diff options
Diffstat (limited to 'src/Day3.asm')
| -rw-r--r-- | src/Day3.asm | 301 |
1 files changed, 0 insertions, 301 deletions
diff --git a/src/Day3.asm b/src/Day3.asm deleted file mode 100644 index e547475..0000000 --- a/src/Day3.asm +++ /dev/null @@ -1,301 +0,0 @@ -; Advent of Code 2025 - Day 3 - -bits 64 -default rel - -global _start - -%define SYS_EXIT 60 -%define SYS_READ 0 -%define SYS_WRITE 1 -%define SYS_OPEN 2 -%define SYS_CLOSE 3 - -%define O_RDONLY 0 -%define STDOUT 1 - -section .data - inputPath db "input/day3.txt", 0 - - newline db 10 - - label1 db "Part 1: ", 0 - label2 db "Part 2: ", 0 - -section .bss - buffer resb 4096 - lineBuffer resb 65536 - lineLen resd 1 - - sum1 resq 1 - sum2 resq 1 - - workDigits resb 64 ; stack for greedy subsequence - numberBuffer resb 32 ; for printing - -section .text - -_start: - mov rax, SYS_OPEN - mov rdi, inputPath - mov rsi, O_RDONLY - xor rdx, rdx - syscall - - mov r12, rax ; fd - mov dword [lineLen], 0 - -ReadLoop: - 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 - -ScanChunk: - cmp rbp, 0 - je ReadLoop - - mov al, [rdi] - - cmp al, 13 - je SkipCR - - cmp al, 10 - je EndLine - - mov edx, [lineLen] - cmp edx, 65535 - jae SkipStore - mov [lineBuffer+rdx], al - inc edx - mov [lineLen], edx - -SkipStore: - inc rdi - dec rbp - jmp ScanChunk - -SkipCR: - inc rdi - dec rbp - jmp ScanChunk - -EndLine: - mov edx, [lineLen] - mov byte [lineBuffer+edx], 0 - - cmp edx, 0 - je ClearLine - - push rdi - mov rsi, lineBuffer - call HandleLine - pop rdi - -ClearLine: - mov dword [lineLen], 0 - inc rdi - dec rbp - jmp ScanChunk - -EOF: - ; possible last partial line - mov edx, [lineLen] - cmp edx, 0 - jle PrintResults - - mov byte [lineBuffer+edx], 0 - mov rsi, lineBuffer - call HandleLine - -PrintResults: - mov rcx, label1 - call PrintString - mov rax, [sum1] - call PrintInt64 - call Newline - - mov rcx, label2 - call PrintString - mov rax, [sum2] - call PrintInt64 - call Newline - - mov rax, SYS_CLOSE - mov rdi, r12 - syscall - - mov rax, SYS_EXIT - xor rdi, rdi - syscall - -HandleLine: - mov rdi, rsi - xor ecx, ecx ; ECX = 0 -.lengthLoop: - mov al, [rdi+rcx] - cmp al, 0 - je .lengthDone - inc ecx - jmp .lengthLoop -.lengthDone: - mov r15d, ecx ; r15d = n - - ; part 1: k = 2 - mov ecx, r15d ; ECX = n - mov edi, 2 ; K = 2 - call GetMaxForK ; RAX = best 2-digit value - add qword [sum1], rax - - ; part 2: k = 12, only if n >= 12 - cmp r15d, 12 - jl .skipPart2 - - mov ecx, r15d - mov edi, 12 - call GetMaxForK ; RAX = best 12-digit value - add qword [sum2], rax - -.skipPart2: - ret - -; Greedy lexicographically largest subsequence of length K -; -; Input: -; RSI -> digits string -; ECX = n (length) -; EDI = k -; Output: -; RAX = numeric value of chosen k digits -; Clobbers: R8..R11, EAX, EDX -GetMaxForK: - ; dropsRemaining = n - k - mov eax, ecx - sub eax, edi - mov r8d, eax ; r8d = drops - - xor r9d, r9d ; r9d = stackSize - xor r10d, r10d ; r10d = i - -.loop: - cmp r10d, ecx - jge .after_input - - ; current digit in AL - mov r11, r10 - mov al, [rsi + r11] - -.pop: - cmp r9d, 0 - jle .push - cmp r8d, 0 - jle .push - - mov edx, r9d - dec edx - mov r11d, edx - mov bl, [workDigits + r11] - - cmp bl, al - jge .push - - dec r9d - dec r8d - jmp .pop -.push: - mov r11d, r9d - mov [workDigits + r11], al - inc r9d - inc r10d - jmp .loop - -.after_input: - ; trim if stackSize > k -.trim: - cmp r9d, edi - jle .convert - dec r9d - jmp .trim -.convert: - xor rax, rax - xor r11d, r11d -.convertLoop: - cmp r11d, edi - jge .done - - mov rdx, r11 - mov dl, [workDigits + rdx] - sub dl, '0' - movzx rdx, dl - - imul rax, rax, 10 - add rax, rdx - - inc r11d - jmp .convertLoop -.done: - ret - -Newline: - mov rax, SYS_WRITE - mov rdi, STDOUT - mov rsi, newline - mov rdx, 1 - syscall - ret - -PrintInt64: - mov rdi, numberBuffer+31 - mov byte [rdi], 0 - dec rdi - - cmp rax, 0 - jne .conv - - mov byte [rdi], '0' - jmp .done -.conv: - mov rbx, 10 -.next: - xor rdx, rdx - div rbx - add dl, '0' - mov [rdi], dl - dec rdi - test rax, rax - jnz .next - - inc rdi -.done: - mov rax, SYS_WRITE - mov rsi, rdi - mov rdi, STDOUT - mov rdx, numberBuffer+31 - sub rdx, rsi - syscall - ret - -PrintString: - push rcx - push rdx - mov rdx, 0 -.length: - cmp byte [rcx+rdx], 0 - je .submit - inc rdx - jmp .length -.submit: - mov rax, SYS_WRITE - mov rdi, STDOUT - mov rsi, rcx - syscall - pop rdx - pop rcx - ret |