| #include <math.h> | |
| /* 'fxam' sets FPU flags C3,C2,C0 'fstsw' stores: | |
| FP_NAN 001 0x0100 | |
| FP_NORMAL 010 0x0400 | |
| FP_INFINITE 011 0x0500 | |
| FP_ZERO 100 0x4000 | |
| FP_SUBNORMAL 110 0x4400 | |
| and sets C1 flag (signbit) if neg */ | |
| int __fpclassify (double _x){ | |
| unsigned short sw; | |
| __asm__ ( | |
| "fxam; fstsw %%ax;" | |
| : "=a" (sw) | |
| : "t" (_x) | |
| ); | |
| return sw & (FP_NAN | FP_NORMAL | FP_ZERO ); | |
| } |