vm: use tabs instead of spaces in bignum_gcd.
John Benediktsson
parent
54fd95cd81
commit
b541986b4e
376
vm/bignum.cpp
376
vm/bignum.cpp
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@ -1720,225 +1720,225 @@ int factor_vm::bignum_unsigned_logbitp(int shift, bignum * bignum)
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/* Allocates memory */
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bignum * factor_vm::bignum_gcd(bignum * a, bignum * b)
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{
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GC_BIGNUM(a);
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GC_BIGNUM(b);
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bignum * d;
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bignum_length_type size_a, size_b;
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bignum_digit_type * scan_a, * scan_b, * scan_d, * a_end, * b_end;
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GC_BIGNUM(a);
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GC_BIGNUM(b);
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bignum * d;
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bignum_length_type size_a, size_b;
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bignum_digit_type * scan_a, * scan_b, * scan_d, * a_end, * b_end;
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if (BIGNUM_NEGATIVE_P (a)) {
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size_a = BIGNUM_LENGTH (a);
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d = allot_bignum (size_a, 0);
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scan_d = BIGNUM_START_PTR (d);
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scan_a = BIGNUM_START_PTR (a);
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a_end = scan_a + size_a;
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while (scan_a < a_end)
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(*scan_d++) = (*scan_a++);
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a = d;
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}
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if (BIGNUM_NEGATIVE_P (a)) {
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size_a = BIGNUM_LENGTH (a);
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d = allot_bignum (size_a, 0);
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scan_d = BIGNUM_START_PTR (d);
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scan_a = BIGNUM_START_PTR (a);
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a_end = scan_a + size_a;
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while (scan_a < a_end)
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(*scan_d++) = (*scan_a++);
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a = d;
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}
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if (BIGNUM_NEGATIVE_P (b)) {
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size_b = BIGNUM_LENGTH (b);
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d = allot_bignum (size_b, 0);
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scan_d = BIGNUM_START_PTR (d);
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scan_b = BIGNUM_START_PTR (b);
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b_end = scan_b + size_b;
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while (scan_b < b_end)
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(*scan_d++) = (*scan_b++);
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b = d;
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}
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if (BIGNUM_NEGATIVE_P (b)) {
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size_b = BIGNUM_LENGTH (b);
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d = allot_bignum (size_b, 0);
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scan_d = BIGNUM_START_PTR (d);
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scan_b = BIGNUM_START_PTR (b);
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b_end = scan_b + size_b;
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while (scan_b < b_end)
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(*scan_d++) = (*scan_b++);
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b = d;
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}
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if (bignum_compare(a, b) == bignum_comparison_less) {
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std::swap(a, b);
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}
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if (bignum_compare(a, b) == bignum_comparison_less) {
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std::swap(a, b);
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}
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while (BIGNUM_LENGTH (b) != 0) {
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d = bignum_remainder (a, b);
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GC_BIGNUM(d);
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if (d == BIGNUM_OUT_OF_BAND) {
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return d;
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}
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a = b;
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b = d;
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}
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while (BIGNUM_LENGTH (b) != 0) {
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d = bignum_remainder (a, b);
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GC_BIGNUM(d);
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if (d == BIGNUM_OUT_OF_BAND) {
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return d;
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}
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a = b;
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b = d;
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}
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return a;
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return a;
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}
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#else
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/* Allocates memory */
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bignum * factor_vm::bignum_gcd(bignum * a, bignum * b)
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{
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GC_BIGNUM(a);
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GC_BIGNUM(b);
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bignum *c, *d, *e, *f;
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bignum_twodigit_type x, y, q, s, t, A, B, C, D;
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int nbits, k;
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bignum_length_type size_a, size_b, size_c;
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bignum_digit_type *scan_a, *scan_b, *scan_c, *scan_d;
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bignum_digit_type *a_end, *b_end, *c_end;
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GC_BIGNUM(a);
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GC_BIGNUM(b);
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bignum *c, *d, *e, *f;
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bignum_twodigit_type x, y, q, s, t, A, B, C, D;
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int nbits, k;
