e_exp.S revision 1.14
1 /* $NetBSD: e_exp.S,v 1.14 2008/06/23 10:24:13 drochner Exp $ */ 2 3 /* 4 * Copyright (c) 1993,94 Winning Strategies, Inc. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by Winning Strategies, Inc. 18 * 4. The name of the author may not be used to endorse or promote products 19 * derived from this software without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 22 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 23 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 24 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 26 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 27 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 28 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 29 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 30 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 31 */ 32 33 /* 34 * Written by: 35 * J.T. Conklin (jtc (at) wimsey.com), Winning Strategies, Inc. 36 */ 37 38 #include <machine/asm.h> 39 40 #include "abi.h" 41 42 RCSID("$NetBSD: e_exp.S,v 1.14 2008/06/23 10:24:13 drochner Exp $") 43 #if 0 44 RCSID("$FreeBSD: src/lib/msun/i387/e_exp.S,v 1.8.2.1 2000/07/10 09:16:28 obrien Exp $") 45 #endif 46 47 /* e^x = 2^(x * log2(e)) */ 48 ENTRY(__ieee754_exp) 49 XMM_ONE_ARG_DOUBLE_PROLOGUE 50 /* 51 * If x is +-Inf, then the subtraction would give Inf-Inf = NaN. 52 * Avoid this. Also avoid it if x is NaN for convenience. 53 */ 54 movl ARG_DOUBLE_ONE_MSW, %eax 55 andl $0x7fffffff, %eax 56 cmpl $0x7ff00000, %eax 57 jae x_Inf_or_NaN 58 59 fldl ARG_DOUBLE_ONE 60 61 /* 62 * Ensure that the rounding mode is to nearest (to give the smallest 63 * possible fraction) and that the precision is as high as possible. 64 * We may as well mask interrupts if we switch the mode. 65 */ 66 #define CWSTORE_SAV ARG_DOUBLE_ONE_LSW /* XXX overwrites the argument */ 67 #define CWSTORE_TMP ARG_DOUBLE_ONE_MSW 68 fstcw CWSTORE_SAV 69 movl CWSTORE_SAV, %eax 70 andl $0x0f00, %eax 71 cmpl $0x0300, %eax /* RC == 0 && PC == 3? */ 72 je 1f /* jump if mode is good */ 73 movl $0x137f, CWSTORE_TMP 74 fldcw CWSTORE_TMP 75 1: 76 fldl2e 77 fmulp /* x * log2(e) */ 78 fst %st(1) 79 frndint /* int(x * log2(e)) */ 80 fst %st(2) 81 fsubrp /* fract(x * log2(e)) */ 82 f2xm1 /* 2^(fract(x * log2(e))) - 1 */ 83 fld1 84 faddp /* 2^(fract(x * log2(e))) */ 85 fscale /* e^x */ 86 fstp %st(1) 87 je 1f 88 fldcw CWSTORE_SAV 89 1: 90 XMM_DOUBLE_EPILOGUE 91 ret 92 x_Inf_or_NaN: 93 /* 94 * Return 0 if x is -Inf. Otherwise just return x, although the 95 * C version would return (x + x) (Real Indefinite) if x is a NaN. 96 */ 97 cmpl $0xfff00000, ARG_DOUBLE_ONE_MSW 98 jne x_not_minus_Inf 99 cmpl $0, ARG_DOUBLE_ONE_LSW 100 jne x_not_minus_Inf 101 fldz 102 XMM_DOUBLE_EPILOGUE 103 ret 104 105 x_not_minus_Inf: 106 fldl ARG_DOUBLE_ONE 107 XMM_DOUBLE_EPILOGUE 108 ret 109
Indexes created Tue Sep 30 11:09:46 GMT 2025