initial import

5 files changed, 204 insertions, 0 deletions

diff --git a/sysdeps/m68k/fpu/switch/68881-sw.h b/sysdeps/m68k/fpu/switch/68881-sw.h
new file mode 100644
index 0000000000..3d7a3927f5
--- /dev/null
+++ b/sysdeps/m68k/fpu/switch/68881-sw.h
@@ -0,0 +1,64 @@
+/* Copyright (C) 1991, 1992 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 Library General Public License as
+published by the Free Software Foundation; either version 2 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
+Library General Public License for more details.
+
+You should have received a copy of the GNU Library General Public
+License along with the GNU C Library; see the file COPYING.LIB.  If
+not, write to the Free Software Foundation, Inc., 675 Mass Ave,
+Cambridge, MA 02139, USA.  */
+
+#ifndef	_68881_SWITCH_H
+
+#define	_68881_SWITCH_H	1
+#include <sys/cdefs.h>
+
+/* This is the format of the data at the code label for a function which
+   wants to switch depending on whether or not a 68881 is present.
+
+   Initially, `insn' is a `jsr' instruction, and `target' is __68881_switch.
+   The first time such a function is called, __68881_switch determines whether
+   or not a 68881 is present, and modifies the function accordingly.
+   Then `insn' is a `jmp' instruction, and `target' is the value of `fpu'
+   if there is 68881, or the value of `soft' if not.  */
+
+struct switch_caller
+  {
+    unsigned short int insn;	/* The `jsr' or `jmp' instruction.  */
+    __ptr_t target;		/* The target of the instruction.  */
+    __ptr_t soft;		/* The address of the soft function.  */
+    __ptr_t fpu;		/* The address of the 68881 function.  */
+  };
+
+/* These are opcodes (values for `insn', above) for `jmp' and `jsr'
+   instructions, respectively, to 32-bit absolute addresses.  */
+#define	JMP	0x4ef9
+#define	JSR	0x4eb9
+
+
+/* Function to determine whether or not a 68881 is available,
+   and modify its caller (which must be a `struct switch_caller', above,
+   in data space) to use the appropriate version.  */
+extern void EXFUN(__68881_switch, (int __dummy));
+
+
+/* Define FUNCTION as a `struct switch_caller' which will call
+   `__FUNCTION_68881' if a 68881 is present, and `__FUNCTION_soft' if not.
+#define	switching_function(FUNCTION) 					      \
+  struct switch_caller FUNCTION =					      \
+    {									      \
+      JSR, (__ptr_t) __68881_switch,					      \
+      __CONCAT(__CONCAT(__,FUNCTION),_soft),				      \
+      __CONCAT(__CONCAT(__,FUNCTION),_68881)				      \
+    }
+
+
+#endif	/* 68881-switch.h  */
diff --git a/sysdeps/m68k/fpu/switch/Dist b/sysdeps/m68k/fpu/switch/Dist
new file mode 100644
index 0000000000..1e00e4cd07
--- /dev/null
+++ b/sysdeps/m68k/fpu/switch/Dist
@@ -0,0 +1 @@
+68881-sw.h switch.c
diff --git a/sysdeps/m68k/fpu/switch/Makefile b/sysdeps/m68k/fpu/switch/Makefile
new file mode 100644
index 0000000000..fd8d7c11f4
--- /dev/null
+++ b/sysdeps/m68k/fpu/switch/Makefile
@@ -0,0 +1,52 @@
+# Copyright (C) 1991, 1992 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 Library General Public License as
+# published by the Free Software Foundation; either version 2 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
+# Library General Public License for more details.
+
+# You should have received a copy of the GNU Library General Public
+# License along with the GNU C Library; see the file COPYING.LIB.  If
+# not, write to the Free Software Foundation, Inc., 675 Mass Ave,
+# Cambridge, MA 02139, USA.
+
+ifeq ($(subdir),math)
+
+sysdep_routines := $(sysdep_routines) switch
+
+# Find all the sources that have 68881 versions.
++68881-sources := \
+  $(notdir $(wildcard $(addprefix $(filter %/fpu,$(sysdirs)),$(sources))))
+
+# Sysdep directories other than fpu and fpu/switch (this one).
++non68881-dirs := $(filter-out %/fpu %/fpu/switch,$(+sysdep_dirs))
+
+# Get a non-68881 version of the target.
++non68881-version = $(firstword $(wildcard $(addsuffix /$@,$(+non68881-dirs))))
+
+# Directory containing 68881 sources.
