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Annotation of sys/arch/hppa/spmath/divsfm.c, Revision 1.1.1.1

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: }