diff --git a/README b/README
index 1a661c0..606cf41 100644
--- a/README
+++ b/README
@@ -1,3 +1,8 @@
 This is a (work in progress) disassembly of the MS-DOS 1.25 EDLIN.COM
 binary. Sources deriving from MS-DOS are under MIT license, see
 LICENSE.microsoft, while other sources are under CC0, see LICENSE.tools.
+
+Currently the code has been fully converted to assembly with symbolic
+memory references, meaning that the code can be edited and the resulting
+binary will run without problems. However, majority of the code is not yet
+understood, labeled, or commented.
diff --git a/edlin.asm b/edlin.asm
index 3c0d01e..37940bf 100644
--- a/edlin.asm
+++ b/edlin.asm
@@ -5,6 +5,7 @@ org 0x100
 fcb_filename equ 1
 fcb_extension equ fcb_filename + 8
 fcb_record_size equ 14
+fcb_rename_target equ 17
 fcb_record_low equ 33
 fcb_record_high equ 35
 
@@ -18,11 +19,14 @@ sys_print_char equ 2
 sys_print_string equ 9
 sys_read_line equ 0xa
 sys_open_file equ 0xf
+sys_close_file equ 0x10
 sys_delete_file equ 0x13
 sys_create_file equ 0x16
+sys_rename_file equ 0x17
 sys_set_dta equ 0x1a
 sys_set_interrupt equ 0x25
 sys_random_block_read equ 0x27
+sys_random_block_write equ 0x28
 
 ; Interrupt defines
 int_ctrl_break equ 0x23
@@ -46,6 +50,15 @@ int_ctrl_break equ 0x23
 %define r_dh 6
 %define r_bh 7
 
+%define b_bx_si 0
+%define b_bx_di 1
+%define b_bp_si 2
+%define b_bp_di 3
+%define b_si 4
+%define b_di 5
+%define b_bp 6
+%define b_bx 7
+
 ; Direction swapped reg, reg
 %macro addw 2
 	db 0x03, 0xc0 + 8 * %1 + %2
@@ -90,6 +103,10 @@ int_ctrl_break equ 0x23
 	dw %1
 	db %2
 %endmacro
+%macro cmpb_regind_ext 2
+	db 0x82, 0x38 + %1
+	db %2
+%endmacro
 %macro cmpb_ext 2
 	db 0x82, 0xf8 + %1
 	db %2
@@ -97,13 +114,10 @@ int_ctrl_break equ 0x23
 
 jmp entrypoint
 
-__0102:
-	db 13, 10, "The IBM Personal Computer EDITOR", 13, 10
-	db "Version 1.00 (C)Copyright IBM Corp 1981", 13, 10
-	db '$'
-
-__0150 db "Licensed Material - Program Property of IBM"
-
+; This is never used by the program
+db 13, 10, "The IBM Personal Computer EDITOR", 13, 10
+db "Version 1.00 (C)Copyright IBM Corp 1981", 13, 10, '$'
+db "Licensed Material - Program Property of IBM"
 
 print_filename_missing_error: ; 017b
 	mov dx, filename_missing_error
@@ -230,7 +244,7 @@ initialize_editor: ; 0240
 
 	mov [__0a9a], di
 	mov byte [input_buffer.size], input_buffer.bufend - input_buffer.bufstart
-	mov byte [__0c1e], 0xff ; magic
+	mov byte [__0c1e.size], 0xff
 	mov byte [__0d48], 0x0a ; magic
 	mov word [__0a92], file_buffer
 	mov word [current_line], 1
@@ -417,7 +431,7 @@ find_file_end_char: ; 035e
 __036d:
 	jmp print_eof_str
 
