diff options
Diffstat (limited to 'sysdeps/m68k/m680x0/fpu/switch')
| -rw-r--r-- | sysdeps/m68k/m680x0/fpu/switch/68881-sw.h | 64 | ||||
| -rw-r--r-- | sysdeps/m68k/m680x0/fpu/switch/Makefile | 51 | ||||
| -rw-r--r-- | sysdeps/m68k/m680x0/fpu/switch/bits/mathinline.h | 1 | ||||
| -rw-r--r-- | sysdeps/m68k/m680x0/fpu/switch/switch.c | 87 |
4 files changed, 203 insertions, 0 deletions
diff --git a/sysdeps/m68k/m680x0/fpu/switch/68881-sw.h b/sysdeps/m68k/m680x0/fpu/switch/68881-sw.h new file mode 100644 index 0000000000..c5a0f71fa6 --- /dev/null +++ b/sysdeps/m68k/m680x0/fpu/switch/68881-sw.h @@ -0,0 +1,64 @@ +/* Copyright (C) 1991, 1992, 1997, 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 _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. */ + void *target; /* The target of the instruction. */ + void *soft; /* The address of the soft function. */ + void *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 __68881_switch (int __dummy) __THROW; + + +/* 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/m680x0/fpu/switch/Makefile b/sysdeps/m68k/m680x0/fpu/switch/Makefile new file mode 100644 index 0000000000..c04107163c --- /dev/null +++ b/sysdeps/m68k/m680x0/fpu/switch/Makefile @@ -0,0 +1,51 @@ +# Copyright (C) 1991, 1992, 1997 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. + +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 <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/m680x0/fpu/switch/bits/mathinline.h b/sysdeps/m68k/m680x0/fpu/switch/bits/mathinline.h new file mode 100644 index 0000000000..c0f6966981 --- /dev/null +++ b/sysdeps/m68k/m680x0/fpu/switch/bits/mathinline.h @@ -0,0 +1 @@ +/* We don't want any inlines when we might not have a 68881. */ diff --git a/sysdeps/m68k/m680x0/fpu/switch/switch.c b/sysdeps/m68k/m680x0/fpu/switch/switch.c new file mode 100644 index 0000000000..e0558176dc --- /dev/null +++ b/sysdeps/m68k/m680x0/fpu/switch/switch.c @@ -0,0 +1,87 @@ +/* Copyright (C) 1991, 1992, 1997 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. */ + +#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 +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 +__68881_switch (dummy) + int dummy; +{ + void **return_address_location = &((void **) &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; +} |