Initial commit

Makefile

@@ -1,8 +1,8 @@
 cat: cat.o
 	ld -o cat cat.o
 
-cat.o: cat.nasm
+cat.o: cat.s
-	nasm -f elf64 cat.nasm
+	nasm -g -f elf64 cat.s
 
 .PHONY: clean
 clean:

README.md

@@ -1,5 +1,3 @@
 # cat
-[![Build Status](https://ci.zander.im/job/asm-cat/badge/icon?style=flat&subject=Build)](https://ci.zander.im/job/asm-cat/)
 
-Posix compliant cat written in NASM Assembler for practice. This program
+Posix compliant cat written in NASM Assembler for practice.
-**ONLY** works on Linux.

cat.nasm

@@ -1,306 +0,0 @@
-;; -*- mode: asm; -*-
-%define SYS_open 0x2
-%define SYS_close 0x3
-%define SYS_write 0x1
-%define SYS_read 0x0
-%define SYS_lseek 0x8
-%define SYS_exit 0x3c
-
-%define O_RDONLY 0x0
-%define SEEK_SET 0x0
-%define FD_stderr 2
-%define FD_stdout 1
-%define FD_stdin 0
-
-%define BUFFER_SIZE 2048
-
-section .text
-global _start
-_start:
-    pop rax                     ; argc
-    pop QWORD [exec_name]       ; argv[0]
-
-check_arg_loop:
-    mov rdi,[rsp]               ; argv[i]
-    ; check for null
-    cmp rdi,0
-    je print_stdin_and_exit
-
-    ; check for flags
-    call check_flag
-    cmp rax,0
-    je print_files              ; no more flags
-
-    pop rdi                     ; remove argv[i] (a flag)
-    jmp check_arg_loop
-
-print_files:
-    mov rdi,[rsp]               ; argv[i]
-    cmp rdi,0
-    je print_files_end
-
-    ; check if argv[i] is '-'
-    mov rsi,dash_str
-    call streql
-    cmp rax,0
-    jne print_files_stdin
-
-    ; open file
-    mov rdi,[rsp]               ; argv[i]
-    call open_file
-
-    ; print file
-    mov rdi,rax
-    pop rsi                     ; argv[i]
-    call print_file
-
-    jmp print_files
-
-print_files_stdin:
-    pop rdi                     ; argv[i]
-    mov rdi,FD_stdin
-    mov rsi,stdin_name
-    call print_file
-
-    ; rewind stdin
-    mov rax,SYS_lseek
-    mov rdi,FD_stdin
-    mov rsi,0
-    mov rdx,SEEK_SET
-    syscall
-
-    jmp print_files
-
-print_files_end:
-    xor rdi,rdi
-    jmp exit
-
-open_file:                      ; int open_file(const char *path)
-    push rdi                    ; path
-
-    ; open file
-    mov rax,SYS_open
-    ; rdi already set
-    mov rsi,O_RDONLY
-    syscall
-
-    ; check return
-    cmp rax,0
-    jl open_error
-
-    pop rdi                     ; path
-    ret
-open_error:
-    call start_error
-
-    ; message
-    mov rax,SYS_write
-    mov rdi,FD_stderr
-    mov rsi,open_error_text
-    mov rdx,open_error_text_len
-    syscall
-
-    ; detail
-    mov rdi,[rsp]               ; path
-    call strlen
-
-    mov rdx,rax
-    mov rax,SYS_write
-    mov rdi,FD_stderr
-    pop rsi                     ; path
-    syscall
-
-    call end_error
-
-    mov rdi,1
-    jmp exit
-
-print_stdin_and_exit:
-    mov rdi,FD_stdin
-    mov rsi,stdin_name
-    call print_file
-    xor rdi,rdi
-    jmp exit
-
-print_file:                     ; void print_file(int fd, const char *name)
-    push rdi                    ; fd
-    push rsi                    ; name
-print_file_loop:
-    mov rax,SYS_read
-    mov rdi,[rsp + 8]           ; fd
-    mov rsi,read_buff
-    mov rdx,BUFFER_SIZE
-    syscall
-
-    ; check error
-    cmp rax,0
-    jl read_file_error
-
-    ; no more bytes
-    je print_file_end
-
-    ; print message
-    mov rdx,rax
-    mov rax,SYS_write
