99 lines
1.8 KiB
C
99 lines
1.8 KiB
C
#include "silly.h"
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silly silly_zeros() {
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silly s;
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s.sign = 0;
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s.before = 0;
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s.after = 0;
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return s;
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}
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silly silly_add(silly x, silly y) {
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if (x.sign ^ y.sign) {
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if (x.sign) {
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x.sign = 0;
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return silly_sub(y, x);
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}
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y.sign = 0;
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return silly_sub(x, y);
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}
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silly z = silly_zeros();
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z.sign = x.sign | y.sign;
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// Note: Overflow
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z.before = x.before + y.before;
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z.after = x.after + y.after;
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if (z.after < x.after && z.after < y.after) z.before++;
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return z;
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}
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silly silly_sub(silly x, silly y) {
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if (y.sign) {
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y.sign = 0;
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return silly_add(x, y);
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}
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if (x.sign) {
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x.sign = 0;
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x = silly_add(x, y);
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x.sign = 1;
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return x;
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}
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silly z = silly_zeros();
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// Note: Underflow
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z.before = x.before - y.before;
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if (z.before > x.before) {
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z.sign = 1;
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z.before = 0xffffffff - z.before + 1;
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}
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z.after = x.after - y.after;
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if (z.after > x.after) z.before--;
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return z;
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}
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silly silly_mul(silly x, silly y) {
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silly z = silly_zeros();
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z.sign = x.sign ^ y.sign;
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uint64_t t0 = (x.before * y.after);
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uint64_t t1 = (y.before * x.after);
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z.before = x.before * y.before + (t0>>32) + (t1>>32);
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uint32_t t0b = t0&0xffffffff;
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uint32_t t1b = t1&0xffffffff;
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uint32_t tsum = t0b + t1b;
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if (tsum < t0b || tsum < t1b) z.before++;
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z.after = x.after * y.after + tsum;
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if (z.after < tsum) z.before++;
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return z;
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}
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char* silly_to_string(silly s) {
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char* res = malloc(23);
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snprintf(res, 23, "%s%010d.%010d", s.sign? "-" : "+", s.before, s.after);
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return res;
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}
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double silly_to_double(silly s) {
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return ((double)s.before + ((double)s.after)/(double)0xffffffff) * (s.sign ? -1 : 1);
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}
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silly make_silly(short sign, int before, int after) {
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silly s;
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s.sign = sign;
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s.before = before;
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s.after = after;
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return s;
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}
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