-command_a:
+command_a: ; 0370
 	test byte [new_file_flag], 0xff
 	jnz __036d
 
@@ -508,47 +522,60 @@ _trampoline_oom_1: ; 0414
 	jmp oom
 
 command_w: ; 0417
-db 0x8B, 0x1E, 0x80, 0x0A ; 0417 mov bx,[0xa80]
-db 0x0B, 0xDB ; 041B or bx,bx
-db 0x75, 0x1C ; 041D jnz 0x43b
-db 0x8B, 0x0E, 0x94, 0x0A ; 041F mov cx,[0xa94]
-db 0x8B, 0x3E, 0x9A, 0x0A ; 0423 mov di,[0xa9a]
-db 0x2B, 0xF9 ; 0427 sub di,cx
-db 0x76, 0xDA ; 0429 jna 0x405
-db 0x81, 0xFF, 0x49, 0x0D ; 042B cmp di,0xd49
-db 0x76, 0xD4 ; 042F jna 0x405
-db 0x33, 0xD2 ; 0431 xor dx,dx
-db 0xBB, 0x01, 0x00 ; 0433 mov bx,0x1
-db 0xE8, 0x6B, 0x00 ; 0436 call 0x4a4
-db 0xEB, 0x04 ; 0439 jmp short 0x43f
-db 0x43 ; 043B inc bx
-db 0xE8, 0x43, 0x00 ; 043C call 0x482
-db 0x8B, 0xCF ; 043F mov cx,di
-db 0xBA, 0x49, 0x0D ; 0441 mov dx,0xd49
-db 0x2B, 0xCA ; 0444 sub cx,dx
-db 0x74, 0xBD ; 0446 jz 0x405
-db 0xB4, 0x1A ; 0448 mov ah,0x1a
-db 0xCD, 0x21 ; 044A int 0x21
-db 0xBA, 0x58, 0x0A ; 044C mov dx,0xa58
-db 0xB4, 0x28 ; 044F mov ah,0x28
-db 0xCD, 0x21 ; 0451 int 0x21
-db 0x0A, 0xC0 ; 0453 or al,al
-db 0x75, 0x1E ; 0455 jnz 0x475
-db 0x8B, 0xF7 ; 0457 mov si,di
-db 0xBF, 0x49, 0x0D ; 0459 mov di,0xd49
-db 0x89, 0x3E, 0x92, 0x0A ; 045C mov [0xa92],di
-db 0x8B, 0x0E, 0x9A, 0x0A ; 0460 mov cx,[0xa9a]
-db 0x2B, 0xCE ; 0464 sub cx,si
-db 0x41 ; 0466 inc cx
-db 0xF3, 0xA4 ; 0467 rep movsb
-db 0x4F ; 0469 dec di
-db 0x89, 0x3E, 0x9A, 0x0A ; 046A mov [0xa9a],di
-db 0xC7, 0x06, 0x90, 0x0A, 0x01, 0x00 ; 046E mov word [0xa90],0x1
+	mov bx, [__0a80]
+	orw r_bx, r_bx
+	jnz __043b
+
+	mov cx, [__0a94]
+	mov di, [__0a9a]
+	subw r_di, r_cx
+	jna print_eof_str.ret
+
+	cmp di, file_buffer
+	jna print_eof_str.ret
+
+	xorw r_dx, r_dx
+	mov bx, 1 ; magic
+	call __04a4
+
+	jmp __043f
+
+__043b:
+	inc bx
+	call __0482
+
+__043f:
+	movw r_cx, r_di
+	mov dx, file_buffer
+	subw r_cx, r_dx
+	je print_eof_str.ret
+	mov ah, sys_set_dta
+	int 0x21
+
+	mov dx, __0a58_fcb
+	mov ah, sys_random_block_write
+	int 0x21
+	orb r_al, r_al
+	jnz disk_full
+
+	movw r_si, r_di
+	mov di, file_buffer
+	mov [__0a92], di
+	mov cx, [__0a9a]
+	subw r_cx, r_si
+	inc cx
+	rep movsb
+	dec di
+	mov [__0a9a], di
+	mov word [current_line], 1
+
 __0474:
-db 0xC3 ; 0474 ret
-db 0xB4, 0x10 ; 0475 mov ah,0x10
-db 0xCD, 0x21 ; 0477 int 0x21
-db 0xBA, 0xB9, 0x09 ; 0479 mov dx,0x9b9
+	ret
+
+disk_full: ; 0475
+	mov ah, sys_close_file
+	int 0x21
+	mov dx, disk_full_error
 
 error: ; 047c
 	mov ah, sys_print_string
@@ -556,19 +583,21 @@ error: ; 047c
 	int 0x20
 
 __0482:
-db 0x8B, 0x16, 0x90, 0x0A ; 0482 mov dx,[0xa90]
-db 0x8B, 0x3E, 0x92, 0x0A ; 0486 mov di,[0xa92]
-db 0x3B, 0xDA ; 048A cmp bx,dx
-db 0x74, 0xE6 ; 048C jz 0x474
-db 0x77, 0x0E ; 048E ja 0x49e
-db 0x0B, 0xDB ; 0490 or bx,bx
-db 0x74, 0x0A ; 0492 jz 0x49e
-db 0xBA, 0x01, 0x00 ; 0494 mov dx,0x1
-db 0xBF, 0x49, 0x0D ; 0497 mov di,0xd49
-db 0x3B, 0xDA ; 049A cmp bx,dx
-db 0x74, 0xD6 ; 049C jz 0x474
-db 0x8B, 0x0E, 0x9A, 0x0A ; 049E mov cx,[0xa9a]
-db 0x2B, 0xCF ; 04A2 sub cx,di
+	mov dx, [current_line]
+	mov di, [__0a92]
+	cmpw r_bx, r_dx
+	je __0474
+	ja __049e
+
+	orw r_bx, r_bx
+	jz __049e
+	mov dx, 1 ; magic
+	mov di, file_buffer
+	cmpw r_bx, r_dx
+	je __0474
+__049e:
+	mov cx, [__0a9a]
+	subw r_cx, r_di
 
