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/* $Id: ctrl87.c,v 1.2 1998/03/22 22:31:27 drd Exp $ */
/* GNUPLOT - ctrl87.c */
/*[
* Copyright 1986 - 1993, 1998 Thomas Williams, Colin Kelley
*
* Permission to use, copy, and distribute this software and its
* documentation for any purpose with or without fee is hereby granted,
* provided that the above copyright notice appear in all copies and
* that both that copyright notice and this permission notice appear
* in supporting documentation.
*
* Permission to modify the software is granted, but not the right to
* distribute the complete modified source code. Modifications are to
* be distributed as patches to the released version. Permission to
* distribute binaries produced by compiling modified sources is granted,
* provided you
* 1. distribute the corresponding source modifications from the
* released version in the form of a patch file along with the binaries,
* 2. add special version identification to distinguish your version
* in addition to the base release version number,
* 3. provide your name and address as the primary contact for the
* support of your modified version, and
* 4. retain our contact information in regard to use of the base
* software.
* Permission to distribute the released version of the source code along
* with corresponding source modifications in the form of a patch file is
* granted with same provisions 2 through 4 for binary distributions.
*
* This software is provided "as is" without express or implied warranty
* to the extent permitted by applicable law.
]*/
#define __CONTROL87_C__
#include "ctrl87.h"
/***** _control87 *****/
unsigned short _control87(unsigned short newcw, unsigned short mask)
{
unsigned short cw;
asm volatile(" \n\
wait \n\
fstcw %0 "
: /* outputs */ "=g" (cw)
: /* inputs */
);
if(mask) { /* mask is not 0 */
asm volatile(" \n\
mov %2, %%ax \n\
mov %3, %%bx \n\
and %%bx, %%ax \n\
not %%bx \n\
nop \n\
wait \n\
mov %1, %%dx \n\
and %%bx, %%dx \n\
or %%ax, %%dx \n\
mov %%dx, %0 \n\
wait \n\
fldcw %1 "
: /* outputs */ "=g" (cw)
: /* inputs */ "g" (cw), "g" (newcw), "g" (mask)
: /* registers */ "ax", "bx", "dx"
);
}
return cw;
} /* _control87 */
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