Primer dia resolt del Advent of Code 2025

.gitignore

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+out_a64

aoc25_1/Makefile

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+build:
+	gcc -g src/aoc25.c src/*.s -o out_a64

aoc25_1/src/aoc25.c

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+#include <stdio.h>
+#include <string.h>
+
+extern int left(int a, int b);
+extern int right(int a, int b);
+extern int count(int a, int b);
+
+int main(void) {
+    int dial = 50;
+    int rotation;
+    char direction[2];
+    int password = 0;
+
+    FILE *fptr = fopen("aoc25_1.txt", "r");
+
+    if (fptr == NULL) {
+        printf("Error, puzzle input aoc25_1.txt not found\n");
+        return (1);
+    }
+
+    printf("DIAL starts at %d\n", dial);
+
+    while (fscanf(fptr, "%s %d", direction, &rotation) == 2) {
+        printf("DIRECTION %s ROTATION %d\n", direction, rotation);
+
+        if (strcmp(direction, "L") == 0) {
+            dial = left(dial, rotation);
+            printf("DIAL is now %d\n", dial);
+        }
+
+        if (strcmp(direction, "R") == 0) {
+            dial = right(dial, rotation);
+            printf("DIAL is now %d\n", dial);
+        }
+
+        password = count(password, dial);
+        printf("PASSWORD is now %d\n", password);
+    }
+
+    fclose(fptr);
+
+    return (0);
+}

aoc25_1/src/count.s

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+    .global    count
+    .type      count, "function"
+    .p2align   4
+
+count:
+    cmp w1, #0
+    b.eq count1
+    b finish
+count1:
+    add w0, w0, #1
+finish:
+    ret

aoc25_1/src/left.s

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+    .global    left
+    .type      left, "function"
+    .p2align   4
+
+left:
+    subs w0, w0, #1
+    b.lt loop99
+    b left1
+left1:
+    subs w1, w1, #1
+    b.eq finish
+    b left
+loop99:
+    mov w0, #99
+    b left1
+finish:
+    ret

aoc25_1/src/right.s

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+    .global    right
+    .type      right, "function"
+    .p2align   4
+
+right:
+    adds w0, w0, #1
+    cmp w0, #99
+    b.gt loop0
+    b right1
+right1:
+    subs w1, w1, #1
+    b.eq finish
+    b right
+loop0:
+    mov w0, #0
+    b right1
+finish:
+    ret