++68881-dir := $(filter %/fpu,$(+sysdep_dirs))
+
+# For all the files that have 68881 versions and don't exist already in
+# the source directory (math), automatically make ones that switch between
+# 68881 and soft versions.
+$(addprefix $(objpfx), \
+	    $(filter-out $(wildcard $(+68881-sources)),$(+68881-sources))):
+	(echo '#include <ansidecl.h>'		;\
+	 echo '#include <68881-sw.h>'		;\
+	 echo '#define $* __$*_68881'		;\
+	 echo '#include <$(+68881-dir)/$@>'	;\
+	 echo '#undef $*'			;\
+	 echo '#define $* __$*_soft'		;\
+	 echo '#include <$(non68881-version)>'	;\
+	 echo '#undef $*'			;\
+	 echo 'switching_function($*);') > $@-tmp
+	mv $@-tmp $@
+
+endif
diff --git a/sysdeps/m68k/fpu/switch/__math.h b/sysdeps/m68k/fpu/switch/__math.h
new file mode 100644
index 0000000000..c0f6966981
--- /dev/null
+++ b/sysdeps/m68k/fpu/switch/__math.h
@@ -0,0 +1 @@
+/* We don't want any inlines when we might not have a 68881.  */
diff --git a/sysdeps/m68k/fpu/switch/switch.c b/sysdeps/m68k/fpu/switch/switch.c
new file mode 100644
index 0000000000..057bd1509a
--- /dev/null
+++ b/sysdeps/m68k/fpu/switch/switch.c
@@ -0,0 +1,86 @@
+/* Copyright (C) 1991, 1992 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 Library General Public License as
+published by the Free Software Foundation; either version 2 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
+Library General Public License for more details.
+
+You should have received a copy of the GNU Library General Public
+License along with the GNU C Library; see the file COPYING.LIB.  If
+not, write to the Free Software Foundation, Inc., 675 Mass Ave,
+Cambridge, MA 02139, USA.  */
+
+#include <ansidecl.h>
+#include <signal.h>
+#include <68881-sw.h>
+
+
+/* The signal that is sent when a 68881 instruction
+   is executed and there is no 68881.  */
+#ifndef	TRAPSIG
+#define	TRAPSIG	SIGILL
+#endif
+
+/* Zero if no 68881, one if we have a 68881, or -1 if we don't know yet.  */
+static int have_fpu = -1;
+
+
+/* Signal handler for the trap that happens if we don't have a 68881.  */
+static void
+DEFUN(trap, (sig), int sig)
+{
+  have_fpu = 0;
+}
+
+/* This function is called by functions that want to switch.
+   The calling function must be a `struct switch_caller' in data space.
+   It determines whether a 68881 is present, and modifies its caller
+   to be a static jump to either the 68881 version or the soft version.
+   It then returns into the function it has chosen to do the work.  */
+void
+DEFUN(__68881_switch, (dummy), int dummy)
+{
+  PTR *return_address_location = &((PTR *) &dummy)[-1];
+  struct switch_caller *CONST caller
+    = (struct switch_caller *) (((short int *) *return_address_location) - 1);
+
+  if (have_fpu < 0)
+    {
+      /* Figure out whether or not we have a 68881.  */
+      __sighandler_t handler = signal (TRAPSIG, trap);
+      if (handler == SIG_ERR)
+	/* We can't figure it out, so assume we don't have a 68881.
+	   This assumption will never cause us any problems other than
+	   lost performance, while the reverse assumption could cause
+	   the program to crash.  */
+	have_fpu = 0;
+      else
+	{
+	  /* We set `have_fpu' to nonzero, and then execute a 68881
+	     no-op instruction.  If we have a 68881, this will do nothing.
+	     If we don't have one, this will trap and the signal handler
+	     will clear `have_fpu'.  */
+	  have_fpu = 1;
+	  asm ("fnop");
+
+	  /* Restore the old signal handler.  */
+	  (void) signal (TRAPSIG, handler);
+	}
+    }
+
+  /* Modify the caller to be a jump to the appropriate address.  */
+  caller->insn = JMP;
+  caller->target = have_fpu ? caller->fpu : caller->soft;
+
+  /* Make the address we will return to be the target we have chosen.
+     Our return will match the `jsr' done by the caller we have
+     just modified, and it will be just as if that had instead
+     been a `jmp' to the new target.  */
+  *return_address_location = caller->target;
+}