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/*
* Written by J.T. Conklin <jtc@netbsd.org>.
* Public domain.
*/
#include <machine/asm.h>
RCSID("$NetBSD: s_ilogb.S,v 1.5 1995/10/12 15:53:09 jtc Exp $")
ENTRY(__ieee754_ilogb)
fldl 4(%esp)
/* I added the following ugly construct because ilogb(+-Inf) is
required to return INT_MAX in ISO C99.
-- jakub@redhat.com. */
fxam /* Is NaN or +-Inf? */
fstsw %ax
movb $0x45, %dh
andb %ah, %dh
cmpb $0x05, %dh
je 1f /* Is +-Inf, jump. */
cmpb $0x40, %dh
je 2f /* Is +-0, jump. */
fxtract
pushl %eax
cfi_adjust_cfa_offset (4)
fstp %st
fistpl (%esp)
fwait
popl %eax
cfi_adjust_cfa_offset (-4)
ret
1: fstp %st
movl $0x7fffffff, %eax
ret
2: fstp %st
movl $0x80000000, %eax /* FP_ILOGB0 */
ret
END (__ieee754_ilogb)
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