-    mov rdi,FD_stdout
-    mov rsi,read_buff
-    syscall
-
-    jmp print_file_loop
-
-print_file_end:
-    pop rsi                     ; name
-    pop rdi                     ; fd
-    ret
-
-read_file_error:
-    call start_error
-
-    ; message
-    mov rax,SYS_write
-    mov rdi,FD_stderr
-    mov rsi,read_error_text
-    mov rdx,read_error_text_len
-    syscall
-
-    ; detail
-    mov rdi,[rsp]               ; name
-    call strlen
-
-    mov rdx,rax
-    mov rax,SYS_write
-    mov rdi,FD_stderr
-    pop rsi                     ; name
-    syscall
-
-    call end_error
-
-    mov rdi,1
-    jmp exit
-
-;; check arg for -u, exit if unknown flag
-;; return 1 if found, 0 otherwise
-check_flag:                     ; bool check_arg(const char *arg)
-    xor rax,rax
-    ; check if arg[0] == '-'
-    cmp BYTE [rdi],'-'
-    jne check_flag_end
-
-    inc rdi
-    ; rax still set
-check_flag_loop:
-    ; check null byte
-    mov cl,[rdi]
-    cmp cl,0
-    je check_flag_end
-
-    ; check for u
-    cmp cl,'u'
-    jne check_flag_error
-
-    mov rax,1
-    inc rdi
-    jmp check_flag_loop
-check_flag_error:
-    push rdi                    ; arg + i
-    call start_error
-
-    ; message
-    mov rax,SYS_write
-    mov rdi,FD_stderr
-    mov rsi,arg_error_text
-    mov rdx,arg_error_text_len
-    syscall
-
-    ; character
-    mov rax,SYS_write
-    mov rdi,FD_stderr
-    pop rsi                     ; arg + i
-    mov rdx,1
-    syscall
-
-    call end_error
-
-    mov rdi,1
-    jmp exit
-check_flag_end:
-    ret
-
-;; print exec_name and a colon_space
-start_error:                    ; void start_error(void)
-    mov rdi,[exec_name]
-    call strlen
-    mov rdx,rax
-    mov rax,SYS_write
-    mov rdi,FD_stderr
-    mov rsi,[exec_name]
-    syscall
-
-    mov rax,SYS_write
-    mov rdi,FD_stderr
-    mov rsi,colon_space
-    mov rdx,colon_space_len
-    syscall
-    ret
-
-;; print newline
-end_error:                      ; void end_error(void)
-    mov rax,SYS_write
-    mov rdi,FD_stderr
-    mov rsi,newline_ptr
-    mov rdx,1
-    syscall
-    ret
-
-streql:                         ; bool streql(const char *s1, const char *s2)
-    ; check if both are zero
-    mov cl,[rdi]                ; s1[i]
-    or cl,[rsi]
-    jz streql_true
-
-    ; check if equal
-    mov cl,[rdi]
-    xor cl,[rsi]
-    jnz streql_false
-
-    inc rdi
-    inc rsi
-    jmp streql
-streql_true:
-    mov rax,1
-    ret
-streql_false:
-    xor rax,rax
-    ret
-
-exit:                           ; NORETURN void exit(int status)
-    mov rax,SYS_exit
-    syscall
-
-strlen:                         ; uint64 strlen(const char *str)
-    mov rax,rdi
-strlen_loop:
-    cmp BYTE [rax],0
-    je strlen_end
-    inc rax
-    jmp strlen_loop
-strlen_end:
-    sub rax,rdi
-    ret
-
-section .bss
-    exec_name resq 1
-    read_buff resb BUFFER_SIZE
-
-section .data
-    dash_str db "-",0x0
-    colon_space db ": "
-    colon_space_len equ $ - colon_space
-    newline_ptr db 0xA
-    stdin_name db "<stdin>",0x0
-    arg_error_text db "unknown flag: "
-    arg_error_text_len equ $ - arg_error_text
-    read_error_text db "read error: "
-    read_error_text_len equ $ - read_error_text
-    open_error_text db "could not open file for reading: "
-    open_error_text_len equ $ - open_error_text

