+ */
+int
+fegetenv(fenv_t *envp)
+{
+ /* Store the current x87 floating-point environment */
+ __asm__ __volatile__ ("fnstenv %0" : "=m" (*envp));
+
+ /* Store the MXCSR register state */
+ __asm__ __volatile__ ("stmxcsr %0" : "=m" (envp->__mxcsr));
+
+ /*
+ * When an FNSTENV instruction is executed, all pending exceptions are
+ * essentially lost (either the x87 FPU status register is cleared or all
+ * exceptions are masked).
+ *
+ * 8.6 X87 FPU EXCEPTION SYNCHRONIZATION -
+ * Intel(R) 64 and IA-32 Architectures Softare Developer's Manual - Vol 1
+ */
+ __asm__ __volatile__ ("fldcw %0" : : "m" (envp->x87.__control));
+
+ return (0);
+}
+
+/*
+ * The feholdexcept() function saves the current floating-point environment
+ * in the object pointed to by envp, clears the floating-point status
flags, and
+ * then installs a non-stop (continue on floating-point exceptions) mode, if
+ * available, for all floating-point exceptions.
+ */
+int
+feholdexcept(fenv_t *envp)
+{
+ unsigned int mxcsr;
+
+ /* Store the current x87 floating-point environment */
+ __asm__ __volatile__ ("fnstenv %0" : "=m" (*envp));
+
+ /* Clear all exception flags in FPU */
+ __asm__ __volatile__ ("fnclex");
+
+ /* Store the MXCSR register state */
+ __asm__ __volatile__ ("stmxcsr %0" : "=m" (envp->__mxcsr));
+
+ /* Clear exception flags in MXCSR XXX */
+ mxcsr = envp->__mxcsr;
+ mxcsr &= ~FE_ALL_EXCEPT;
+
+ /* Mask all exceptions */
+ mxcsr |= FE_ALL_EXCEPT << _SSE_EMASK_SHIFT;
+
+ __asm__ __volatile__ ("ldmxcsr %0" : : "m" (mxcsr));
+
+ return (0);
+}
+
+/*
+ * The fesetenv() function attempts to establish the floating-point environment
+ * represented by the object pointed to by envp. The argument `envp' points
+ * to an object set by a call to fegetenv() or feholdexcept(), or equal a
+ * floating-point environment macro. The fesetenv() function does not raise
+ * floating-point exceptions, but only installs the state of the floating-point
+ * status flags represented through its argument.
+ */
+int
+fesetenv(const fenv_t *envp)
+{
+ fenv_t fenv;
+
+ /* Store the x87 floating-point environment */
+ memset(&fenv, 0, sizeof fenv);
+ __asm__ __volatile__ ("fnstenv %0" : "=m" (*&fenv));
+
+ __fe_dfl_env.x87.__control = (fenv.x87.__control & 0xffff0000)
+ | (__fe_dfl_env.x87.__control & 0x0000ffff);
+ __fe_dfl_env.x87.__status = (fenv.x87.__status & 0xffff0000)
+ | (__fe_dfl_env.x87.__status & 0x0000ffff);
+ __fe_dfl_env.x87.__tag = (fenv.x87.__tag & 0xffff0000)
+ | (__fe_dfl_env.x87.__tag & 0x0000ffff);
+ __fe_dfl_env.x87.__others[3] = (fenv.x87.__others[3] & 0xffff0000)
+ | (__fe_dfl_env.x87.__others[3] & 0x0000ffff);
+ __asm__ __volatile__ ("fldenv %0" : : "m" (*envp));
+
+ /* Store the MXCSR register */
+ __asm__ __volatile__ ("ldmxcsr %0" : : "m" (envp->__mxcsr));
+
+ return (0);
+}
+
+/*
+ * The feupdateenv() function saves the currently raised floating-point
+ * exceptions in its automatic storage, installs the floating-point environment
+ * represented by the object pointed to by `envp', and then raises the saved
+ * floating-point exceptions. The argument `envp' shall point to an object set
+ * by a call to feholdexcept() or fegetenv(), or equal a floating-point
+ * environment macro.
+ */
+int
+feupdateenv(const fenv_t *envp)
+{
+ fenv_t fenv;
+ unsigned short x87_status;
+ unsigned int mxcsr;
+
+ /* Store the x87 floating-point environment */
+ memset(&fenv, 0, sizeof(fenv));
+ __asm__ __volatile__ ("fnstenv %0" : "=m" (*&fenv));
+
+ __fe_dfl_env.x87.__control = (fenv.x87.__control & 0xffff0000)
+ | (__fe_dfl_env.x87.__control & 0x0000ffff);
+ __fe_dfl_env.x87.__status = (fenv.x87.__status & 0xffff0000)
+ | (__fe_dfl_env.x87.__status & 0x0000ffff);
+ __fe_dfl_env.x87.__tag = (fenv.x87.__tag & 0xffff0000)
+ | (__fe_dfl_env.x87.__tag & 0x0000ffff);
+ __fe_dfl_env.x87.__others[3] = (fenv.x87.__others[3] & 0xffff0000)
+ | (__fe_dfl_env.x87.__others[3] & 0x0000ffff);
+
+ /* Store the x87 status register */
+ __asm__ __volatile__ ("fnstsw %0" : "=am" (*&x87_status));
+
+ /* Store the MXCSR register */
+ __asm__ __volatile__ ("stmxcsr %0" : "=m" (*&mxcsr));
+
+ /* Install new floating-point environment */
+ fesetenv(envp);
+
+ /* Raise any previously accumulated exceptions */
+ feraiseexcept(x87_status | mxcsr);
+
+ return (0);
+}
+
+/*
+ * The following functions are extentions to the standard
+ */
+int
+feenableexcept(int mask)
+{
+ unsigned int mxcsr, omask;
+ unsigned short control;
+
+ mask &= FE_ALL_EXCEPT;
+
+ __asm__ __volatile__ ("fnstcw %0" : "=m" (*&control));
+ __asm__ __volatile__ ("stmxcsr %0" : "=m" (*&mxcsr));
+
+ omask = ~(control | (mxcsr >> _SSE_EMASK_SHIFT)) & FE_ALL_EXCEPT;
+ control &= ~mask;
+ __asm__ __volatile__ ("fldcw %0" : : "m" (control));
+
+ mxcsr &= ~(mask << _SSE_EMASK_SHIFT);
+ __asm__ __volatile__ ("ldmxcsr %0" : : "m" (mxcsr));
+
+ return (omask);
+
+}
+
+int
+fedisableexcept(int mask)
+{
+ unsigned int mxcsr, omask;
+ unsigned short control;
+
+ mask &= FE_ALL_EXCEPT;
+
+ __asm__ __volatile__ ("fnstcw %0" : "=m" (*&control));
+ __asm__ __volatile__ ("stmxcsr %0" : "=m" (*&mxcsr));
+
+ omask = ~(control | (mxcsr >> _SSE_EMASK_SHIFT)) & FE_ALL_EXCEPT;
+ control |= mask;
+ __asm__ __volatile__ ("fldcw %0" : : "m" (control));
+
+ mxcsr |= mask << _SSE_EMASK_SHIFT;
+ __asm__ __volatile__ ("ldmxcsr %0" : : "m" (mxcsr));
+
+ return (omask);
+}
+
+int
+fegetexcept(void)
+{
+ unsigned short control;
+
+ /*
+ * We assume that the masks for the x87 and the SSE unit are
+ * the same.
+ */
+ __asm__ __volatile__ ("fnstcw %0" : "=m" (*&control));
+
+ return (~control & FE_ALL_EXCEPT);
+}