 __04a4:
 	mov al, 10 ; magic
@@ -579,6 +608,7 @@ __04a8:
 	inc dx
 	cmpw r_bx, r_dx
 	jnz __04a8
+__04b1:
 	ret
 
 print_line_prefix: ; 04b2
@@ -656,25 +686,28 @@ print_bcd_digit: ; 0501
 	jmp print_char
 
 command_l: ; 050e
-db 0x8B, 0x1E, 0x80, 0x0A ; 050E mov bx,[0xa80]
-db 0x0B, 0xDB ; 0512 or bx,bx
-db 0x75, 0x0C ; 0514 jnz 0x522
-db 0x8B, 0x1E, 0x90, 0x0A ; 0516 mov bx,[0xa90]
-db 0x83, 0xEB, 0x0B ; 051A sub bx,byte +0xb
-db 0x77, 0x03 ; 051D ja 0x522
-db 0xBB, 0x01, 0x00 ; 051F mov bx,0x1
-db 0xE8, 0x5D, 0xFF ; 0522 call 0x482
-db 0x75, 0x8A ; 0525 jnz 0x4b1
-db 0x8B, 0xF7 ; 0527 mov si,di
-db 0x8B, 0x3E, 0x82, 0x0A ; 0529 mov di,[0xa82]
-db 0x47 ; 052D inc di
-db 0x2B, 0xFB ; 052E sub di,bx
-db 0x77, 0x08 ; 0530 ja 0x53a
-db 0xBF, 0x17, 0x00 ; 0532 mov di,0x17
-db 0xEB, 0x03 ; 0535 jmp short 0x53a
+	mov bx, [__0a80]
+	orw r_bx, r_bx
+	jnz __0522
+
+	mov bx, [current_line]
+	sub bx, 11 ; magic
+	ja __0522
+	mov bx, 1
+__0522:
+	call __0482
+	jnz __04b1 ; disambiguate
+	movw r_si, r_di
+	mov di, [__0a82]
+	inc di
+	subw r_di, r_bx
+	ja __053a
+	mov di, 0x17 ; magic
+	jmp __053a
 
 __0537:
 	mov di, 1 ; magic
+__053a:
 	mov cx, [__0a9a]
 	subw r_cx, r_si
 	jz print_line.ret
@@ -722,81 +755,116 @@ print_line: ; 0546
 
 	.ret: ret
 
-db 0xBF, 0x20, 0x0C ; 0574 mov di,0xc20
-db 0xB9, 0xFF, 0x00 ; 0577 mov cx,0xff
-db 0xBA, 0xFF, 0xFF ; 057A mov dx,0xffff
-db 0xAC ; 057D lodsb
-db 0xAA ; 057E stosb
-db 0x42 ; 057F inc dx
-db 0x3C, 0x0D ; 0580 cmp al,0xd
-db 0xE0, 0xF9 ; 0582 loopne 0x57d
-db 0x88, 0x16, 0x1F, 0x0C ; 0584 mov [0xc1f],dl
-db 0x74, 0xE9 ; 0588 jz 0x573
-db 0xAC ; 058A lodsb
-db 0x42 ; 058B inc dx
-db 0x3C, 0x0D ; 058C cmp al,0xd
-db 0x75, 0xFA ; 058E jnz 0x58a
-db 0x4F ; 0590 dec di
-db 0xAA ; 0591 stosb
-db 0xC3 ; 0592 ret
-db 0xE9, 0xC9, 0x00 ; 0593 jmp 0x65f
+; in:
+;  si = line
+; out:
+;  dx = length of line (untruncated)
+; NOTE: Always ends a line with CR
+__0574:
+	mov di, __0c1e.bufstart
+	mov cx, 255 ; Maximum line length
+	mov dx, -1 ; Start off at -1 since the loop increases dx before testing
+
+	.copyloop: ; 057d
+		lodsb
+		stosb
+		inc dx
+		cmp al, 13 ; CR
+		loopne .copyloop
+
+	mov [__0c1e.fill], dl
+	je print_line.ret
+
+	.find_cr: ; 058a
+		lodsb
+		inc dx
+		cmp al, 13 ; CR
+		jnz .find_cr
+
+	; Overwrite last character with CR
+	dec di
+	stosb
+	ret
+
+__0593:
+	jmp print_not_found_str
 
