From 600bef43c9d67dfcd6a884306c19121bec0235a7 Mon Sep 17 00:00:00 2001 From: garhve Date: Wed, 14 Dec 2022 19:55:37 +0800 Subject: remove a.out --- nasm/triangle.asm | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) create mode 100644 nasm/triangle.asm (limited to 'nasm/triangle.asm') diff --git a/nasm/triangle.asm b/nasm/triangle.asm new file mode 100644 index 0000000..a7a443d --- /dev/null +++ b/nasm/triangle.asm @@ -0,0 +1,33 @@ + global _start + section .text +_start: + mov rdx, output ; rdx holds next byte's address to write + mov r8, 1 ; initial line length + mov r9, 0 ; number of stars written to line so far +_line: + mov byte [rdx], '*' ; write single star to memory at given address in rdx + inc rdx ; increase rdx to next call to write + inc r9 ; count number so far on line + cmp r9, r8 ; compare if stars number exceed line length + jne _line ; loop if not yet exceed +_linedone: + mov byte [rdx], 10 ; newline + inc rdx ; move rdx to next memory address + inc r8 ; increase line length + mov r9, 0 ; reset stars number for new line + cmp r8, maxlines ; compare if reached max line + jng _line ; loop newline +_done: + mov rax, 1 ; invoke system call for write + mov rdi, 1 ; file handler 1 is stdout + mov rsi, output ; address of string to output + mov rdx, datasize ; number of bytes + syscall ; invoke OS to write + mov rax, 60 ; invoke system call for exit + xor rdi, rdi ; exit code 0 + syscall ; invoke OS to exit + + section .bss +maxlines: equ 8 +datasize: equ 44 +output: resb datasize -- cgit v1.2.3-70-g09d2