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 */ 50LEAF(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 682: 69 sub.d $f0,$f2,$f4 # Remove fudge factor and negate 701: 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 75END(modf) 76