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#include <math.h> int __isnan (double _x) { unsigned short _sw; __asm__ ("fxam;" "fstsw %%ax": "=a" (_sw) : "t" (_x)); return (_sw & (FP_NAN | FP_NORMAL | FP_INFINITE | FP_ZERO | FP_SUBNORMAL)) == FP_NAN; } #undef isnan int __attribute__ ((alias ("__isnan"))) isnan (double);