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Formerly ./m68k/fpu/switch/switch.c.~5~

This commit is contained in:
Roland McGrath 1992-03-11 23:27:38 +00:00
parent e96f4881db
commit f4a378895f
1 changed files with 7 additions and 13 deletions
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20
sysdeps/m68k/fpu/switch/switch.c
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@ -1,4 +1,4 @@
/* Copyright (C) 1991 Free Software Foundation, Inc. /* Copyright (C) 1991, 1992 Free Software Foundation, Inc.
This file is part of the GNU C Library. This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or The GNU C Library is free software; you can redistribute it and/or
@ -27,11 +27,8 @@ Cambridge, MA 02139, USA. */
#define TRAPSIG SIGILL #define TRAPSIG SIGILL
#endif #endif
/* Nonzero if we have determined whether or not there is a 68881. */ /* Zero if no 68881, one if we have a 68881, or -1 if we don't know yet. */
static int tested_fpu = 0; static int have_fpu = -1;
/* Nonzero if we have a 68881. */
static int have_fpu;
/* Signal handler for the trap that happens if we don't have a 68881. */ /* Signal handler for the trap that happens if we don't have a 68881. */
@ -53,10 +50,10 @@ DEFUN(__68881_switch, (dummy), int dummy)
struct switch_caller *CONST caller struct switch_caller *CONST caller
= (struct switch_caller *) (((short int *) *return_address_location) - 1); = (struct switch_caller *) (((short int *) *return_address_location) - 1);
if (!tested_fpu) if (have_fpu < 0)
{ {
/* Figure out whether or not we have a 68881. */ /* Figure out whether or not we have a 68881. */
__sighandler_t handler = signal(TRAPSIG, trap); __sighandler_t handler = signal (TRAPSIG, trap);
if (handler == SIG_ERR) if (handler == SIG_ERR)
/* We can't figure it out, so assume we don't have a 68881. /* We can't figure it out, so assume we don't have a 68881.
This assumption will never cause us any problems other than This assumption will never cause us any problems other than
@ -70,14 +67,11 @@ DEFUN(__68881_switch, (dummy), int dummy)
If we don't have one, this will trap and the signal handler If we don't have one, this will trap and the signal handler
will clear `have_fpu'. */ will clear `have_fpu'. */
have_fpu = 1; have_fpu = 1;
asm("fnop"); asm ("fnop");
/* Restore the old signal handler. */ /* Restore the old signal handler. */
(void) signal(TRAPSIG, handler); (void) signal (TRAPSIG, handler);
} }
/* Say that we've tested for a 68881, so we only do it once. */
tested_fpu = 1;
} }
/* Modify the caller to be a jump to the appropriate address. */ /* Modify the caller to be a jump to the appropriate address. */