 command_r: ; 0596
-db 0xE8, 0xFD, 0x00 ; 0596 call 0x696
-db 0x75, 0xF8 ; 0599 jnz 0x593
-db 0x8B, 0x36, 0x8C, 0x0A ; 059B mov si,[0xa8c]
-db 0xE8, 0xD2, 0xFF ; 059F call 0x574
-db 0x2B, 0x16, 0x84, 0x0A ; 05A2 sub dx,[0xa84]
-db 0x8B, 0x0E, 0x86, 0x0A ; 05A6 mov cx,[0xa86]
-db 0x03, 0xD1 ; 05AA add dx,cx
-db 0x81, 0xFA, 0xFE, 0x00 ; 05AC cmp dx,0xfe
-db 0x77, 0x70 ; 05B0 ja 0x622
-db 0x8B, 0x1E, 0x8A, 0x0A ; 05B2 mov bx,[0xa8a]
-db 0x52 ; 05B6 push dx
-db 0xE8, 0xF8, 0xFE ; 05B7 call 0x4b2
-db 0x5A ; 05BA pop dx
-db 0x8B, 0x0E, 0x88, 0x0A ; 05BB mov cx,[0xa88]
-db 0x8B, 0x36, 0x8C, 0x0A ; 05BF mov si,[0xa8c]
-db 0x2B, 0xCE ; 05C3 sub cx,si
-db 0x49 ; 05C5 dec cx
-db 0xE8, 0x4F, 0x00 ; 05C6 call 0x618
-db 0x56 ; 05C9 push si
-db 0xBE, 0x9E, 0x0B ; 05CA mov si,0xb9e
-db 0x8B, 0x0E, 0x86, 0x0A ; 05CD mov cx,[0xa86]
-db 0xE8, 0x44, 0x00 ; 05D1 call 0x618
-db 0x5E ; 05D4 pop si
-db 0x03, 0x36, 0x84, 0x0A ; 05D5 add si,[0xa84]
-db 0x8B, 0xCA ; 05D9 mov cx,dx
-db 0x83, 0xC1, 0x02 ; 05DB add cx,byte +0x2
-db 0xE8, 0x37, 0x00 ; 05DE call 0x618
-db 0xE8, 0x90, 0x00 ; 05E1 call 0x674
-db 0x75, 0x2A ; 05E4 jnz 0x610
-db 0xE8, 0x7E, 0x00 ; 05E6 call 0x667
-db 0x8B, 0x3E, 0x88, 0x0A ; 05E9 mov di,[0xa88]
-db 0x4F ; 05ED dec di
-db 0xBE, 0x9E, 0x0B ; 05EE mov si,0xb9e
-db 0x8B, 0x16, 0x84, 0x0A ; 05F1 mov dx,[0xa84]
-db 0x8B, 0x0E, 0x86, 0x0A ; 05F5 mov cx,[0xa86]
-db 0x49 ; 05F9 dec cx
-db 0x01, 0x0E, 0x88, 0x0A ; 05FA add [0xa88],cx
-db 0x41 ; 05FE inc cx
-db 0x4A ; 05FF dec dx
-db 0x29, 0x16, 0x8E, 0x0A ; 0600 sub [0xa8e],dx
-db 0x73, 0x06 ; 0604 jnc 0x60c
-db 0xC7, 0x06, 0x8E, 0x0A, 0x00, 0x00 ; 0606 mov word [0xa8e],0x0
-db 0x42 ; 060C inc dx
-db 0xE8, 0xC7, 0x01 ; 060D call 0x7d7
-db 0xE8, 0xDC, 0x00 ; 0610 call 0x6ef
-db 0x75, 0x0C ; 0613 jnz 0x621
-db 0xE9, 0x83, 0xFF ; 0615 jmp 0x59b
-db 0xE3, 0x07 ; 0618 jcxz 0x621
-db 0xAC ; 061A lodsb
-db 0xE8, 0x06, 0x03 ; 061B call 0x924
-db 0x4A ; 061E dec dx
-db 0xE2, 0xF9 ; 061F loop 0x61a
-db 0xC3 ; 0621 ret
-db 0xBA, 0x21, 0x0A ; 0622 mov dx,0xa21
-db 0xEB, 0x3B ; 0625 jmp short 0x662
+	call __0696
+	jnz __0593 ; disambiguate
+
+__059b:
+	mov si, [__0a8c]
+	call __0574
+	sub dx, [__0a84]
+	mov cx, [__0a86]
+	addw r_dx, r_cx
+
+	cmp dx, 0xfe ; magic
+	ja __0622
+
+	mov bx, [__0a8a]
+	push dx
+	call print_line_prefix
+	pop dx
+
+	mov cx, [__0a88]
+	mov si, [__0a8c]
+	subw r_cx, r_si
+	dec cx
+	call __0618
+
+	push si
+	mov si, __0b9e
+	mov cx, [__0a86]
+	call __0618
+	pop si
+
+	add si, [__0a84]
+	movw r_cx, r_dx
+	add cx, 2 ; magic
+	call __0618
+
+	call prompt_okay
+	jne __0610 ; User didn't okay
+
+	call __0667
+	mov di, [__0a88]
+	dec di
+	mov si, __0b9e
+	mov dx, [__0a84]
+	mov cx, [__0a86]
+	dec cx
+	add [__0a88], cx
+	inc cx
+	dec dx
+	sub [__0a8e], dx
+	jnb __060c
+	mov word [__0a8e], 0
+
+__060c:
+	inc dx
+	call __07d7
+
+__0610:
+	call __06ef
+	jnz __0621 ; disambiguate
+	jmp near __059b
+
+__0618:
+	jcxz __0621
+__061a:
+	lodsb
+	call print_char
+	dec dx
+	loop __061a
+
+__0621:
+	ret
+
+__0622:
+	mov dx, line_too_long_error
+	jmp print_string
 
 command_s: ; 0627
 	call __0696
@@ -825,6 +893,7 @@ __062c:
 
 print_not_found_str: ; 065f
 	mov dx, not_found_str
+print_string: ; 0662
 	mov ah, sys_print_string
 	int 0x21
 	ret
@@ -967,88 +1036,120 @@ copy_line: ; 073f
 		jmp .loop
 