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bignum_length_type size_a, size_b, size_c;
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bignum_digit_type *scan_a, *scan_b, *scan_c, *scan_d;
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bignum_digit_type *a_end, *b_end, *c_end;
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/* clone the bignums so we can modify them in-place */
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size_a = BIGNUM_LENGTH (a);
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c = allot_bignum (size_a, 0);
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scan_a = BIGNUM_START_PTR (a);
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a_end = scan_a + size_a;
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GC_BIGNUM(c);
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scan_c = BIGNUM_START_PTR (c);
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while (scan_a < a_end)
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(*scan_c++) = (*scan_a++);
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a = c;
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size_b = BIGNUM_LENGTH (b);
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d = allot_bignum (size_b, 0);
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scan_b = BIGNUM_START_PTR (b);
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b_end = scan_b + size_b;
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GC_BIGNUM(d);
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scan_d = BIGNUM_START_PTR (d);
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while (scan_b < b_end)
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(*scan_d++) = (*scan_b++);
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b = d;
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/* clone the bignums so we can modify them in-place */
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size_a = BIGNUM_LENGTH (a);
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c = allot_bignum (size_a, 0);
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scan_a = BIGNUM_START_PTR (a);
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a_end = scan_a + size_a;
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GC_BIGNUM(c);
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scan_c = BIGNUM_START_PTR (c);
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while (scan_a < a_end)
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(*scan_c++) = (*scan_a++);
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a = c;
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size_b = BIGNUM_LENGTH (b);
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d = allot_bignum (size_b, 0);
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scan_b = BIGNUM_START_PTR (b);
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b_end = scan_b + size_b;
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GC_BIGNUM(d);
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scan_d = BIGNUM_START_PTR (d);
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while (scan_b < b_end)
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(*scan_d++) = (*scan_b++);
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b = d;
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/* Initial reduction: make sure that 0 <= b <= a. */
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if (bignum_compare(a, b) == bignum_comparison_less) {
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std::swap(a, b);
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std::swap(size_a, size_b);
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}
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/* Initial reduction: make sure that 0 <= b <= a. */
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if (bignum_compare(a, b) == bignum_comparison_less) {
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std::swap(a, b);
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std::swap(size_a, size_b);
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}
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while (size_a > 1) {
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nbits = log2 (BIGNUM_REF (a, size_a-1));
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x = ((BIGNUM_REF (a, size_a-1) << (BIGNUM_DIGIT_LENGTH - nbits)) |
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(BIGNUM_REF (a, size_a-2) >> nbits));
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y = ((size_b >= size_a - 1 ? BIGNUM_REF (b, size_a-2) >> nbits : 0) |
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(size_b >= size_a ? BIGNUM_REF (b, size_a-1) << (BIGNUM_DIGIT_LENGTH - nbits) : 0));
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while (size_a > 1) {
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nbits = log2 (BIGNUM_REF (a, size_a-1));
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x = ((BIGNUM_REF (a, size_a-1) << (BIGNUM_DIGIT_LENGTH - nbits)) |
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(BIGNUM_REF (a, size_a-2) >> nbits));
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y = ((size_b >= size_a - 1 ? BIGNUM_REF (b, size_a-2) >> nbits : 0) |
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(size_b >= size_a ? BIGNUM_REF (b, size_a-1) << (BIGNUM_DIGIT_LENGTH - nbits) : 0));
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/* inner loop of Lehmer's algorithm; */
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A = 1; B = 0; C = 0; D = 1;
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for (k=0 ;; k++) {
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if (y - C == 0)
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break;
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A = 1; B = 0; C = 0; D = 1;
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for (k=0 ;; k++) {
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if (y - C == 0)
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break;
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q = (x + (A - 1)) / (y - C);
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q = (x + (A - 1)) / (y - C);
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s = B + (q * D);
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t = x - (q * y);
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s = B + (q * D);
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t = x - (q * y);
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if (s > t)
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break;
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if (s > t)
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break;
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x = y;
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y = t;
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x = y;
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y = t;
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t = A + (q * C);
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t = A + (q * C);
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A = D; B = C; C = s; D = t;
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}
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A = D; B = C; C = s; D = t;
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}
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if (k == 0) {
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/* no progress; do a Euclidean step */
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if (size_b == 0) {
