fenv for arm

2 files changed, 355 insertions, 0 deletions

diff --git a/lib/libm/arch/arm/fenv.c b/lib/libm/arch/arm/fenv.c
new file mode 100644
index 00000000000..0230ca0ac53
--- /dev/null
+++ b/lib/libm/arch/arm/fenv.c
@@ -0,0 +1,269 @@
+/*	$OpenBSD: fenv.c,v 1.1 2011/04/24 00:20:27 martynas Exp $	*/
+
+/*
+ * Copyright (c) 2011 Martynas Venckus <martynas@openbsd.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/cdefs.h>
+#include <machine/ieeefp.h>
+
+#include <fenv.h>
+
+extern	fp_except	_softfloat_float_exception_flags;
+extern	fp_except	_softfloat_float_exception_mask;
+extern	fp_rnd		_softfloat_float_rounding_mode;
+extern	void		_softfloat_float_raise(fp_except);
+
+/*
+ * 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().
+ */
+fenv_t __fe_dfl_env = {
+	0,
+	0,
+	0
+};
+
+/*
+ * The feclearexcept() function clears the supported floating-point exceptions
+ * represented by `excepts'.
+ */
+int
+feclearexcept(int excepts)
+{
+	excepts &= FE_ALL_EXCEPT;
+
+	/* Clear the requested floating-point exceptions */
+	_softfloat_float_exception_flags &= ~excepts;
+
+	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)
+{
+	excepts &= FE_ALL_EXCEPT;
+
+	/* Store the results in flagp */
+	*flagp = _softfloat_float_exception_flags & excepts;
+
+	return (0);
+}
+
+/*
+ * The feraiseexcept() function raises the supported floating-point exceptions
+ * represented by the argument `excepts'.
+ */
+int
+feraiseexcept(int excepts)
+{
+	excepts &= FE_ALL_EXCEPT;
+
+	fesetexceptflag((fexcept_t *)&excepts, excepts);
+	_softfloat_float_raise(excepts);
+
+	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)
+{
+	excepts &= FE_ALL_EXCEPT;
+
+	/* Set the requested status flags */
+	_softfloat_float_exception_flags &= ~excepts;
+	_softfloat_float_exception_flags |= *flagp & excepts;
+
+	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)
+{
+	excepts &= FE_ALL_EXCEPT;
+
+	return (_softfloat_float_exception_flags & excepts);
+}
+
+/*
+ * The fegetround() function gets the current rounding direction.
+ */
+int
+fegetround(void)
+{
+	return (_softfloat_float_rounding_mode & _ROUND_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)
+{
+	/* Check whether requested rounding direction is supported */
+	if (round & ~_ROUND_MASK)
+		return (-1);
+
+	/*
+	 * Set the rounding direction
+	 */
+	_softfloat_float_rounding_mode &= ~_ROUND_MASK;
+	_softfloat_float_rounding_mode |= round;
+
+	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 floating-point sticky flags */
+	envp->__excepts = _softfloat_float_exception_flags;
+
+	/* Store the current floating-point masks */
+	envp->__mask = _softfloat_float_exception_mask;
+
+	/* Store the current floating-point control register */
+	envp->__round = _softfloat_float_rounding_mode;
+
+	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)
+{
+	/* Store the current floating-point environment */
+	fegetenv(envp);
+
+	/* Clear exception flags */
+	_softfloat_float_exception_flags &= ~FE_ALL_EXCEPT;
+
+	/* Mask all exceptions */
+	_softfloat_float_exception_mask &= ~FE_ALL_EXCEPT;
+
+	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)
+{
+	/* Load the floating-point sticky flags */
+	_softfloat_float_exception_flags = envp->__excepts & FE_ALL_EXCEPT;
+
+	/* Load the floating-point masks */
+	_softfloat_float_exception_mask = envp->__mask & FE_ALL_EXCEPT;
+
+	/* Load the floating-point rounding mode */
+	_softfloat_float_rounding_mode = envp->__round & _ROUND_MASK;
+
+	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)
+{
+	int excepts = _softfloat_float_exception_flags;
+
+	/* Install new floating-point environment */
+	fesetenv(envp);
+
+	/* Raise any previously accumulated exceptions */
+	feraiseexcept(excepts);
+
+	return (0);
+}
+
+/*
+ * The following functions are extentions to the standard
+ */
+int
+feenableexcept(int mask)
+{
+	int omask;
+
+	mask &= FE_ALL_EXCEPT;
+
+	omask = _softfloat_float_exception_mask & FE_ALL_EXCEPT;
+	_softfloat_float_exception_mask |= mask;
+
+	return (omask);
+
+}
+
+int
+fedisableexcept(int mask)
+{
+	unsigned int omask;
+
+	mask &= FE_ALL_EXCEPT;
+
+	omask = _softfloat_float_exception_mask & FE_ALL_EXCEPT;
+	_softfloat_float_exception_mask &= ~mask;
+
+	return (omask);
+}
+
+int
+fegetexcept(void)
+{
+	return (_softfloat_float_exception_mask & FE_ALL_EXCEPT);
+}
diff --git a/sys/arch/arm/include/fenv.h b/sys/arch/arm/include/fenv.h
new file mode 100644
index 00000000000..51a580a8230
--- /dev/null
+++ b/sys/arch/arm/include/fenv.h
@@ -0,0 +1,86 @@
+/*	$OpenBSD: fenv.h,v 1.1 2011/04/24 00:20:27 martynas Exp $	*/
+
+/*
+ * Copyright (c) 2011 Martynas Venckus <martynas@openbsd.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#ifndef	_ARM_FENV_H_
+#define	_ARM_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 registers.
+ */
+#define	FE_INVALID		0x01
+#define	FE_DIVBYZERO		0x02
+#define	FE_OVERFLOW		0x04
+#define	FE_UNDERFLOW		0x08
+#define	FE_INEXACT		0x10
+
+/*
+ * The following symbol is simply the bitwise-inclusive OR of all floating-point
+ * exception constants defined above.
+ */
+#define	FE_ALL_EXCEPT		\
+	(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW | FE_INEXACT)
+
+/*
+ * 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 registers.
+ */
+#define	FE_TONEAREST		0x0
+#define	FE_UPWARD		0x1
+#define	FE_DOWNWARD		0x2
+#define	FE_TOWARDZERO		0x3
+
+/*
+ * The following symbol is simply the bitwise-inclusive OR of all floating-point
+ * rounding direction constants defined above.
+ */
+#define	_ROUND_MASK		\
+	(FE_TOWARDZERO | FE_DOWNWARD | FE_TONEAREST | FE_UPWARD)
+
+/*
+ * fenv_t represents the entire floating-point environment
+ */
+typedef struct {
+	unsigned short __excepts;
+	unsigned short __mask;
+	unsigned short __round;
+} 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 short fexcept_t;
+
+#endif	/* ! _ARM_FENV_H_ */