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65 lines
2.5 KiB
C
65 lines
2.5 KiB
C
/* Copyright (C) 1991, 1992 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If
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not, write to the Free Software Foundation, Inc., 675 Mass Ave,
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Cambridge, MA 02139, USA. */
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#ifndef _68881_SWITCH_H
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#define _68881_SWITCH_H 1
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#include <sys/cdefs.h>
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/* This is the format of the data at the code label for a function which
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wants to switch depending on whether or not a 68881 is present.
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Initially, `insn' is a `jsr' instruction, and `target' is __68881_switch.
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The first time such a function is called, __68881_switch determines whether
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or not a 68881 is present, and modifies the function accordingly.
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Then `insn' is a `jmp' instruction, and `target' is the value of `fpu'
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if there is 68881, or the value of `soft' if not. */
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struct switch_caller
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{
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unsigned short int insn; /* The `jsr' or `jmp' instruction. */
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__ptr_t target; /* The target of the instruction. */
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__ptr_t soft; /* The address of the soft function. */
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__ptr_t fpu; /* The address of the 68881 function. */
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};
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/* These are opcodes (values for `insn', above) for `jmp' and `jsr'
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instructions, respectively, to 32-bit absolute addresses. */
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#define JMP 0x4ef9
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#define JSR 0x4eb9
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/* Function to determine whether or not a 68881 is available,
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and modify its caller (which must be a `struct switch_caller', above,
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in data space) to use the appropriate version. */
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extern void EXFUN(__68881_switch, (int __dummy));
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/* Define FUNCTION as a `struct switch_caller' which will call
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`__FUNCTION_68881' if a 68881 is present, and `__FUNCTION_soft' if not.
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#define switching_function(FUNCTION) \
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struct switch_caller FUNCTION = \
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{ \
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JSR, (__ptr_t) __68881_switch, \
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__CONCAT(__CONCAT(__,FUNCTION),_soft), \
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__CONCAT(__CONCAT(__,FUNCTION),_68881) \
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}
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#endif /* 68881-switch.h */
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