diff --git a/edlin.asm b/edlin.asm
index 8a3626c..4ac48db 100644
--- a/edlin.asm
+++ b/edlin.asm
@@ -68,11 +68,16 @@ int_ctrl_break equ 0x23
 	db 0x8b, 0xc0 + 8 * %1 + %2
 %endmacro
 
-%macro cmp_byteaddr_bytext 2
+; Sign extended byte to byte
+%macro cmpb_addr_ext 2
 	db 0x82, 0x3e ; cmp byte […], byte +… (extended)
 	dw %1
 	db %2
 %endmacro
+%macro cmpb_ext 2
+	db 0x82, 0xf8 + %1
+	db %2
+%endmacro
 
 jmp entrypoint
 
@@ -95,7 +100,7 @@ entrypoint: ; 0181
 	mov sp, stack.end
 
 ensure_file_argument:
-	cmp_byteaddr_bytext psp_fcb_1 + fcb_filename, ' '
+	cmpb_addr_ext psp_fcb_1 + fcb_filename, ' '
 	je print_filename_missing_error
 
 	; AL at program start a flag of whether drive specifier in first parameter valid
@@ -166,7 +171,7 @@ setup_file_parameters: ; 01ec
 	mov [psp_fcb_1 + fcb_record_size], ax
 	mov [__0a58_fcb + fcb_record_size], ax
 
-	mov dx, disk_transfer_area
+	mov dx, file_buffer
 	movw r_di, r_dx
 	mov ah, sys_set_dta
 	int 0x21
@@ -176,10 +181,10 @@ setup_file_parameters: ; 01ec
 	mov [__0a98], cx
 
 	test byte [new_file_flag], 0xff
-	jnz __0240
+	jnz initialize_editor
 
-	sub cx, disk_transfer_area
-	; cx is now the amount of memory available starting at disk_transfer_area
+	sub cx, file_buffer
+	; cx is now the amount of memory available starting at file_buffer
 
 	; __0a94 = ¼ available memory
 	shr cx, 1
@@ -190,33 +195,37 @@ setup_file_parameters: ; 01ec
 	addw r_cx, r_ax
 
 	movw r_dx, r_cx
-	add dx, disk_transfer_area
+	add dx, file_buffer
 	mov [__0a96], dx
 
 read_file:
 	mov dx, psp_fcb_1
 	mov ah, sys_random_block_read
 	int 0x21
+
 	call find_file_end_char
 	addw r_di, r_cx
 
-__0240:
+initialize_editor: ; 0240
 	cld
 
+	; Put ^Z at the end of the file in memory
 	mov byte [di], 0x1a ; ^Z
+
 	mov [__0a9a], di
 	mov byte [input_buffer.size], input_buffer.bufend - input_buffer.bufstart
 	mov byte [__0c1e], 0xff ; magic
 	mov byte [__0d48], 0x0a ; magic
-	mov word [__0a92], disk_transfer_area
-	mov word [__0a90], 1 ; magic
+	mov word [__0a92], file_buffer
+	mov word [current_line], 1
 	mov word [__0a80], 1 ; magic
 
 	test byte [new_file_flag], 0xff
-	jnz __0273
+	jnz editor_mainloop
+
 	call __0370
 
-__0273:
+editor_mainloop: ; 0273
 	mov sp, stack.end
 	mov ax, sys_set_interrupt * 0x100 + int_ctrl_break
 	mov dx, ctrl_break_handler
@@ -230,12 +239,15 @@ __0273:
 	mov ah, sys_read_line
 	int 0x21
 
