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