68 lines
1.1 KiB
C
68 lines
1.1 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 += 1;
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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 -= 1;
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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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