 command_d: ; 074e
-db 0x8B, 0x1E, 0x80, 0x0A ; 074E mov bx,[0xa80]
-db 0x0B, 0xDB ; 0752 or bx,bx
-db 0x75, 0x04 ; 0754 jnz 0x75a
-db 0x8B, 0x1E, 0x90, 0x0A ; 0756 mov bx,[0xa90]
-db 0xE8, 0x25, 0xFD ; 075A call 0x482
-db 0x75, 0xDF ; 075D jnz 0x73e
-db 0x53 ; 075F push bx
-db 0x57 ; 0760 push di
-db 0x8B, 0x1E, 0x82, 0x0A ; 0761 mov bx,[0xa82]
-db 0x0B, 0xDB ; 0765 or bx,bx
-db 0x75, 0x02 ; 0767 jnz 0x76b
-db 0x8B, 0xDA ; 0769 mov bx,dx
-db 0x43 ; 076B inc bx
-db 0xE8, 0x13, 0xFD ; 076C call 0x482
-db 0x8B, 0xD7 ; 076F mov dx,di
-db 0x5F ; 0771 pop di
-db 0x2B, 0xD7 ; 0772 sub dx,di
-db 0x76, 0x0C ; 0774 jna 0x782
-db 0x8F, 0x06, 0x90, 0x0A ; 0776 pop word [0xa90]
-db 0x89, 0x3E, 0x92, 0x0A ; 077A mov [0xa92],di
-db 0x33, 0xC9 ; 077E xor cx,cx
-db 0xEB, 0x55 ; 0780 jmp short 0x7d7
-db 0xE9, 0x6A, 0xFB ; 0782 jmp 0x2ef
+	mov bx, [__0a80]
+	orw r_bx, r_bx
+	jnz __075a
+
+	mov bx, [current_line]
+__075a:
+	call __0482
+	jnz __073e ; disambiguate
+
+	push bx
+	push di
+	mov bx, [__0a82]
+	orw r_bx, r_bx
+	jnz __076b
+	movw r_bx, r_dx
+
+__076b:
+	inc bx
+	call __0482
+	movw r_dx, r_di
+	pop di
+	subw r_dx, r_di
+	jna __0782
+
+	pop word [current_line]
+	mov [__0a92], di
+	xorw r_cx, r_cx
+	jmp __07d7
+
+__0782:
+	jmp print_entry_error
 
