sqroot.m4

来自「早期freebsd实现」· M4 代码 · 共 46 行

#
# Copyright (c) 1989, 1993
#	The Regents of the University of California.  All rights reserved.
#
# This code is derived from software contributed to Berkeley by
# Ozan Yigit.
#
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# modification, are permitted provided that the following conditions
# are met:
# 1. Redistributions of source code must retain the above copyright
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#    must display the following acknowledgement:
#	This product includes software developed by the University of
#	California, Berkeley and its contributors.
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#	@(#)sqroot.m4	8.1 (Berkeley) 6/6/93
#

define(square_root, 
	`ifelse(eval($1<0),1,negative-square-root,
			     `square_root_aux($1, 1, eval(($1+1)/2))')')
define(square_root_aux,
	`ifelse($3, $2, $3,
		$3, eval($1/$2), $3,
		`square_root_aux($1, $3, eval(($3+($1/$3))/2))')')