163 lines
4.6 KiB
C
163 lines
4.6 KiB
C
/* aoc-c.c: Advent of Code 2019, day 5 parts 1 & 2
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*
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* Copyright (C) 2021 Bruno Raoult ("br")
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* Licensed under the GNU General Public License v3.0 or later.
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* Some rights reserved. See COPYING.
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*
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* You should have received a copy of the GNU General Public License along with this
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* program. If not, see <https://www.gnu.org/licenses/gpl-3.0-standalone.html>.
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*
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* SPDX-License-Identifier: GPL-3.0-or-later <https://spdx.org/licenses/GPL-3.0-or-later.html>
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <string.h>
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#include "br.h"
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#include "bits.h"
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#include "debug.h"
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typedef enum {
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ADD = 1, MUL = 2,
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INP = 3, OUT = 4,
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JMP_T = 5, JMP_F = 6,
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SET_LT = 7, SET_EQ = 8,
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HLT = 99
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} opcode_t;
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/**
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* ops - array of op-codes, mnemo, and number of parameters
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* @op: An integer, the opcode
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* @nargs: Opcode number of parameters (unused)
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* @jump: Next instruction (usually @nargs + 1)
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* @mnemo: Opcode mnemo (unused, for debug)
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*/
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typedef struct {
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int op;
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u8 nargs;
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u8 jump;
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char *mnemo;
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} ops_t;
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#define MAXOPS 1024
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typedef struct {
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int length; /* total program length */
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int cur; /* current position */
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int mem [MAXOPS]; /* should really be dynamic */
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} program_t;
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static ops_t ops[] = {
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[ADD] = { ADD, 3, 4, __stringify(ADD) },
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[MUL] = { MUL, 3, 4, __stringify(MUL) },
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[INP] = { INP, 1, 2, __stringify(INP) },
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[OUT] = { OUT, 1, 2, __stringify(OUT) },
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[JMP_T] = { JMP_T, 2, 3, __stringify(JMP_T) },
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[JMP_F] = { JMP_F, 2, 3, __stringify(JMP_F) },
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[SET_LT] = { SET_LT, 3, 4, __stringify({SET_LT) },
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[SET_EQ] = { SET_EQ, 3, 4, __stringify(SET_EQ) },
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[HLT] = { HLT, 0, 1, __stringify(HLT) }
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};
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static int _flag_pow10[] = {1, 100, 1000, 10000};
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#define OP(p, n) ((p->mem[n]) % 100)
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#define ISDIRECT(p, n, i) ((((p->mem[n]) / _flag_pow10[i]) % 10))
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#define DIRECT(p, i) ((p)->mem[i])
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#define INDIRECT(p, i) (DIRECT(p, DIRECT(p, i)))
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#define peek(p, n, i) (ISDIRECT(p, n, i)? DIRECT(p, n + i): INDIRECT(p, n + i))
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#define poke(p, n, i, val) do { \
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INDIRECT(p, n + i) = val; } \
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while (0)
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static int run(program_t *p, int in)
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{
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int out = -1;
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while (1) {
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int op = OP(p, p->cur), cur = p->cur;
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if (!(ops[op].op)) {
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fprintf(stderr, "PANIC: illegal instruction %d at %d.\n", op, p->cur);
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return -1;
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}
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switch (op) {
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case ADD:
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poke(p, p->cur, 3, peek(p, p->cur, 1) + peek(p, p->cur, 2));
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break;
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case MUL:
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poke(p, p->cur, 3, peek(p, p->cur, 1) * peek(p, p->cur, 2));
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break;
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case INP:
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poke(p, p->cur, 1, in);
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break;
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case OUT:
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out = peek(p, p->cur, 1);
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break;
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case JMP_T:
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if (peek(p, p->cur, 1))
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p->cur = peek(p, p->cur, 2);
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break;
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case JMP_F:
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if (!peek(p, p->cur, 1))
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p->cur = peek(p, p->cur, 2);
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break;
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case SET_LT:
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poke(p, p->cur, 3, peek(p, p->cur, 1) < peek(p, p->cur, 2) ? 1: 0);
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break;
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case SET_EQ:
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poke(p, p->cur, 3, peek(p, p->cur, 1) == peek(p, p->cur, 2) ? 1: 0);
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break;
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case HLT:
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return out;
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}
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if (p->cur == cur)
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p->cur += ops[op].jump;
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}
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}
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static void parse(program_t *prog)
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{
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while (scanf("%d%*c", &prog->mem[prog->length++]) > 0)
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;
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}
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static int usage(char *prg)
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{
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fprintf(stderr, "Usage: %s [-d debug_level] [-p part] [-i input]\n", prg);
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return 1;
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}
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int main(int ac, char **av)
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{
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int opt, part = 1, in = -1;
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program_t p = { 0 };
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while ((opt = getopt(ac, av, "d:p:i:")) != -1) {
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switch (opt) {
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case 'd':
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debug_level_set(atoi(optarg));
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break;
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case 'i':
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in = atoi(optarg);
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break;
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case 'p': /* 1 or 2 */
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part = atoi(optarg);
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if (part < 1 || part > 2)
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return usage(*av);
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break;
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default:
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return usage(*av);
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}
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}
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if (optind < ac)
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return usage(*av);
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if (in == -1)
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in = part == 1? 1: 5;
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parse(&p);
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printf("%s : res=%d\n", *av, run(&p, in));
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exit (0);
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}
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