s_fabsl.s

glibc 库, 不仅可以学习使用库函数,还可以学习函数的具体实现,是提高功力的好资料

/* Copy a sign bit between floating-point values.
   IBM extended format long double version.
   Copyright (C) 2004, 2006 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 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
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307 USA.  */

#include <sysdep.h>
#include <math_ldbl_opt.h>

ENTRY(__fabsl)
/* long double [f1,f2] fabs (long double [f1,f2] x);
   fabs(x,y) returns a value with the magnitude of x and
   with the sign bit of y.  */
	fmr	fp0,fp1
	fabs	fp1,fp1
	fcmpu	cr1,fp0,fp1
	beqlr	cr1
	fneg	fp2,fp2
	blr
END (__fabsl)

long_double_symbol (libm, __fabsl, fabsl)