| 1 | # Bignum multiplication and division
|
| 2 |
|
| 3 |
|
| 4 |
|
| 5 |
|
| 6 |
|
| 7 | mmul = (a, b) ->
|
| 8 | return a.multiply b
|
| 9 |
|
| 10 |
|
| 11 | mdiv = (a, b) ->
|
| 12 | return a.divide b
|
| 13 |
|
| 14 | # a = a + b
|
| 15 |
|
| 16 | ###
|
| 17 | static void
|
| 18 | addf(unsigned int *a, unsigned int *b, int len)
|
| 19 | {
|
| 20 | int i
|
| 21 | long long t = 0; # can be signed or unsigned
|
| 22 | for (i = 0; i < len; i++) {
|
| 23 | t += (long long) a[i] + b[i]
|
| 24 | a[i] = (unsigned int) t
|
| 25 | t >>= 32
|
| 26 | }
|
| 27 | }
|
| 28 |
|
| 29 | // a = a - b
|
| 30 |
|
| 31 | static void
|
| 32 | subf(unsigned int *a, unsigned int *b, int len)
|
| 33 | {
|
| 34 | int i
|
| 35 | long long t = 0; # must be signed
|
| 36 | for (i = 0; i < len; i++) {
|
| 37 | t += (long long) a[i] - b[i]
|
| 38 | a[i] = (unsigned int) t
|
| 39 | t >>= 32
|
| 40 | }
|
| 41 | }
|
| 42 |
|
| 43 | // a = b * c
|
| 44 |
|
| 45 | // 0xffffffff + 0xffffffff * 0xffffffff == 0xffffffff00000000
|
| 46 |
|
| 47 | static void
|
| 48 | mulf(unsigned int *a, unsigned int *b, int len, unsigned int c)
|
| 49 | {
|
| 50 | int i
|
| 51 | unsigned long long t = 0; # must be unsigned
|
| 52 | for (i = 0; i < len; i++) {
|
| 53 | t += (unsigned long long) b[i] * c
|
| 54 | a[i] = (unsigned int) t
|
| 55 | t >>= 32
|
| 56 | }
|
| 57 | a[i] = (unsigned int) t
|
| 58 | }
|
| 59 | ###
|
| 60 |
|
| 61 | mmod = (a,b) ->
|
| 62 | return a.mod b
|
| 63 |
|
| 64 | # return both quotient and remainder of a/b
|
| 65 | # we'd have this method as divmod(number)
|
| 66 | # but obviously doesn't change the passed parameters
|
| 67 |
|
| 68 | mdivrem = (a,b) ->
|
| 69 | toReturn = a.divmod b
|
| 70 | return [toReturn.quotient, toReturn.remainder]
|
| 71 |
|
| 72 | #if SELFTEST
|
| 73 |
|
| 74 | # small integer tests
|
| 75 |
|