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Diffstat (limited to 'aoc-2025/day2.asm')
| -rw-r--r-- | aoc-2025/day2.asm | 324 |
1 files changed, 0 insertions, 324 deletions
diff --git a/aoc-2025/day2.asm b/aoc-2025/day2.asm deleted file mode 100644 index 987fbf9..0000000 --- a/aoc-2025/day2.asm +++ /dev/null @@ -1,324 +0,0 @@ -; Advent of Code 2025 – Day 2 - -bits 64 -default rel - -global _start - -%include "utils/io.asm" -%include "utils/parse.asm" - -section .data - input_path db "input/day2.txt", 0 - - label1 db "Part 1: ", 0 - label2 db "Part 2: ", 0 - -section .bss - buffer resb 4096 - line_buffer resb 65536 - line_len resd 1 - - sum1 resq 1 - sum2 resq 1 - -section .text - -_start: - mov rax, SYS_OPEN - mov rdi, input_path - mov rsi, O_RDONLY - xor rdx, rdx - syscall - - mov r12, rax ; file descriptor - mov dword [line_len], 0 - -read_loop: - mov rax, SYS_READ - mov rdi, r12 - mov rsi, buffer - mov rdx, 4096 - syscall - - cmp rax, 0 - jle eof - - mov rdi, buffer - mov rbp, rax - -scan_chunk: - cmp rbp, 0 - je read_loop - - mov al, [rdi] - - cmp al, 13 - je skip_cr - - cmp al, 10 - je end_line - - mov edx, [line_len] - cmp edx, 65535 - jae skip_store - mov [line_buffer+rdx], al - inc edx - mov [line_len], edx - -skip_store: - inc rdi - dec rbp - jmp scan_chunk - -skip_cr: - inc rdi - dec rbp - jmp scan_chunk - -end_line: - mov edx, [line_len] - mov byte [line_buffer+rdx], 0 - - cmp edx, 0 - je clear_line - - push rdi - mov rsi, line_buffer - call handle_line - pop rdi - -clear_line: - mov dword [line_len], 0 - inc rdi - dec rbp - jmp scan_chunk - -eof: - ; process final partial line if needed - mov edx, [line_len] - cmp edx, 0 - jle print_results - - mov byte [line_buffer+rdx], 0 - mov rsi, line_buffer - call handle_line - -print_results: - mov rcx, label1 - call print_string - mov rax, [sum1] - call print_int64 - call print_newline - - mov rcx, label2 - call print_string - mov rax, [sum2] - call print_int64 - call print_newline - - mov rax, SYS_CLOSE - mov rdi, r12 - syscall - - mov rax, SYS_EXIT - xor rdi, rdi - syscall - -; parse "A-B,C-D,..."l, RSI = pointer to line -; uses r13 = current ID, r14 = end of range -handle_line: -next_range: - ; parse start - call parse_u64 - mov r13, rax - - cmp byte [rsi], '-' - jne done_line - inc rsi - - ; parse end - call parse_u64 - mov r14, rax - -range_loop: - cmp r13, r14 - jg after_range - - ; Save RSI (line pointer) across the checks, - ; because number_to_string / check_invalid* use RSI - push rsi - - ; Part 1: exact AA - mov rax, r13 - call check_invalid1 - test rax, rax - jz .skip_p1 - add qword [sum1], r13 -.skip_p1: - ; Part 2: any repeating block >= 2 - mov rax, r13 - call check_invalid2 - test rax, rax - jz .skip_p2 - add qword [sum2], r13 -.skip_p2: - pop rsi ; restore line pointer - - inc r13 - jmp range_loop - -after_range: - cmp byte [rsi], ',' - jne done_line - inc rsi - jmp next_range - -done_line: - ret - -; number_to_string: convert RAX to decimal ASCII, MSB-first -; Output: -; RSI = pointer to first digit -; ECX = length -number_to_string: - mov rdi, number_buffer+31 - mov byte [rdi], 0 ; terminator (for convenience) - dec rdi - - cmp rax, 0 - jne .conv - - ; handle zero - mov byte [rdi], '0' - mov rsi, rdi - mov ecx, 1 - ret - -.conv: - mov rbx, 10 -.next_digit: - xor rdx, rdx - div rbx ; RAX = quotient, RDX = remainder - add dl, '0' - mov [rdi], dl - dec rdi - test rax, rax - jnz .next_digit - - inc rdi ; now RDI points to first digit - mov rsi, rdi - mov rdx, number_buffer+31 - sub rdx, rsi ; RDX = length - mov ecx, edx - ret - -; check_invalid1: "AA" pattern -; RAX = number -; Returns RAX = 1 if digits == A A, else 0 -check_invalid1: - push rbx - push rdx - - call number_to_string ; RSI=string, ECX=len - mov eax, ecx ; EAX = len - - cmp eax, 2 - jl .no1 - - test eax, 1 - jnz .no1 ; odd length => cannot be AA - - shr eax, 1 ; half = len/2 - mov r8d, eax ; half - xor r9d, r9d ; i = 0 - -.loop1: - cmp r9d, r8d - jge .yes1 - - ; s[i] - mov rdx, r9 - movzx eax, byte [rsi + rdx] - - ; s[i+half] - mov rdx, r9 - add rdx, r8 - movzx ebx, byte [rsi + rdx] - - cmp eax, ebx - jne .no1 - - inc r9d - jmp .loop1 - -.yes1: - mov rax, 1 - jmp .ret1 - -.no1: - xor rax, rax - -.ret1: - pop rdx - pop rbx - ret - -; check_invalid2: any repeating block >= 2 -; RAX = number -; Returns RAX = 1 if string is some A repeated k>=2 times -check_invalid2: - push rbx - push rdx - - call number_to_string ; RSI=string, ECX=len - mov r11d, ecx ; n = length - - cmp r11d, 2 - jb .no2 - - mov r8d, 1 ; m = 1 (candidate period) -.outer: - cmp r8d, r11d - jge .no2 - - ; if n % m != 0 => cannot tile - mov eax, r11d - xor edx, edx - div r8d ; EAX=q, EDX=r - test edx, edx - jnz .next_m - - mov r9d, r11d - sub r9d, r8d ; limit = n - m - xor r10d, r10d ; i = 0 -.inner: - cmp r10d, r9d - jge .yes2 ; all positions checked - - ; s[i] - mov rdx, r10 - movzx eax, byte [rsi + rdx] - - ; s[i+m] - mov rdx, r10 - add rdx, r8 - movzx ebx, byte [rsi + rdx] - - cmp eax, ebx - jne .next_m - - inc r10d - jmp .inner -.yes2: - mov rax, 1 - jmp .ret2 -.next_m: - inc r8d - jmp .outer -.no2: - xor rax, rax -.ret2: - pop rdx - pop rbx - ret |