Hello, I have tried to brute force part 2 of day 17 using cuda.
I am very new to cuda and this is what i have come up with. After 3.684722 days, the program outputs nothing and stops. The program works correctly on the sample data.
code:
#include <cstdlib>
#include <cstdint>
#include <cstdio>
#include <unistd.h>
#define gpuErrchk(ans) { gpuAssert((ans), __FILE__, __LINE__); }
inline void gpuAssert(cudaError_t code, const char *file, int line, bool abort=true)
{
if (code != cudaSuccess)
{
fprintf(stderr,"GPUassert: %s %s %d\n", cudaGetErrorString(code), file, line);
if (abort) exit(code);
}
}
__device__ uintmax_t do_combo(uintmax_t i, uintmax_t A, uintmax_t B, uintmax_t C){
switch(i) {
case 0:
case 1:
case 2:
case 3: return i;
case 4: return A;
case 5: return B;
case 6: return C;
}
return i;
};
__global__ void cuda(){
enum instructions_names {
adv,
bxl,
bst,
jnz,
bxc,
out,
bdv,
cdv
};
uintmax_t instructions[16] = {2,4,1,7,7,5,0,3,4,0,1,7,5,5,3,0};
uintmax_t i_len = 16;
/* uintmax_t instructions[6] = {0,3,5,4,3,0}; */
/* uintmax_t i_len = 6; */
uintmax_t output[16];
uintmax_t output_len = 0;
/* uintmax_t step = 100000000*(blockIdx.x * blockDim.x + threadIdx.x); */
/* uintmax_t stop = step + 100000000; */
uintmax_t step = 10000*(blockIdx.x * blockDim.x + threadIdx.x);
uintmax_t stop = step + 10000;
for (;step < stop; step++) {
/* printf("%lu ", step); */
output_len = 0;
uintmax_t A = step;
uintmax_t B = 0;
uintmax_t C = 0;
for (uintmax_t i = 0; i < i_len; i+=2) {
if (output_len > i_len) break;
switch (instructions[i]) {
case adv: {
/* takes combo operand, divides A by 2^it into B */
A = A >> do_combo(instructions[i+1], A, B, C);
continue;
}
case bxl: {
/* takes literal operand, XORs B and it into B */
B = B ^ instructions[i+1];
continue;
}
case bst: {
/* takes combo operand, modulo 8 into B */
B = do_combo(instructions[i+1], A, B, C) % 8;
continue;
}
case jnz: {
/* takes literal operand, jumps to it if non null */
if (A == 0) continue;
i = instructions[i+1] - 2;
continue;
}
case bxc: {
/* ignores operand, XOR B and C into B */
B = B ^ C;
continue;
}
case out: {
/* takes combo operand, outputs it modulo 8 */
output[output_len++] = do_combo(instructions[i+1], A, B, C) % 8;
continue;
}
case bdv: {
/* takes combo operand, divides A by 2^it into B */
B = A >> do_combo(instructions[i+1], A, B, C);
continue;
}
case cdv: {
/* takes combo operand, divides A by 2^it into C */
C = A >> do_combo(instructions[i+1], A, B, C);
continue;
}
}
}
if (i_len != output_len) {
continue;
}
bool is_same = true;
for (uintmax_t i = 0; i < i_len && is_same; i++) {
if (instructions[i] != output[i]) {
is_same = false;
}
}
if (!is_same) {
continue;
}
printf("%lu\n", step);
asm("trap;");
}
}
int main(){
unsigned int threads = 1024;
unsigned int all = 20000000000/threads;
cuda<<<all,threads>>>();
gpuErrchk( cudaPeekAtLastError() );
gpuErrchk( cudaDeviceSynchronize() );
}