cat.s

@@ -0,0 +1,310 @@
+%define SYS_open 0x2
+%define SYS_close 0x3
+%define SYS_write 0x1
+%define SYS_read 0x0
+%define SYS_lseek 0x8
+%define SYS_exit 0x3c
+%define SYS_fcntl 0x48
+
+%define O_RDONLY 0x0
+%define O_NONBLOCK 0x800
+%define F_GETFL 3
+%define F_SETFL 4
+%define SEEK_SET 0x0
+
+%define FD_stderr 2
+%define FD_stdout 1
+%define FD_stdin 0
+
+%define BUFFER_SIZE 2048
+
+section .text
+global _start
+_start:
+	pop rax 					; argc
+	pop QWORD [exec_name]		; argv[0]
+
+check_arg_loop:
+	mov rdi,[rsp] 				; argv[i]
+	; check for null
+	cmp rdi,0
+	je print_stdin_and_exit
+
+	; check for flags
+	call check_flag
+	cmp rax,0
+	je print_files 				; no more flags
+
+	pop rdi 					; remove argv[i] (a flag)
+	jmp check_arg_loop
+
+print_files:
+	mov rdi,[rsp] 				; argv[i]
+	cmp rdi,0
+	je print_files_end
+
+	; check if argv[i] is '-'
+	mov rsi,dash_str
+	call streql
+	cmp rax,0
+	jne print_files_stdin
+
+	; open file
+	mov rdi,[rsp] 				; argv[i]
+	call open_file
+
+	; print file
+	mov rdi,rax
+	pop rsi 					; argv[i]
+	call print_file
+
+	jmp print_files
+
+print_files_stdin:
+	pop rdi 					; argv[i]
+	mov rdi,FD_stdin
+	mov rsi,stdin_name
+	call print_file
+
+	; rewind stdin
+    mov rax,SYS_lseek
+	mov rdi,FD_stdin
+	mov rsi,0
+	mov rdx,SEEK_SET
+	syscall
+
+	jmp print_files
+
+print_files_end:
+	xor rdi,rdi
+	jmp exit
+
+open_file: 						; int open_file(const char *path)
+	push rdi 					; path
+
+	; open file
+	mov rax,SYS_open
+	; rdi already set
+	mov rsi,O_RDONLY
+	syscall
+
+	; check return
+	cmp rax,0
+	jl open_error
+
+	pop rdi 					; path
+	ret
+open_error:
+	call start_error
+
+	; message
+	mov rax,SYS_write
+	mov rdi,FD_stderr
+	mov rsi,open_error_text
+	mov rdx,open_error_text_len
+	syscall
+
+	; detail
+	mov rdi,[rsp] 				; path
+	call strlen
+
+	mov rdx,rax
+	mov rax,SYS_write
+	mov rdi,FD_stderr
+	pop rsi 					; path
+	syscall
+
+	call end_error
+
+	mov rdi,1
+	jmp exit
+
+print_stdin_and_exit:
+	mov rdi,FD_stdin
+	mov rsi,stdin_name
+	call print_file
+	xor rdi,rdi
+	jmp exit
+
+print_file: 					; void print_file(int fd, const char *name)
+	push rdi 					; fd
+	push rsi 					; name
+print_file_loop:
+	mov rax,SYS_read
+	mov rdi,[rsp + 8] 			; fd
+	mov rsi,read_buff
+	mov rdx,BUFFER_SIZE
+	syscall
+
+	; check error
+	cmp rax,0
+	jl read_file_error
+
+	; no more bytes
+	je print_file_end
+
+	; print message
+	mov rdx,rax
+	mov rax,SYS_write
+	mov rdi,FD_stdout
+	mov rsi,read_buff
+	syscall
+
+	jmp print_file_loop
+
+print_file_end:
+	pop rsi 					; name
+	pop rdi 					; fd
+	ret
+
+read_file_error:
+	call start_error
+
+	; message
