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Annotation of sys/arch/hppa/spmath/divsfm.c, Revision 1.1

1.1     ! nbrk        1: /*     $OpenBSD: divsfm.c,v 1.5 2002/05/07 22:19:30 mickey Exp $       */
        !             2: /*
        !             3:   (c) Copyright 1986 HEWLETT-PACKARD COMPANY
        !             4:   To anyone who acknowledges that this file is provided "AS IS"
        !             5:   without any express or implied warranty:
        !             6:       permission to use, copy, modify, and distribute this file
        !             7:   for any purpose is hereby granted without fee, provided that
        !             8:   the above copyright notice and this notice appears in all
        !             9:   copies, and that the name of Hewlett-Packard Company not be
        !            10:   used in advertising or publicity pertaining to distribution
        !            11:   of the software without specific, written prior permission.
        !            12:   Hewlett-Packard Company makes no representations about the
        !            13:   suitability of this software for any purpose.
        !            14: */
        !            15: /* @(#)divsfm.c: Revision: 1.6.88.1 Date: 93/12/07 15:05:51 */
        !            16:
        !            17: #include "md.h"
        !            18:
        !            19: void
        !            20: divsfm(opnd1,opnd2,result)
        !            21:        int opnd1, opnd2;
        !            22:        struct mdsfu_register *result;
        !            23: {
        !            24:        register int sign, op1_sign;
        !            25:
        !            26:        /* check divisor for zero */
        !            27:        if (opnd2 == 0) {
        !            28:                overflow = TRUE;
        !            29:                return;
        !            30:        }
        !            31:
        !            32:        /* get sign of result */
        !            33:        sign = opnd1 ^ opnd2;
        !            34:
        !            35:        /* get absolute value of operands */
        !            36:        if (opnd1 < 0) {
        !            37:                opnd1 = -opnd1;
        !            38:                op1_sign = TRUE;
        !            39:        }
        !            40:        else op1_sign = FALSE;
        !            41:        if (opnd2 < 0) opnd2 = -opnd2;
        !            42:
        !            43:        /*
        !            44:         * check for overflow
        !            45:         *
        !            46:         * if abs(opnd1) < 0, then opnd1 = -2**31
        !            47:         * and abs(opnd1) >= abs(opnd2) always
        !            48:         */
        !            49:        if (opnd1 >= opnd2 || opnd1 < 0) {
        !            50:                /* check for opnd2 = -2**31 */
        !            51:                if (opnd2 < 0 && opnd1 != opnd2) {
        !            52:                        result_hi = 0;          /* remainder = 0 */
        !            53:                        result_lo = opnd1 << 1;
        !            54:                }
        !            55:                else {
        !            56:                        overflow = TRUE;
        !            57:                        return;
        !            58:                }
        !            59:        }
        !            60:        else {
        !            61:                /* do the divide */
        !            62:                divu(opnd1,0,opnd2,result);
        !            63:
        !            64:                /* return positive residue */
        !            65:                if (op1_sign && result_hi) {
        !            66:                        result_hi = opnd2 - result_hi;
        !            67:                        result_lo++;
        !            68:                }
        !            69:        }
        !            70:
        !            71:        /* check for overflow */
        !            72:        if (result_lo < 0) {
        !            73:                overflow = TRUE;
        !            74:                return;
        !            75:        }
        !            76:        overflow = FALSE;
        !            77:
        !            78:        /* return appropriately signed result */
        !            79:        if (sign<0) result_lo = -result_lo;
        !            80:        return;
        !            81: }