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Annotation of coherent/d/usr/lib/libmp/madd.c, revision 1.1

1.1     ! root        1: #include "mprec.h"
        !             2: #include <assert.h>
        !             3: 
        !             4: 
        !             5: /*
        !             6:  *     Madd adds the mints pointed to by "a" and "b" and puts the result
        !             7:  *     into the mint pointed to by "c".  Note that it assumes that the
        !             8:  *     contents of the mint pointed to by "c" are valid.  Also note that
        !             9:  *     there is no assumption made on the distinctness of "a", "b" and "c".
        !            10:  */
        !            11: void
        !            12: madd(a, b, c)
        !            13: mint *a, *b, *c;
        !            14: {
        !            15:        register char *rp, *ap, *bp;
        !            16:        char *limit;
        !            17:        char asign, bsign;
        !            18:        mint *temp;
        !            19:        mint res;
        !            20: 
        !            21:        /* make a the bigger of the two */
        !            22:        if (a->len < b->len) {
        !            23:                temp = a;
        !            24:                a = b;
        !            25:                b = temp;
        !            26:        }
        !            27: 
        !            28:        /* allocate new value */
        !            29:        rp = (char *)mpalc(a->len + 1);
        !            30:        res.val = rp;
        !            31:        res.len = a->len + 1;
        !            32: 
        !            33:        ap = a->val;
        !            34:        bp = b->val;
        !            35: 
        !            36:        /* add a and b over range of both */
        !            37:        limit = bp + b->len;
        !            38:        while (bp < limit)
        !            39:                *rp++ = *ap++ + *bp++;
        !            40: 
        !            41:        /* add sign extended b to rest of a */
        !            42:        bsign = (ispos(b) ? 00 : NEFL);
        !            43:        limit = a->val + a->len;
        !            44:        while (ap < limit)
        !            45:                *rp++ = *ap++ + bsign;
        !            46: 
        !            47:        /* add sign of a and sign of b and put sum in lead digit of res */
        !            48:        asign = (ispos(a) ? 00 : NEFL);
        !            49:        *rp = asign + bsign;
        !            50:        assert(rp == res.val + res.len - 1);
        !            51: 
        !            52:        norm(&res);
        !            53:        mpfree(c->val);
        !            54:        *c = res;
        !            55: }
        !            56: 
        !            57: 
        !            58: /*
        !            59:  *     Msub subtracts the mint pointed to by "b" from that pointed at
        !            60:  *     by "a" and stores the result in that pointed to by "c".  Note
        !            61:  *     that there is no assumption made on the distinctness of "a", "b"
        !            62:  *     and "c".
        !            63:  */
        !            64: 
        !            65: void
        !            66: msub(a, b, c)
        !            67: mint *a, *b, *c;
        !            68: {
        !            69:        mint temp;
        !            70: 
        !            71:        minit(&temp);
        !            72:        mneg(b, &temp);
        !            73:        madd(a, &temp, c);
        !            74:        mpfree(temp.val);
        !            75: }

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