////////////////////////////////////////////////////////////////////////////////
// nop
////////////////////////////////////////////////////////////////////////////////

u32 system_call_read  = 0
u32 system_call_write = 1
u32 system_call_open  = 2
u32 system_call_close = 3

u32 standard_input  = 0
u32 standard_output = 1

////////////////////////////////////////////////////////////////////////////////

fast
procedure print
	in u64 message
begin
    // Not sure about casting...
	until [message] = 0 repeat
		fastcall write standard_output message 1
		inc message
	end repeat
end procedure

////////////////////////////////////////////////////////////////////////////////

fast
procedure fatal
	in u64 message
begin
	fastcall print message
	exit 1
end procedure

////////////////////////////////////////////////////////////////////////////////

fast
procedure read
	in s32 file
	in u64 data
	in u64 size
    u8 <> fatal_message = "> failed to read from the file!\n\0"
begin
	mov eax system_call_read
	mov edi file
	mov rsi data
	mov rdx size
	syscall

	if eax = -1 then
		fastcall fatal fatal_message
	end if
end procedure

////////////////////////////////////////////////////////////////////////////////

fast
procedure write
	in s32 file
	in u64 data
	in u64 size
    u8 <> fatal_message = "> failed to write to the file!\n\0"
begin
	mov eax system_call_write
	mov edi file
	mov rsi data
	mov rdx size
	syscall

	if eax = -1 then
		fastcall fatal fatal_message
	end if
end procedure

////////////////////////////////////////////////////////////////////////////////

fast
procedure open
	in u64 name
	in s32 mode
	in s32 file
begin
	mov eax system_call_open
	mov rdi name
	mov esi mode
	syscall

	if eax = -1 then
		fastcall fatal "> failed to open the file!\n\0"
	end if

	mov [file] eax
end procedure

////////////////////////////////////////////////////////////////////////////////

fast
procedure close
	in s32 file
begin
	mov eax system_call_close
	mov edi file
	syscall

	if eax = -1 then
		fastcall fatal "> failed to close the file!\n\0"
	end if
end procedure

////////////////////////////////////////////////////////////////////////////////

unix program main
	s32 file = 0
	u8  byte = 0

	s8 <> digits   = "0123456789abcdef\0"
	s8    space    = 32
	s8    new_line = 10
begin
	if argc = 2 then
		fastcall fatal "> argument count must be 2!\n\0"
	end if

	fastcall open argv 1 0 file

	until r10 = 0 repeat 
		fastcall read standard_input byte 1
		// When EOF is reached 'rax', then 'r10' is 0.
		mov r10 rax

		if u8 [byte] = 0x90 then
			fastcall print "\n\0"
		end if

		mov r12 standard_output
		mov r13 digits
		sar r15 4
		add r13 r15
		fastcall write r12 r13 1

		mov r12 standard_output
		mov r13 digits
		mov r15b [byte]
		and r15 15
		add r13 r15
		fastcall write r12 r13 1

		fastcall print " \0"
	end repeat

	fastcall print "\n\0"
	fastcall close file
end program