diff options
Diffstat (limited to '2022/01/part2.asm')
| -rw-r--r-- | 2022/01/part2.asm | 82 |
1 files changed, 82 insertions, 0 deletions
diff --git a/2022/01/part2.asm b/2022/01/part2.asm new file mode 100644 index 0000000..6fed668 --- /dev/null +++ b/2022/01/part2.asm @@ -0,0 +1,82 @@ +%include "unistd.asm" +%include "utils.asm" + +stdout equ 1 + +global _start + +section .text +_start: + mov rcx, [rsp] ; Get number of arguments + mov rdi, [rsp + rcx * 8] ; Get last argument + + mov rax, SYS_access ; Check if file exists and is readable + mov esi, R_OK + syscall + test rax, rax + jnz .exit_err + + mov rax, SYS_open + xor esi, esi + xor edx, edx + syscall + + mov r8d, eax ; Move fd into r8 + mov rax, SYS_mmap + xor edi, edi ; Let the kernel choose the address + mov rsi, 12288 + mov rdx, PROT_READ + mov r10d, MAP_PRIVATE + xor r9d, r9d + syscall + + cmp rax, -1 ; Exit on error + je .exit_err + + xor r12d, r12d ; current count for elf + xor r13d, r13d ; Max # cal for one elf + xor r14d, r14d ; 2nd max # cal for one elf + xor r15d, r15d ; 3rd max # cal for one elf + mov rdi, rax +.loop: + cmp byte [rdi], 0 + je .exit + call atoi + add r12d, eax + cmp byte [rdi], 0 + inc rdi + je .exit + cmp byte [rdi], `\n` + je .next_elf + jmp .loop + +.next_elf: + cmp r15d, r12d + cmovl r15d, r12d + xor r12d, r12d + cmp r14d, r15d + jge .cmp_top_2 + xchg r14d, r15d +.cmp_top_2: + cmp r13d, r14d + jge .done + xchg r13d, r14d +.done: + add rdi, 1 + jmp .loop + +.exit: + mov edi, stdout + mov esi, r13d + add esi, r14d + add esi, r15d + call write_ulong + + mov rax, SYS_exit + xor edi, edi + syscall + +.exit_err: + mov rax, SYS_exit + mov edi, 1 + syscall |