-db 0xB0, 0x0A ; 028A mov al,0xa
-db 0xE8, 0x95, 0x06 ; 028C call 0x924
-db 0xC7, 0x06, 0x82, 0x0A, 0x00, 0x00 ; 028F mov word [0xa82],0x0
-db 0xC6, 0x06, 0x7D, 0x0A, 0x00 ; 0295 mov byte [0xa7d],0x0
-db 0xBE, 0x9E, 0x0A ; 029A mov si,0xa9e
-db 0xE8, 0x59, 0x00 ; 029D call 0x2f9
+	mov al, 10 ; LF
+	call print_char
+
+	mov word [__0a82], 0
+	mov byte [__0a7d], 0
+
+	mov si, input_buffer.bufstart
+	call parse_line_specifier
+
 db 0x89, 0x16, 0x80, 0x0A ; 02A0 mov [0xa80],dx
 db 0xE8, 0x43, 0x00 ; 02A4 call 0x2ea
 db 0x3C, 0x2C ; 02A7 cmp al,0x2c
@@ -265,50 +277,79 @@ db 0x72, 0x0F ; 02DE jc 0x2ef
 db 0xD1, 0xE3 ; 02E0 shl bx,1
 db 0xFF, 0x97, 0x4A, 0x03 ; 02E2 call [bx+0x34a]
 db 0xE9, 0x8A, 0xFF ; 02E6 jmp 0x273
-db 0xAC ; 02E9 lodsb
-db 0x3C, 0x20 ; 02EA cmp al,0x20
-db 0x74, 0xFB ; 02EC jz 0x2e9
-db 0xC3 ; 02EE ret
-db 0xBA, 0xF5, 0x09 ; 02EF mov dx,0x9f5
-db 0xB4, 0x09 ; 02F2 mov ah,0x9
-db 0xCD, 0x21 ; 02F4 int 0x21
-db 0xE9, 0x7A, 0xFF ; 02F6 jmp 0x273
-db 0xE8, 0xED, 0xFF ; 02F9 call 0x2e9
-db 0x3C, 0x2E ; 02FC cmp al,0x2e
-db 0x74, 0x35 ; 02FE jz 0x335
-db 0x3C, 0x23 ; 0300 cmp al,0x23
-db 0x74, 0x37 ; 0302 jz 0x33b
-db 0xBA, 0x00, 0x00 ; 0304 mov dx,0x0
-db 0xB1, 0x00 ; 0307 mov cl,0x0
-db 0x3C, 0x30 ; 0309 cmp al,0x30
-db 0x72, 0x1E ; 030B jc 0x32b
-db 0x3C, 0x39 ; 030D cmp al,0x39
-db 0x77, 0x1A ; 030F ja 0x32b
-db 0x81, 0xFA, 0x99, 0x19 ; 0311 cmp dx,0x1999
-db 0x73, 0xD8 ; 0315 jnc 0x2ef
-db 0xB1, 0x01 ; 0317 mov cl,0x1
-db 0x2C, 0x30 ; 0319 sub al,0x30
-db 0x8B, 0xDA ; 031B mov bx,dx
-db 0xD1, 0xE2 ; 031D shl dx,1
-db 0xD1, 0xE2 ; 031F shl dx,1
-db 0x03, 0xD3 ; 0321 add dx,bx
-db 0xD1, 0xE2 ; 0323 shl dx,1
-db 0x98 ; 0325 cbw
-db 0x03, 0xD0 ; 0326 add dx,ax
-db 0xAC ; 0328 lodsb
-db 0xEB, 0xDE ; 0329 jmp short 0x309
-db 0x82 ; 032B db 0x82
-db 0xF9 ; 032C stc
-db 0x00, 0x74, 0xBE ; 032D add [si-0x42],dh
-db 0x0B, 0xD2 ; 0330 or dx,dx
-db 0x74, 0xBB ; 0332 jz 0x2ef
-db 0xC3 ; 0334 ret
-db 0x8B, 0x16, 0x90, 0x0A ; 0335 mov dx,[0xa90]
-db 0xAC ; 0339 lodsb
-db 0xC3 ; 033A ret
-db 0xBA, 0xFE, 0xFF ; 033B mov dx,0xfffe
-db 0xAC ; 033E lodsb
-db 0xC3 ; 033F ret
+
+skip_spaces: ; 02e9
+	lodsb
+	cmp al, ' '
+	je skip_spaces
+	.ret: ret
+
+print_entry_error: ; 02ef
+	mov dx, entry_error
+	mov ah, sys_print_string
+	int 0x21
+	jmp editor_mainloop
+
+parse_line_specifier: ; 02f9
+	call skip_spaces
+	cmp al, '.'
+	je .current_line
+	cmp al, '#'
+	je .last_line
+
+	mov dx, 0
+	mov cl, 0 ; No digits read yet
+
+	.loop: ; 0309
+		cmp al, '0'
+		jb .not_digit
+		cmp al, '9'
+		ja .not_digit
+
+		; Would we overflow?
+		cmp dx, 65536 / 10
+		jnb print_entry_error ; Yes
+
+		mov cl, 1 ; We have now read a digit
+
+		sub al, '0'
+
+		; dx = dx*10
+		movw r_bx, r_dx
+		shl dx, 1
+		shl dx, 1
+		addw r_dx, r_bx
+		shl dx, 1
+
+		cbw
+		addw r_dx, r_ax
+
+		lodsb
+
+		jmp .loop
+
+	.not_digit: ; 032b
+		; Have we started reading a number?
+		cmpb_ext r_cl, 0
+		je skip_spaces.ret ; No
+
+		; Yes, and it's zero
+		orw r_dx, r_dx
+		jz print_entry_error
+
+		; Yes, it's nonzero
+		ret
+
+	.current_line: ; 0335
+		mov dx, [current_line]
+		lodsb
+		ret
+
+	.last_line: ; 033b
+		mov dx, 0xfffe ; TODO: Why 0xfffe and not 0xffff?
+		lodsb
+		ret
+
 db 0x51 ; 0340 push cx
 db 0x57 ; 0341 push di
 db 0x41 ; 0342 inc cx
@@ -358,7 +399,7 @@ __0370:
 	jnz __0388
 
