31 lines
580 B
C
31 lines
580 B
C
#include <fenv.h>
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long double
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roundl (long double x) {
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long double retval;
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unsigned short saved_cw, _cw;
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__asm__ (
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"fnstcw %0;"
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: "=m" (saved_cw)
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); /* save control word */
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_cw = ~(FE_TONEAREST | FE_DOWNWARD | FE_UPWARD | FE_TOWARDZERO)
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| (x > 0.0 ? FE_UPWARD : FE_DOWNWARD); /* round away from zero */
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__asm__ (
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"fldcw %0;"
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:
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: "m" (_cw)
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); /* load the rounding control */
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__asm__ (
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"frndint;"
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: "=t" (retval)
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: "0" (x)
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); /* do the rounding */
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__asm__ (
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"fldcw %0;"
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:
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: "m" (saved_cw)
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); /* restore control word */
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return retval;
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}
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