newlib-cygwin/winsup/mingw/mingwex/math/trunc.c

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#include <fenv.h>
#include <math.h>
double
trunc (double _x){
double retval;
unsigned short saved_cw;
unsigned short tmp_cw;
__asm__ ("fnstcw %0;" : "=m" (saved_cw)); /* save FPU control word */
tmp_cw = (saved_cw & ~(FE_TONEAREST | FE_DOWNWARD | FE_UPWARD | FE_TOWARDZERO))
| FE_TOWARDZERO;
__asm__ ("fldcw %0;" : : "m" (tmp_cw));
__asm__ ("frndint;" : "=t" (retval) : "0" (_x)); /* round towards zero */
__asm__ ("fldcw %0;" : : "m" (saved_cw) ); /* restore saved control word */
return retval;
}