+	mov rax,SYS_write
+	mov rdi,FD_stderr
+	mov rsi,read_error_text
+	mov rdx,read_error_text_len
+	syscall
+
+	; detail
+	mov rdi,[rsp]  				; name
+	call strlen
+
+	mov rdx,rax
+	mov rax,SYS_write
+	mov rdi,FD_stderr
+	pop rsi 					; name
+	syscall
+
+	call end_error
+
+	mov rdi,1
+	jmp exit
+
+;; check arg for -u, exit if unknown flag
+;; return 1 if found, 0 otherwise
+check_flag:						; bool check_arg(const char *arg)
+	xor rax,rax
+	; check if arg[0] == '-'
+	cmp BYTE [rdi],'-'
+	jne check_flag_end
+
+	inc rdi
+	; rax still set
+check_flag_loop:
+	; check null byte
+	mov cl,[rdi]
+	cmp cl,0
+	je check_flag_end
+
+	; check for u
+	cmp cl,'u'
+	jne check_flag_error
+
+	mov rax,1
+	inc rdi
+	jmp check_flag_loop
+check_flag_error:
+	push rdi 					; arg + i
+	call start_error
+
+	; message
+	mov rax,SYS_write
+	mov rdi,FD_stderr
+	mov rsi,arg_error_text
+	mov rdx,arg_error_text_len
+	syscall
+
+	; character
+	mov rax,SYS_write
+	mov rdi,FD_stderr
+	pop rsi 					; arg + i
+	mov rdx,1
+	syscall
+
+	call end_error
+
+	mov rdi,1
+	jmp exit
+check_flag_end:
+	ret
+
+;; print exec_name and a colon_space
+start_error: 					; void start_error(void)
+	mov rdi,[exec_name]
+	call strlen
+	mov rdx,rax
+	mov rax,SYS_write
+	mov rdi,FD_stderr
+	mov rsi,[exec_name]
+	syscall
+
+	mov rax,SYS_write
+	mov rdi,FD_stderr
+	mov rsi,colon_space
+	mov rdx,colon_space_len
+	syscall
+	ret
+
+;; print newline
+end_error: 						; void end_error(void)
+	mov rax,SYS_write
+	mov rdi,FD_stderr
+	mov rsi,newline_ptr
+	mov rdx,1
+	syscall
+	ret
+
+streql: 						; bool streql(const char *s1, const char *s2)
+	; check if both are zero
+	mov cl,[rdi] 				; s1[i]
+	or cl,[rsi]
+	jz streql_true
+
+	; check if equal
+	mov cl,[rdi]
+	xor cl,[rsi]
+	jnz streql_false
+
+	inc rdi
+	inc rsi
+	jmp streql
+streql_true:
+	mov rax,1
+	ret
+streql_false:
+	xor rax,rax
+	ret
+
+exit: 							; NORETURN void exit(int status)
+	mov rax,SYS_exit
+	syscall
+
+strlen: 						; uint64 strlen(const char *str)
+	mov rax,rdi
+strlen_loop:
+	cmp BYTE [rax],0
+	je strlen_end
+	inc rax
+	jmp strlen_loop
+strlen_end:
+	sub rax,rdi
+	ret
+
+section .bss
+	exec_name resq 1
+	read_buff resb BUFFER_SIZE
+
+section .data
+	dash_str db "-",0x0
+	colon_space db ": "
+	colon_space_len equ $ - colon_space
+	newline_ptr db 0xA
+	stdin_name db "<stdin>",0x0
+	arg_error_text db "unknown flag: "
+	arg_error_text_len equ $ - arg_error_text
+	read_error_text db "read error: "
+	read_error_text_len equ $ - read_error_text
+	open_error_text db "could not open file for reading: "
+	open_error_text_len equ $ - open_error_text