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