?? e_log10l.s
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/* * Written by J.T. Conklin <jtc@netbsd.org>. * Public domain. * * Adapted for `long double' by Ulrich Drepper <drepper@cygnus.com>. * * Changed to use fyl2xp1 for values near 1, <drepper@cygnus.com>. * Adapted for x86-64 by Andreas Jaeger <aj@suse.de>. */#include <machine/asm.h>RCSID("$NetBSD: $")#ifdef __ELF__ .section .rodata#else .text#endif .align ALIGNARG(4) ASM_TYPE_DIRECTIVE(one,@object)one: .double 1.0 ASM_SIZE_DIRECTIVE(one) /* It is not important that this constant is precise. It is only a value which is known to be on the safe side for using the fyl2xp1 instruction. */ ASM_TYPE_DIRECTIVE(limit,@object)limit: .double 0.29 ASM_SIZE_DIRECTIVE(limit)#ifdef PIC#define MO(op) op##(%rip)#else#define MO(op) op#endif .textENTRY(__ieee754_log10l) fldlg2 // log10(2) fldt 8(%rsp) // x : log10(2) fxam fnstsw fld %st // x : x : log10(2) testb $1, %ah jnz 3f // in case x is NaN or 盜nf4: fsubl MO(one) // x-1 : x : log10(2) fld %st // x-1 : x-1 : x : log10(2) fabs // |x-1| : x-1 : x : log10(2) fcompl MO(limit) // x-1 : x : log10(2) fnstsw // x-1 : x : log10(2) andb $0x45, %ah jz 2f fstp %st(1) // x-1 : log10(2) fyl2xp1 // log10(x) ret2: fstp %st(0) // x : log10(2) fyl2x // log10(x) ret3: testb $4, %ah jnz 4b // in case x is 盜nf fstp %st(1) fstp %st(1) retEND(__ieee754_log10l)
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