 command_cr: ; 0785
-db 0x8B, 0x1E, 0x80, 0x0A ; 0785 mov bx,[0xa80]
-db 0x0B, 0xDB ; 0789 or bx,bx
-db 0x75, 0x05 ; 078B jnz 0x792
-db 0x8B, 0x1E, 0x90, 0x0A ; 078D mov bx,[0xa90]
-db 0x43 ; 0791 inc bx
-db 0xE8, 0xED, 0xFC ; 0792 call 0x482
-db 0x8B, 0xF7 ; 0795 mov si,di
-db 0x89, 0x16, 0x90, 0x0A ; 0797 mov [0xa90],dx
-db 0x89, 0x36, 0x92, 0x0A ; 079B mov [0xa92],si
-db 0x75, 0x9D ; 079F jnz 0x73e
-db 0x3B, 0x36, 0x9A, 0x0A ; 07A1 cmp si,[0xa9a]
-db 0x74, 0x97 ; 07A5 jz 0x73e
-db 0xE8, 0xCA, 0xFD ; 07A7 call 0x574
-db 0x89, 0x16, 0x84, 0x0A ; 07AA mov [0xa84],dx
-db 0x8B, 0x36, 0x92, 0x0A ; 07AE mov si,[0xa92]
-db 0xE8, 0x82, 0xFD ; 07B2 call 0x537
-db 0xE8, 0xFA, 0xFC ; 07B5 call 0x4b2
-db 0xB4, 0x0A ; 07B8 mov ah,0xa
-db 0xBA, 0x1E, 0x0C ; 07BA mov dx,0xc1e
-db 0xCD, 0x21 ; 07BD int 0x21
-db 0xB0, 0x0A ; 07BF mov al,0xa
-db 0xE8, 0x60, 0x01 ; 07C1 call 0x924
-db 0x8A, 0x0E, 0x1F, 0x0C ; 07C4 mov cl,[0xc1f]
-db 0xB5, 0x00 ; 07C8 mov ch,0x0
-db 0xE3, 0x3F ; 07CA jcxz 0x80b
-db 0x8B, 0x16, 0x84, 0x0A ; 07CC mov dx,[0xa84]
-db 0xBE, 0x20, 0x0C ; 07D0 mov si,0xc20
-db 0x8B, 0x3E, 0x92, 0x0A ; 07D3 mov di,[0xa92]
-db 0x3B, 0xCA ; 07D7 cmp cx,dx
-db 0x74, 0x2E ; 07D9 jz 0x809
-db 0x56 ; 07DB push si
-db 0x57 ; 07DC push di
-db 0x51 ; 07DD push cx
-db 0x8B, 0xF7 ; 07DE mov si,di
-db 0x03, 0xF2 ; 07E0 add si,dx
-db 0x03, 0xF9 ; 07E2 add di,cx
-db 0xA1, 0x9A, 0x0A ; 07E4 mov ax,[0xa9a]
-db 0x2B, 0xC2 ; 07E7 sub ax,dx
-db 0x03, 0xC1 ; 07E9 add ax,cx
-db 0x3B, 0x06, 0x98, 0x0A ; 07EB cmp ax,[0xa98]
-db 0x73, 0x1B ; 07EF jnc 0x80c
-db 0x87, 0x06, 0x9A, 0x0A ; 07F1 xchg ax,[0xa9a]
-db 0x8B, 0xC8 ; 07F5 mov cx,ax
-db 0x2B, 0xCE ; 07F7 sub cx,si
-db 0x3B, 0xF7 ; 07F9 cmp si,di
-db 0x77, 0x05 ; 07FB ja 0x802
-db 0x03, 0xF1 ; 07FD add si,cx
-db 0x03, 0xF9 ; 07FF add di,cx
-db 0xFD ; 0801 std
-db 0x41 ; 0802 inc cx
-db 0xF3, 0xA4 ; 0803 rep movsb
-db 0xFC ; 0805 cld
-db 0x59 ; 0806 pop cx
-db 0x5F ; 0807 pop di
-db 0x5E ; 0808 pop si
-db 0xF3, 0xA4 ; 0809 rep movsb
-db 0xC3 ; 080B ret
+	mov bx, [__0a80]
+	orw r_bx, r_bx
+	jnz __0792
+
+	mov bx, [current_line]
+	inc bx
+
+__0792:
+	call __0482
+	movw r_si, r_di
+	mov [current_line], dx
+	mov [__0a92], si
+	jnz __073e ; disambiguate
+
+	cmp si, [__0a9a]
+	je __073e
+
+	call __0574
+
+	mov [__0a84], dx
+	mov si, [__0a92]
+	call __0537
+	call print_line_prefix
+
+	mov ah, sys_read_line
+	mov dx, __0c1e
+	int 0x21
+
+	mov al, 10 ; LF
+	call print_char
+
+	mov cl, [__0c1e.fill]
+	mov ch, 0
+	jcxz __080b
+
+	mov dx, [__0a84]
+	mov si, __0c1e.bufstart
+	mov di, [__0a92]
+
+__07d7:
+	cmpw r_cx, r_dx
+	je __0809
+
+	push si
+	push di
+	push cx
+
+	movw r_si, r_di
+	addw r_si, r_dx
+	addw r_di, r_cx
+	mov ax, [__0a9a]
+	subw r_ax, r_dx
+	addw r_ax, r_cx
+	cmp ax, [__0a98]
+	jnb oom
+
+	xchg ax, [__0a9a]
+	movw r_cx, r_ax
+	subw r_cx, r_si
+	; NOTE: Memmove?
+	cmpw r_si, r_di
+	ja __0802
+
+	addw r_si, r_cx
+	addw r_di, r_cx
+	std
+
+__0802:
+	inc cx
+	rep movsb
+	cld
+
+	pop cx
+	pop di
+	pop si
+
+__0809:
+	rep movsb
+
+__080b:
+	ret
 
 oom: ; 080c
 	mov dx, oom_str
@@ -1057,122 +1158,155 @@ oom: ; 080c
 	jmp editor_mainloop
 
