Home | History | Annotate | Line # | Download | only in gen 
      1 /*	$NetBSD: modf.S,v 1.11 2009/12/14 01:07:42 matt Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1991, 1993, 1995
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * This code is derived from software contributed to Berkeley by
      8  * Ralph Campbell.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  * 3. Neither the name of the University nor the names of its contributors
     19  *    may be used to endorse or promote products derived from this software
     20  *    without specific prior written permission.
     21  *
     22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     32  * SUCH DAMAGE.
     33  */
     34 
     35 #include <mips/asm.h>
     36 
     37 #if defined(LIBC_SCCS) && !defined(lint)
     38 #if 0
     39 	RCSID("from: @(#)modf.s	8.1 (Berkeley) 6/4/93")
     40 #else
     41 	RCSID("$NetBSD: modf.S,v 1.11 2009/12/14 01:07:42 matt Exp $")
     42 #endif
     43 #endif /* LIBC_SCCS and not lint */
     44 
     45 /*
     46  * double modf(val, iptr)
     47  *	double val, *iptr;
     48  * returns: xxx and n (in *iptr) where val == n.xxx
     49  */
     50 LEAF(modf)
     51 	cfc1	t0, $31			# get the control register
     52 	li.d	$f2, 4503599627370496e0 # f2 <- 2^52
     53 
     54 	or	t1, t0, 0x3		# set rounding mode to round to zero
     55 	xor	t1, t1, 0x2		#  (i.e., 01)
     56 	ctc1	t1, $31
     57 
     58 	mov.d	$f0, $f12		# f0 <- f12
     59 	abs.d	$f4, $f12		# f4 <- |f12|
     60 	c.olt.d $f4, $f2		# f4 ? < f2
     61 	bc1f	1f			# leave f0 alone if Nan, infinity
     62 					# or >=2^52
     63 	c.eq.d	$f12,$f4		# was f12 positive ?
     64 	add.d	$f4,$f2,$f4		# round off to integer
     65 	bc1f	2f			# No -> will have to negate result
     66 	sub.d	$f0,$f4,$f2		# Remove fudge factor
     67 	j	1f			# integer fraction got
     68 2:
     69 	sub.d	$f0,$f2,$f4		# Remove fudge factor and negate
     70 1:
     71 	ctc1	t0, $31			# restore old rounding mode
     72 	s.d	$f0, 0(a2)		# save the integer part
     73 	sub.d	$f0, $f12, $f0		# subtract val - integer part
     74 	j	ra
     75 END(modf)
     76