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40 lines
778 B
ArmAsm
40 lines
778 B
ArmAsm
/*
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* Written by J.T. Conklin <jtc@netbsd.org>.
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* Changes for long double by Ulrich Drepper <drepper@cygnus.com>
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* Adapted for x86-64 by Andreas Jaeger <aj@suse.de>.
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* Public domain.
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*/
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#include <machine/asm.h>
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ENTRY(__ieee754_ilogbl)
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fldt 8(%rsp)
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/* I added the following ugly construct because ilogb(+-Inf) is
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required to return INT_MAX in ISO C99.
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-- jakub@redhat.com. */
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fxam /* Is NaN or +-Inf? */
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fstsw %ax
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movb $0x45, %dh
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andb %ah, %dh
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cmpb $0x05, %dh
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je 1f /* Is +-Inf, jump. */
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cmpb $0x40, %dh
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je 2f /* Is +-Inf, jump. */
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fxtract
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fstp %st
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fistpl -4(%rsp)
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fwait
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movl -4(%rsp),%eax
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ret
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1: fstp %st
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movl $0x7fffffff, %eax
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ret
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2: fstp %st
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movl $0x80000000, %eax /* FP_ILOGB0 */
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ret
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END (__ieee754_ilogbl)
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