 command_i: ; 0816
-db 0xB8, 0x23, 0x25 ; 0816 mov ax,0x2523
-db 0xBA, 0x7D, 0x08 ; 0819 mov dx,0x87d
-db 0xCD, 0x21 ; 081C int 0x21
-db 0x8B, 0x1E, 0x80, 0x0A ; 081E mov bx,[0xa80]
-db 0x0B, 0xDB ; 0822 or bx,bx
-db 0x75, 0x04 ; 0824 jnz 0x82a
-db 0x8B, 0x1E, 0x90, 0x0A ; 0826 mov bx,[0xa90]
-db 0xE8, 0x55, 0xFC ; 082A call 0x482
-db 0x8B, 0x0E, 0x9A, 0x0A ; 082D mov cx,[0xa9a]
-db 0x8B, 0xF1 ; 0831 mov si,cx
-db 0x2B, 0xCF ; 0833 sub cx,di
-db 0x41 ; 0835 inc cx
-db 0x8B, 0x3E, 0x98, 0x0A ; 0836 mov di,[0xa98]
-db 0xFD ; 083A std
-db 0xF3, 0xA4 ; 083B rep movsb
-db 0x87, 0xFE ; 083D xchg di,si
-db 0xFC ; 083F cld
-db 0x47 ; 0840 inc di
-db 0x8B, 0xEE ; 0841 mov bp,si
-db 0x8B, 0xDA ; 0843 mov bx,dx
-db 0x89, 0x3E, 0x92, 0x0A ; 0845 mov [0xa92],di
-db 0x89, 0x1E, 0x90, 0x0A ; 0849 mov [0xa90],bx
-db 0x89, 0x2E, 0x9A, 0x0A ; 084D mov [0xa9a],bp
-db 0xE8, 0x5E, 0xFC ; 0851 call 0x4b2
-db 0xBA, 0x1E, 0x0C ; 0854 mov dx,0xc1e
-db 0xB4, 0x0A ; 0857 mov ah,0xa
-db 0xCD, 0x21 ; 0859 int 0x21
-db 0xE8, 0xC4, 0x00 ; 085B call 0x922
-db 0xBE, 0x20, 0x0C ; 085E mov si,0xc20
-db 0x82 ; 0861 db 0x82
-db 0x3C, 0x1A ; 0862 cmp al,0x1a
-db 0x74, 0x25 ; 0864 jz 0x88b
-db 0x8A, 0x4C, 0xFF ; 0866 mov cl,[si-0x1]
-db 0xB5, 0x00 ; 0869 mov ch,0x0
-db 0x8B, 0xD6 ; 086B mov dx,si
-db 0x03, 0xD1 ; 086D add dx,cx
-db 0x42 ; 086F inc dx
-db 0x3B, 0xD5 ; 0870 cmp dx,bp
-db 0x73, 0x98 ; 0872 jnc 0x80c
-db 0xF3, 0xA4 ; 0874 rep movsb
-db 0xA4 ; 0876 movsb
-db 0xB0, 0x0A ; 0877 mov al,0xa
-db 0xAA ; 0879 stosb
-db 0x43 ; 087A inc bx
-db 0xEB, 0xC8 ; 087B jmp short 0x845
-db 0x8C, 0xC8 ; 087D mov ax,cs
-db 0x8E, 0xD8 ; 087F mov ds,ax
-db 0x8E, 0xC0 ; 0881 mov es,ax
-db 0x8E, 0xD0 ; 0883 mov ss,ax
-db 0xBC, 0x48, 0x0D ; 0885 mov sp,0xd48
-db 0xE8, 0x92, 0x00 ; 0888 call 0x91d
-db 0x8B, 0x2E, 0x9A, 0x0A ; 088B mov bp,[0xa9a]
-db 0x8B, 0x3E, 0x92, 0x0A ; 088F mov di,[0xa92]
-db 0x8B, 0xF5 ; 0893 mov si,bp
-db 0x46 ; 0895 inc si
-db 0x8B, 0x0E, 0x98, 0x0A ; 0896 mov cx,[0xa98]
-db 0x2B, 0xCD ; 089A sub cx,bp
-db 0xF3, 0xA4 ; 089C rep movsb
-db 0x4F ; 089E dec di
-db 0x89, 0x3E, 0x9A, 0x0A ; 089F mov [0xa9a],di
-db 0xE9, 0xCD, 0xF9 ; 08A3 jmp 0x273
+	mov ax, sys_set_interrupt * 0x100 + int_ctrl_break
+	mov dx, __087d
+	int 0x21
+
+	mov bx, [__0a80],
+	orw r_bx, r_bx
+	jnz __082a
+	mov bx, [current_line]
+
+__082a:
+	call __0482
+	mov cx, [__0a9a]
+	movw r_si, r_cx
+	subw r_cx, r_di
+	inc cx
+	mov di, [__0a98]
+
+	std
+	rep movsb
+	xchg di, si
+	cld
+
+	inc di
+	movw r_bp, r_si
+	movw r_bx, r_dx
+__0845:
+	mov [__0a92], di
+	mov [current_line], bx
+	mov [__0a9a], bp
+	call print_line_prefix
+
+	mov dx, __0c1e
+	mov ah, sys_read_line
+	int 0x21
+
+	call __0922
+
+	mov si, __0c1e.bufstart
+
+	cmpb_regind_ext b_si, 0x1a ; ^Z
+	je __088b
+
+	mov cl, [si - 1] ; magic
+	mov ch, 0
+
+	movw r_dx, r_si
+	addw r_dx, r_cx
+	inc dx
+	cmpw r_dx, r_bp
+	jnb oom
+
+	rep movsb
+	movsb
+	mov al, 10 ; magic, LF?
+	stosb
+
+	inc bx
+	jmp __0845
+
+__087d:
+	mov ax, cs
+	mov ds, ax
+	mov es, ax
+	mov ss, ax
+	mov sp, stack.end
+	call newline
+
+__088b:
+	mov bp, [__0a9a]
+	mov di, [__0a92]
+	movw r_si, r_bp
+	inc si
+	mov cx, [__0a98]
+	subw r_cx, r_bp
+	rep movsb
+	dec di
+	mov [__0a9a], di
+	jmp editor_mainloop
 