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return bignum_trim (a);
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}
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e = bignum_trim (a);
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GC_BIGNUM(e);
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f = bignum_trim (b);
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GC_BIGNUM(f);
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c = bignum_remainder (e, f);
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GC_BIGNUM (c);
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if (c == BIGNUM_OUT_OF_BAND) {
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return c;
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}
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if (k == 0) {
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/* no progress; do a Euclidean step */
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if (size_b == 0) {
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return bignum_trim (a);
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}
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e = bignum_trim (a);
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GC_BIGNUM(e);
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f = bignum_trim (b);
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GC_BIGNUM(f);
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c = bignum_remainder (e, f);
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GC_BIGNUM (c);
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if (c == BIGNUM_OUT_OF_BAND) {
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return c;
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}
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// copy 'b' to 'a'
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scan_a = BIGNUM_START_PTR (a);
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scan_b = BIGNUM_START_PTR (b);
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a_end = scan_a + size_a;
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b_end = scan_b + size_b;
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while (scan_b < b_end) *(scan_a++) = *(scan_b++);
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while (scan_a < a_end) *(scan_a++) = 0;
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size_a = size_b;
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// copy 'b' to 'a'
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scan_a = BIGNUM_START_PTR (a);
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scan_b = BIGNUM_START_PTR (b);
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a_end = scan_a + size_a;
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b_end = scan_b + size_b;
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while (scan_b < b_end) *(scan_a++) = *(scan_b++);
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while (scan_a < a_end) *(scan_a++) = 0;
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size_a = size_b;
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// copy 'c' to 'b'
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scan_b = BIGNUM_START_PTR (b);
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scan_c = BIGNUM_START_PTR (c);
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size_c = BIGNUM_LENGTH (c);
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c_end = scan_c + size_c;
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while (scan_c < c_end) *(scan_b++) = *(scan_c++);
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while (scan_b < b_end) *(scan_b++) = 0;
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size_b = size_c;
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// copy 'c' to 'b'
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scan_b = BIGNUM_START_PTR (b);
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scan_c = BIGNUM_START_PTR (c);
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size_c = BIGNUM_LENGTH (c);
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c_end = scan_c + size_c;
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while (scan_c < c_end) *(scan_b++) = *(scan_c++);
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while (scan_b < b_end) *(scan_b++) = 0;
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size_b = size_c;
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continue;
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}
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continue;
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}
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/*
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a, b = A*b - B*a, D*a - C*b if k is odd
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a, b = A*a - B*b, D*b - C*a if k is even
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*/
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scan_a = BIGNUM_START_PTR (a);
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scan_b = BIGNUM_START_PTR (b);
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scan_c = scan_a;
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scan_d = scan_b;
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a_end = scan_a + size_a;
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b_end = scan_b + size_b;
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s = 0;
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t = 0;
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if (k & 1) {
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while (scan_b < b_end) {
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s += (A * *scan_b) - (B * *scan_a);
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t += (D * *scan_a++) - (C * *scan_b++);
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*scan_c++ = (bignum_digit_type) (s & BIGNUM_DIGIT_MASK);
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*scan_d++ = (bignum_digit_type) (t & BIGNUM_DIGIT_MASK);
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s >>= BIGNUM_DIGIT_LENGTH;
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t >>= BIGNUM_DIGIT_LENGTH;
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}
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while (scan_a < a_end) {
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s -= (B * *scan_a);
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t += (D * *scan_a++);
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*scan_c++ = (bignum_digit_type) (s & BIGNUM_DIGIT_MASK);
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//*scan_d++ = (bignum_digit_type) (t & BIGNUM_DIGIT_MASK);
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s >>= BIGNUM_DIGIT_LENGTH;
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t >>= BIGNUM_DIGIT_LENGTH;
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}
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}
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else {
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while (scan_b < b_end) {
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s += (A * *scan_a) - (B * *scan_b);
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t += (D * *scan_b++) - (C * *scan_a++);
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*scan_c++ = (bignum_digit_type) (s & BIGNUM_DIGIT_MASK);
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*scan_d++ = (bignum_digit_type) (t & BIGNUM_DIGIT_MASK);
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s >>= BIGNUM_DIGIT_LENGTH;
