1/* 2 * Copyright (c) 1983, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 */ 29 30/* 31 * double ldexp (value, exp) 32 * double value; 33 * int exp; 34 * 35 * Ldexp returns value*2**exp, if that result is in range. 36 * If underflow occurs, it returns zero. If overflow occurs, 37 * it returns a value of appropriate sign and largest 38 * possible magnitude. In case of either overflow or underflow, 39 * errno is set to ERANGE. Note that errno is not modified if 40 * no error occurs. 41 */ 42 43#include "DEFS.h" 44#include "assym.h" 45 46#if defined(LIBC_SCCS) && !defined(lint) 47 /*.asciz "@(#)ldexp.s 8.1 (Berkeley) 6/4/93" */ 48RCSID("$NetBSD: ldexp.S,v 1.7 2011/01/25 02:38:15 matt Exp $") 49#endif /* LIBC_SCCS and not lint */ 50 51#ifndef _REENTRANT 52 .globl _C_LABEL(errno) 53#endif 54 55ENTRY(ldexp, 0) 56 movd 4(%ap),%r0 /* fetch "value" */ 57 extzv $7,$8,%r0,%r2 /* %r2 := biased exponent */ 58 jeql 1f /* if zero, done */ 59 60 addl2 12(%ap),%r2 /* %r2 := new biased exponent */ 61 jleq 2f /* if <= 0, underflow */ 62 cmpl %r2,$256 /* otherwise check if too big */ 63 jgeq 3f /* jump if overflow */ 64 insv %r2,$7,$8,%r0 /* put exponent back in result */ 651: 66 ret 672: 68 clrd %r0 69 jbr 1f 703: 71 /* 72 * The largest number that can be represented in a long floating 73 * number. This is given in hex in order to avoid floating 74 * conversions 75 */ 76 movq $0x7fffffffffffffff,%r0 /* largest possible floating magnitude */ 77 jbc $15,4(%ap),1f /* jump if argument was positive */ 78 mnegd %r0,%r0 /* if arg < 0, make result negative */ 791: 80#ifdef _REENTRANT 81 pushl %r0 82 calls $0,_C_LABEL(__errno) 83 movl $ ERANGE,(%r0) 84 movl (%sp)+,%r0 85#else 86 movl $ ERANGE,_C_LABEL(errno) 87#endif 88 ret 89END(ldexp) 90