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authorUlrich Drepper <drepper@redhat.com>1999-07-14 00:54:57 +0000
committerUlrich Drepper <drepper@redhat.com>1999-07-14 00:54:57 +0000
commitabfbdde177c3a7155070dda1b2cdc8292054cc26 (patch)
treee021306b596381fbf8311d2b7eb294e918ff17c8 /sysdeps/i386/fpu/e_acoshf.S
parent86421aa57ecfd70963ae66848bd6a6dd3b8e0fe6 (diff)
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Update.
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+/* ix87 specific implementation of arcsinh.
+   Copyright (C) 1996, 1997 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Ulrich Drepper <drepper@cygnus.com>, 1996.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Library General Public License as
+   published by the Free Software Foundation; either version 2 of the
+   License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Library General Public License for more details.
+
+   You should have received a copy of the GNU Library General Public
+   License along with the GNU C Library; see the file COPYING.LIB.  If not,
+   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+#include <machine/asm.h>
+
+#ifdef __ELF__
+	.section .rodata
+#else
+	.text
+#endif
+
+	.align ALIGNARG(4)
+	ASM_TYPE_DIRECTIVE(one,@object)
+one:	.double 1.0
+	ASM_SIZE_DIRECTIVE(one)
+	ASM_TYPE_DIRECTIVE(limit,@object)
+limit:	.double 0.29
+	ASM_SIZE_DIRECTIVE(limit)
+
+#ifdef PIC
+#define MO(op) op##@GOTOFF(%edx)
+#else
+#define MO(op) op
+#endif
+
+	.text
+ENTRY(__ieee754_acoshf)
+	movl	4(%esp), %ecx
+	cmpl	$0x3f800000, %ecx
+	jl	5f			// < 1 => invalid
+	fldln2				// log(2)
+	flds	4(%esp)			// x : log(2)
+	cmpl	$0x47000000, %ecx
+	ja	3f			// x > 2^14
+#ifdef	PIC
+	call	1f
+1:	popl	%edx
+	addl	$_GLOBAL_OFFSET_TABLE_+[.-1b], %edx
+#endif
+	cmpl	$0x40000000, %ecx
+	ja	4f			// x > 2
+
+	// 1 <= x <= 2 => y = log1p(x-1+sqrt(2*(x-1)+(x-1)^2))
+	fsubl	MO(one)			// x-1 : log(2)
+	fld	%st			// x-1 : x-1 : log(2)
+	fmul	%st(1)			// (x-1)^2 : x-1 : log(2)
+	fadd	%st(1)			// x-1+(x-1)^2 : x-1 : log(2)
+	fadd	%st(1)			// 2*(x-1)+(x-1)^2 : x-1 : log(2)
+	fsqrt				// sqrt(2*(x-1)+(x-1)^2) : x-1 : log(2)
+	faddp				// x-1+sqrt(2*(x-1)+(x-1)^2) : log(2)
+	fcoml	MO(limit)
+	fnstsw
+	sahf
+	ja	2f
+	fyl2xp1				// log1p(x-1+sqrt(2*(x-1)+(x-1)^2))
+	ret
+
+2:	faddl	MO(one)			// x+sqrt(2*(x-1)+(x-1)^2) : log(2)
+	fyl2x				// log(x+sqrt(2*(x-1)+(x-1)^2))
+	ret
+
+	// x > 2^14 => y = log(x) + log(2)
+	.align ALIGNARG(4)
+3:	fyl2x				// log(x)
+	fldln2				// log(2) : log(x)
+	faddp				// log(x)+log(2)
+	ret
+
+	// 2^28 > x > 2 => y = log(2*x - 1/(x+sqrt(x*x-1)))
+	.align ALIGNARG(4)
+4:	fld	%st			// x : x : log(2)
+	fadd	%st, %st(1)		// x : 2*x : log(2)
+	fld	%st			// x : x : 2*x : log(2)
+	fmul	%st(1)			// x^2 : x : 2*x : log(2)
+	fsubl	MO(one)			// x^2-1 : x : 2*x : log(2)
+	fsqrt				// sqrt(x^2-1) : x : 2*x : log(2)
+	faddp				// x+sqrt(x^2-1) : 2*x : log(2)
+	fdivrl	MO(one)			// 1/(x+sqrt(x^2-1)) : 2*x : log(2)
+	fsubrp				// 2*x+1/(x+sqrt(x^2)-1) : log(2)
+	fyl2x				// log(2*x+1/(x+sqrt(x^2-1)))
+	ret
+
+	// x < 1 => NaN
+	.align ALIGNARG(4)
+5:	fldz
+	fdiv	%st, %st(0)
+	ret
+END(__ieee754_acoshf)