diff options
Diffstat (limited to 'nasm')
| -rwxr-xr-x | nasm/helloworld.asm | 31 | ||||
| -rw-r--r-- | nasm/holamundo.asm | 10 | ||||
| -rw-r--r-- | nasm/triangle.asm | 33 |
3 files changed, 57 insertions, 17 deletions
diff --git a/nasm/helloworld.asm b/nasm/helloworld.asm index 3016f58..48755fb 100755 --- a/nasm/helloworld.asm +++ b/nasm/helloworld.asm @@ -1,17 +1,14 @@ -SECTION .data -msg db "Hello World!", 0Ah ; - -SECTION .text -global _start - -_start: - - mov edx, 13 ; number of bytes to write - mov ecx, msg ; move memory address of 'msg' to ecx - mov ebx, 1 ; write to the file STDOUT - mov eax, 4 ; invoke SYS_WRITE (kernel opcode 4) - int 80h - - mov ebx, 0 ; - mov eax, 1 ; - int 80h + global _start + + section .text +_start: mov rax, 1 ; system call for write + mov rdi, 1 ; file handle 1 is stdout + mov rsi, msg ; address of string to output + mov rdx, 13 ; number of bytes + syscall ; invoke operating system to do the write + mov rax, 60 ; system call for exit + xor rdi, rdi ; exit code 0; + syscall ; invoke operating system to exit + + section .data +msg db "hello, world",10 ; note the new line at end diff --git a/nasm/holamundo.asm b/nasm/holamundo.asm new file mode 100644 index 0000000..c7d3950 --- /dev/null +++ b/nasm/holamundo.asm @@ -0,0 +1,10 @@ + global main + extern puts + section .text +main: + mov rdi, message + call puts + ret + +message: + db "hola, mundo", 0 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 |