 	cmp dx, [__0a96]
-	jnc find_file_end_char.ret
+	jnb find_file_end_char.ret
 
 __0388:
 	movw r_di, r_dx
@@ -388,7 +429,7 @@ __03ab:
 	movw r_ax, r_di
 	addw r_ax, r_cx
 	cmp ax, [__0a96]
-	jna __03ca ; disambiguate
+	jna __03ca
 
 	mov di, [__0a96]
 	movw r_cx, r_ax
@@ -870,7 +911,7 @@ oom: ; 080c
 	mov dx, oom_str
 	mov ah, sys_print_string
 	int 0x21
-	jmp __0273
+	jmp editor_mainloop
 
 db 0xB8, 0x23, 0x25 ; 0816 mov ax,0x2523
 db 0xBA, 0x7D, 0x08 ; 0819 mov dx,0x87d
@@ -1004,7 +1045,7 @@ ctrl_break_handler: ; 092d
 
 	call newline
 
-	jmp __0273
+	jmp editor_mainloop
 
 bak_extension db "BAK" ; 093e
 
@@ -1014,7 +1055,7 @@ bak_error db "Cannot edit .BAK file--rename file$" ; 0978
 directory_full_error db "No room in directory for file$" ; 099b
 __09b9 db "Disk full--file write not completed$"
 oom_str db 13, 10, "Insufficient memory", 13, 10, '$' ; 09dd
-__09f5 db "Entry error", 13, 10, '$'
+entry_error db "Entry error", 13, 10, '$' ; 09f5
 new_file_str db "New file", 13, 10, '$' ; 0a03
 __0a0e db "Not found", 13, 10, '$'
 __0a1a db "O.K.? $"
@@ -1026,15 +1067,15 @@ __0a45 db "Abort edit (Y/N)? $"
 section .bss
 __0a58_fcb: resb 37 ; 0a58 … 0a7c
 
-; 0a7d
-resb 1
+__0a7d: resb 1
 
 new_file_flag: resb 1 ; 0a7e
 __0a7f: resb 1
 
 __0a80: resw 1
-resb 14
-__0a90: resw 1
+__0a82: resw 1
+resb 12
+current_line: resw 1 ; 0a90
 __0a92: resw 1
 
 __0a94: resw 1
@@ -1060,4 +1101,4 @@ stack: resb 256 ; 0c48
 
 __0d48: resb 1
 
-disk_transfer_area: ; 0d49
+file_buffer: ; 0d49