/* * needs workspace of (size*2) words */ static void mpprndbits(mpbarrett* p, size_t bits, size_t lsbset, const mpnumber* min, const mpnumber* max, randomGeneratorContext* rc, mpw* wksp) { register size_t size = p->size; register size_t msbclr = MP_WORDS_TO_BITS(size) - bits; /* assume that mpbits(max) == bits */ /* calculate k=max-min; generate q such that 0 <= q <= k; then set p = q + min */ /* for the second step, set the appropriate number of bits */ if (max) { mpsetx(size, wksp, max->size, max->data); } else { mpfill(size, wksp, MP_ALLMASK); wksp[0] &= (MP_ALLMASK >> msbclr); } if (min) { mpsetx(size, wksp+size, min->size, min->data); } else { mpzero(size, wksp+size); wksp[size] |= (MP_MSBMASK >> msbclr); } mpsub(size, wksp, wksp+size); rc->rng->next(rc->param, (byte*) p->modl, MP_WORDS_TO_BYTES(size)); p->modl[0] &= (MP_ALLMASK >> msbclr); while (mpgt(size, p->modl, wksp)) mpsub(size, p->modl, wksp); mpadd(size, p->modl, wksp+size); if (lsbset) p->modl[size-1] |= (MP_ALLMASK >> (MP_WBITS - lsbset)); }
static int Zmpbinv_w(const mpbarrett* b, size_t xsize, const mpw* xdata, mpw* result, mpw* wksp) { size_t ysize = b->size+1; size_t ubits, vbits; int k = 0; mpw* u = wksp; mpw* v = u+ysize; mpw* A = v+ysize; mpw* B = A+ysize; mpw* C = B+ysize; mpw* D = C+ysize; mpsetx(ysize, u, xsize, xdata); mpsetx(ysize, v, b->size, b->modl); mpsetw(ysize, A, 1); mpzero(ysize, B); mpzero(ysize, C); mpsetw(ysize, D, 1); for (k = 0; mpeven(ysize, u) && mpeven(ysize, v); k++) { mpdivtwo(ysize, u); mpdivtwo(ysize, v); } if (mpeven(ysize, u)) (void) mpadd(ysize, u, v); if (_debug < 0) fprintf(stderr, " u: "), mpfprintln(stderr, ysize, u); if (_debug < 0) fprintf(stderr, " v: "), mpfprintln(stderr, ysize, v); if (_debug < 0) fprintf(stderr, " A: "), mpfprintln(stderr, ysize, A); if (_debug < 0) fprintf(stderr, " B: "), mpfprintln(stderr, ysize, B); if (_debug < 0) fprintf(stderr, " C: "), mpfprintln(stderr, ysize, C); if (_debug < 0) fprintf(stderr, " D: "), mpfprintln(stderr, ysize, D); ubits = vbits = MP_WORDS_TO_BITS(ysize); do { while (mpeven(ysize, v)) { mpsdivtwo(ysize, v); vbits -= 1; if (mpodd(ysize, C)) { (void) mpaddx(ysize, C, b->size, b->modl); (void) mpsubx(ysize, D, xsize, xdata); } mpsdivtwo(ysize, C); mpsdivtwo(ysize, D); if (_debug < 0) fprintf(stderr, "-->> v: "), mpfprintln(stderr, ysize, v); } if (ubits >= vbits) { mpw* swapu; size_t swapi; if (_debug < 0) fprintf(stderr, "--> (swap u <-> v)\n"); swapu = u; u = v; v = swapu; swapi = ubits; ubits = vbits; vbits = swapi; swapu = A; A = C; C = swapu; swapu = B; B = D; D = swapu; } if (!((u[ysize-1] + v[ysize-1]) & 0x3)) { if (_debug < 0) fprintf(stderr, "--> (even parity)\n"); mpadd(ysize, v, u); mpadd(ysize, C, A); mpadd(ysize, D, B); } else { if (_debug < 0) fprintf(stderr, "--> (odd parity)\n"); mpsub(ysize, v, u); mpsub(ysize, C, A); mpsub(ysize, D, B); } if (_debug < 0) fprintf(stderr, " v: "), mpfprintln(stderr, ysize, v); if (_debug < 0) fprintf(stderr, " C: "), mpfprintln(stderr, ysize, C); if (_debug < 0) fprintf(stderr, " D: "), mpfprintln(stderr, ysize, D); vbits++; } while (mpnz(ysize, v)); #ifdef NOTYET if (!mpisone(ysize, u)) return 0; #endif if (result) { mpsetx(b->size, result, ysize, A); /*@-usedef@*/ if (*A & 0x80000000) (void) mpneg(b->size, result); /*@=usedef@*/ while (--k > 0) mpadd(b->size, result, result); } fprintf(stderr, "=== EXIT: "), mpfprintln(stderr, b->size, result); fprintf(stderr, " u: "), mpfprintln(stderr, ysize, u); fprintf(stderr, " v: "), mpfprintln(stderr, ysize, v); fprintf(stderr, " A: "), mpfprintln(stderr, ysize, A); fprintf(stderr, " B: "), mpfprintln(stderr, ysize, B); fprintf(stderr, " C: "), mpfprintln(stderr, ysize, C); fprintf(stderr, " D: "), mpfprintln(stderr, ysize, D); return 1; }