Return to fpu_int.c CVS log

Up to [Isaki's NoNo m68k/m88k emulator] / nono / fpe

Annotation of nono/fpe/fpu_int.c, revision 1.1

1.1     ! root        1: /*     $NetBSD: fpu_int.c,v 1.12 2013/03/19 09:17:17 isaki Exp $       */
        !             2: 
        !             3: /*
        !             4:  * Copyright (c) 1995 Ken Nakata
        !             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:  *
        !            16:  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
        !            17:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
        !            18:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
        !            19:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
        !            20:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
        !            21:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
        !            22:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
        !            23:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
        !            24:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
        !            25:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
        !            26:  * SUCH DAMAGE.
        !            27:  *
        !            28:  *     @(#)fpu_int.c
        !            29:  */
        !            30: 
        !            31: #include "fpu_arith.h"
        !            32: #include "fpu_emulate.h"
        !            33: 
        !            34: /* FINTRZ - always round to zero */
        !            35: struct fpn *
        !            36: fpu_intrz(struct fpemu *fe)
        !            37: {
        !            38:        struct fpn *x = &fe->fe_f2;
        !            39:        int sh, clr, mask, i;
        !            40:        uint32_t mant[3];
        !            41: 
        !            42:        /* special cases first */
        !            43:        if (x->fp_class != FPC_NUM) {
        !            44:                return x;
        !            45:        }
        !            46:        /* when |x| < 1.0 */
        !            47:        if (x->fp_exp < 0) {
        !            48:                x->fp_class = FPC_ZERO;
        !            49:                x->fp_mant[0] = x->fp_mant[1] = x->fp_mant[2] = 0;
        !            50:                fe->fe_fpsr |= FPSR_INEX2;
        !            51:                return x;
        !            52:        }
        !            53: 
        !            54:        /* real work */
        !            55:        sh = FP_NMANT - 1 - x->fp_exp;
        !            56:        if (sh <= 0) {
        !            57:                return x;
        !            58:        }
        !            59: 
        !            60:        clr = 2 - sh / 32;
        !            61:        mask = (0xffffffff << (sh % 32));
        !            62: 
        !            63:        /* save */
        !            64:        for (i = 0; i < 3; i++) {
        !            65:                mant[i] = x->fp_mant[i];
        !            66:        }
        !            67: 
        !            68:        for (i = 2; i > clr; i--) {
        !            69:                x->fp_mant[i] = 0;
        !            70:        }
        !            71:        x->fp_mant[i] &= mask;
        !            72: 
        !            73:        /* check INEX2 */
        !            74:        for (i = 0; i < 3; i++) {
        !            75:                if (x->fp_mant[i] != mant[i]) {
        !            76:                        fe->fe_fpsr |= FPSR_INEX2;
        !            77:                }
        !            78:        }
        !            79: 
        !            80:        return x;
        !            81: }
        !            82: 
        !            83: /* FINT */
        !            84: struct fpn *
        !            85: fpu_int(struct fpemu *fe)
        !            86: {
        !            87:        struct fpn *x = &fe->fe_f2;
        !            88:        int rsh;
        !            89: 
        !            90:        /* special cases first */
        !            91:        if (x->fp_class != FPC_NUM) {
        !            92:                return x;
        !            93:        }
        !            94: 
        !            95:        rsh = FP_NMANT - 1 - x->fp_exp;
        !            96:        if (rsh <= FP_NG) {
        !            97:                return x;
        !            98:        }
        !            99: 
        !           100:        /* shift to the right */
        !           101:        x->fp_exp = 0;
        !           102:        fpu_shr(x, rsh - FP_NG);
        !           103: 
        !           104:        /* round according to FPCR round mode */
        !           105:        fpu_round(fe, x);
        !           106: 
        !           107:        /* shift it back to the left */
        !           108:        x->fp_exp = FP_NMANT - 1;
        !           109:        fpu_norm(x);
        !           110: 
        !           111:        return x;
        !           112: }

This archive runs on limited infrastructure. Preserving old code on modern bandwidth. Automated agents are requested to crawl responsibly.