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t >>= BIGNUM_DIGIT_LENGTH;
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}
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while (scan_a < a_end) {
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s += (A * *scan_a);
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t -= (C * *scan_a++);
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*scan_c++ = (bignum_digit_type) (s & BIGNUM_DIGIT_MASK);
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//*scan_d++ = (bignum_digit_type) (t & BIGNUM_DIGIT_MASK);
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s >>= BIGNUM_DIGIT_LENGTH;
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t >>= BIGNUM_DIGIT_LENGTH;
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}
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}
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BIGNUM_ASSERT (s == 0);
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BIGNUM_ASSERT (t == 0);
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/*
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a, b = A*b - B*a, D*a - C*b if k is odd
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a, b = A*a - B*b, D*b - C*a if k is even
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*/
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scan_a = BIGNUM_START_PTR (a);
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scan_b = BIGNUM_START_PTR (b);
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scan_c = scan_a;
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scan_d = scan_b;
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a_end = scan_a + size_a;
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b_end = scan_b + size_b;
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s = 0;
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t = 0;
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if (k & 1) {
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while (scan_b < b_end) {
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s += (A * *scan_b) - (B * *scan_a);
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t += (D * *scan_a++) - (C * *scan_b++);
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*scan_c++ = (bignum_digit_type) (s & BIGNUM_DIGIT_MASK);
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*scan_d++ = (bignum_digit_type) (t & BIGNUM_DIGIT_MASK);
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s >>= BIGNUM_DIGIT_LENGTH;
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t >>= BIGNUM_DIGIT_LENGTH;
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}
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while (scan_a < a_end) {
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s -= (B * *scan_a);
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t += (D * *scan_a++);
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*scan_c++ = (bignum_digit_type) (s & BIGNUM_DIGIT_MASK);
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//*scan_d++ = (bignum_digit_type) (t & BIGNUM_DIGIT_MASK);
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s >>= BIGNUM_DIGIT_LENGTH;
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t >>= BIGNUM_DIGIT_LENGTH;
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}
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}
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else {
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while (scan_b < b_end) {
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s += (A * *scan_a) - (B * *scan_b);
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t += (D * *scan_b++) - (C * *scan_a++);
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*scan_c++ = (bignum_digit_type) (s & BIGNUM_DIGIT_MASK);
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*scan_d++ = (bignum_digit_type) (t & BIGNUM_DIGIT_MASK);
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s >>= BIGNUM_DIGIT_LENGTH;
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t >>= BIGNUM_DIGIT_LENGTH;
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}
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while (scan_a < a_end) {
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s += (A * *scan_a);
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t -= (C * *scan_a++);
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*scan_c++ = (bignum_digit_type) (s & BIGNUM_DIGIT_MASK);
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//*scan_d++ = (bignum_digit_type) (t & BIGNUM_DIGIT_MASK);
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s >>= BIGNUM_DIGIT_LENGTH;
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t >>= BIGNUM_DIGIT_LENGTH;
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}
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}
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BIGNUM_ASSERT (s == 0);
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BIGNUM_ASSERT (t == 0);
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// update size_a and size_b to remove any zeros at end
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while (size_a > 0 && *(--scan_a) == 0) size_a--;
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while (size_b > 0 && *(--scan_b) == 0) size_b--;
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// update size_a and size_b to remove any zeros at end
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while (size_a > 0 && *(--scan_a) == 0) size_a--;
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while (size_b > 0 && *(--scan_b) == 0) size_b--;
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BIGNUM_ASSERT (size_a >= size_b);
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}
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BIGNUM_ASSERT (size_a >= size_b);
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}
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/* a fits into a fixnum, so b must too */
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fixnum xx = bignum_to_fixnum (a);
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fixnum yy = bignum_to_fixnum (b);
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fixnum tt;
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/* a fits into a fixnum, so b must too */
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fixnum xx = bignum_to_fixnum (a);
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fixnum yy = bignum_to_fixnum (b);
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fixnum tt;
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/* usual Euclidean algorithm for longs */
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while (yy != 0) {
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tt = yy;
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yy = xx % yy;
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xx = tt;
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}
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/* usual Euclidean algorithm for longs */
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while (yy != 0) {
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tt = yy;
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yy = xx % yy;
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xx = tt;
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}
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return fixnum_to_bignum (xx);
|
||||
return fixnum_to_bignum (xx);
|
||||
}
|
||||
#endif
|
||||
|
||||
|
|
|
|||
Loading…
Reference in New Issue