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/* Copyright 2001-4 tim goetze <tim@quitte.de> -- see 'COPYING'. */
/* class that sets the FP rounding mode to 'truncate' in the constructor
* and loads the previous FP conrol word in the destructor.
*
* i386 implementation only, on other architectures this is a no-op.
*/
#ifndef _DSP_FP_TRUNCATE_MODE_H_
#define _DSP_FP_TRUNCATE_MODE_H_
#ifdef __i386__
#define fstcw(i) \
__asm__ __volatile__ ("fstcw %0" : "=m" (i))
#define fldcw(i) \
__asm__ __volatile__ ("fldcw %0" : : "m" (i))
/* gcc chokes on __volatile__ sometimes. */
#define fistp(f,i) \
__asm__ ("fistpl %0" : "=m" (i) : "t" (f) : "st")
#else /* ! __i386__ */
#define fstcw(i)
#define fldcw(i)
#define fistp(f,i) \
i = (int) f
#endif
namespace DSP {
class FPTruncateMode
{
public:
int cw0, cw1; /* fp control word */
FPTruncateMode()
{
fstcw (cw0);
cw1 = cw0 | 0xC00;
fldcw (cw1);
}
~FPTruncateMode()
{
fldcw (cw0);
}
};
} /* namespace DSP */
#endif /* _DSP_FP_TRUNCATE_MODE_H_ */
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