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#include <stdio.h> | |
#include <stdint.h> | |
#define ADD_LOBIT(a, b, c) ((a)^(b)^(c)) | |
#define ADD_CARRY(a, b, c) ((a&b)|(b&c)|(c&a)) | |
#define ADD_ROUND(i) \ | |
c|=ADD_LOBIT((a>>(i))&1,(b>>(i))&1,carry)<<(i); \ | |
carry=ADD_CARRY((a>>(i))&1,(b>>(i))&1,carry); | |
#define MUL_ROUND(i) \ | |
c <<= 1; \ | |
if ((b<<(i))&(1L<<63)) c = add(c, a); | |
#define LOOP2(c,i) c(i) c(i|1) | |
#define LOOP4(c,i) LOOP2(c,i) LOOP2(c,i|2) | |
#define LOOP8(c,i) LOOP4(c,i) LOOP4(c,i|4) | |
#define LOOP16(c,i) LOOP8(c,i) LOOP8(c,i|8) | |
#define LOOP32(c,i) LOOP16(c,i) LOOP16(c,i|16) | |
#define LOOP64(c,i) LOOP32(c,i) LOOP32(c,i|32) | |
uint64_t add(uint64_t a, uint64_t b) { | |
uint64_t c = 0, carry = 0; | |
LOOP64(ADD_ROUND, 0); | |
return c; | |
} | |
uint64_t mul(uint64_t a, uint64_t b) { | |
uint64_t c = 0; | |
LOOP64(MUL_ROUND, 0); | |
return c; | |
} | |
int main() { | |
uint64_t a = 0xdeadbeef1337; | |
uint64_t b = 0xbadf00d31337; | |
printf("0x%lx + 0x%lx => 0x%lx\n", a, b, add(a, b)); | |
printf("0x%lx * 0x%lx => 0x%lx\n", a, b, mul(a, b)); | |
} |
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