| 1 | /* |
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| 2 | * Public domain. |
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| 3 | */ |
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| 4 | |
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| 5 | #include <machine/asm.h> |
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| 6 | |
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| 7 | ENTRY(__ieee754_ilogbl) |
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| 8 | fldt 8(%rsp) |
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| 9 | /* I added the following ugly construct because ilogb(+-Inf) is |
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| 10 | required to return INT_MAX in ISO C99. |
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| 11 | -- jakub@redhat.com. */ |
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| 12 | fxam /* Is NaN or +-Inf? */ |
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| 13 | fstsw %ax |
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| 14 | movb $0x45, %dh |
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| 15 | andb %ah, %dh |
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| 16 | cmpb $0x05, %dh |
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| 17 | je 1f /* Is +-Inf, jump. */ |
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| 18 | cmpb $0x40, %dh |
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| 19 | je 2f /* Is +-Inf, jump. */ |
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| 20 | |
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| 21 | fxtract |
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| 22 | fstp %st |
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| 23 | |
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| 24 | fistpl -4(%rsp) |
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| 25 | fwait |
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| 26 | movl -4(%rsp),%eax |
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| 27 | |
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| 28 | ret |
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| 29 | |
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| 30 | 1: fstp %st |
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| 31 | movl $0x7fffffff, %eax |
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| 32 | ret |
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| 33 | 2: fstp %st |
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| 34 | movl $0x80000000, %eax /* FP_ILOGB0 */ |
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| 35 | ret |
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| 36 | END (__ieee754_ilogbl) |
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| 37 | |
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