 command_q: ; 08a6
-db 0xBA, 0x45, 0x0A ; 08A6 mov dx,0xa45
-db 0xB4, 0x09 ; 08A9 mov ah,0x9
-db 0xCD, 0x21 ; 08AB int 0x21
-db 0xB4, 0x01 ; 08AD mov ah,0x1
-db 0xCD, 0x21 ; 08AF int 0x21
-db 0x24, 0x5F ; 08B1 and al,0x5f
-db 0x3C, 0x59 ; 08B3 cmp al,0x59
-db 0x75, 0x66 ; 08B5 jnz 0x91d
-db 0xBA, 0x58, 0x0A ; 08B7 mov dx,0xa58
-db 0xB4, 0x10 ; 08BA mov ah,0x10
-db 0xCD, 0x21 ; 08BC int 0x21
-db 0xB4, 0x13 ; 08BE mov ah,0x13
-db 0xCD, 0x21 ; 08C0 int 0x21
-db 0xCD, 0x20 ; 08C2 int 0x20
-db 0xC7, 0x06, 0x80, 0x0A, 0xFF, 0xFF ; 08C4 mov word [0xa80],0xffff
-db 0xE8, 0xA3, 0xFA ; 08CA call 0x370
+	mov dx, quit_prompt
+	mov ah, sys_print_string
+	int 0x21
+
+	mov ah, sys_read_char
+	int 0x21
+	and al, 0x5f ; Lowercase
+	cmp al, 'Y'
+	jne newline
+
+	mov dx, __0a58_fcb
+	mov ah, sys_close_file
+	int 0x21
+
+	mov ah, sys_delete_file
+	int 0x21
+
+	int 0x20
+
+__08c4:
+	mov word [__0a80], 0xffff ; magic
+	call command_a
 
 command_e: ; 08cd
-db 0xC6, 0x06, 0x7F, 0x0A, 0x01 ; 08CD mov byte [0xa7f],0x1
-db 0xBB, 0xFF, 0xFF ; 08D2 mov bx,0xffff
-db 0xE8, 0x63, 0xFB ; 08D5 call 0x43b
-db 0xF6, 0x06, 0x7E, 0x0A, 0xFF ; 08D8 test byte [0xa7e],0xff
-db 0x74, 0xE5 ; 08DD jz 0x8c4
-db 0x8B, 0x16, 0x9A, 0x0A ; 08DF mov dx,[0xa9a]
-db 0xB4, 0x1A ; 08E3 mov ah,0x1a
-db 0xCD, 0x21 ; 08E5 int 0x21
-db 0xB9, 0x01, 0x00 ; 08E7 mov cx,0x1
-db 0xBA, 0x58, 0x0A ; 08EA mov dx,0xa58
-db 0xB4, 0x28 ; 08ED mov ah,0x28
-db 0xCD, 0x21 ; 08EF int 0x21
-db 0xB4, 0x10 ; 08F1 mov ah,0x10
-db 0xCD, 0x21 ; 08F3 int 0x21
-db 0xBE, 0x5C, 0x00 ; 08F5 mov si,0x5c
-db 0x8D, 0x7C, 0x10 ; 08F8 lea di,[si+0x10]
-db 0x8B, 0xD6 ; 08FB mov dx,si
-db 0xB9, 0x09, 0x00 ; 08FD mov cx,0x9
-db 0xF3, 0xA4 ; 0900 rep movsb
-db 0xBE, 0x3E, 0x09 ; 0902 mov si,0x93e
-db 0xA5 ; 0905 movsw
-db 0xA4 ; 0906 movsb
-db 0xB4, 0x17 ; 0907 mov ah,0x17
-db 0xCD, 0x21 ; 0909 int 0x21
-db 0xBE, 0x5C, 0x00 ; 090B mov si,0x5c
-db 0xBF, 0x68, 0x0A ; 090E mov di,0xa68
-db 0xB9, 0x06, 0x00 ; 0911 mov cx,0x6
-db 0xF3, 0xA5 ; 0914 rep movsw
-db 0xBA, 0x58, 0x0A ; 0916 mov dx,0xa58
-db 0xCD, 0x21 ; 0919 int 0x21
-db 0xCD, 0x20 ; 091B int 0x20
+	mov byte [__0a7f], 1 ; magic
+	mov bx, 0xffff ; magic
+	call __043b
+	test byte [new_file_flag], 0xff
+	jz __08c4
+
+	mov dx, [__0a9a]
+	mov ah, sys_set_dta
+	int 0x21
+
+	mov cx, 1
+	mov dx, __0a58_fcb
+	mov ah, sys_random_block_write
+	int 0x21
+
+	mov ah, sys_close_file
+	int 0x21
+
+	mov si, psp_fcb_1
+	; NOTE: - 1 since this copies the drive specifier (which is ignored?) too
+	lea di, [si + fcb_rename_target - 1]
+	movw r_dx, r_si
+	mov cx, 9
+	rep movsb
+	mov si, bak_extension
+	movsw
+	movsb
+
+	mov ah, sys_rename_file
+	int 0x21
+
+	mov si, psp_fcb_1
+	mov di, __0a58_fcb + fcb_rename_target - 1
+	mov cx, 6 ; 6*2 = 12 bytes (as we copy words). 1 (drive specifier) + 8 (name) + 3 (extension)
+	rep movsw
+
+	mov dx, __0a58_fcb
+	int 0x21
+
+	int 0x20
 
 newline: ; 091d
 	mov al, 13 ; CR
 	call print_char
+__0922:
 	mov al, 10 ; LF
 
 print_char: ; 0924
@@ -1201,15 +1335,15 @@ invalid_name_error db "Invalid drive or file name$" ; 0941
 filename_missing_error db "File name must be specified$" ; 095c
 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$"
+disk_full_error db "Disk full--file write not completed$"
 oom_str db 13, 10, "Insufficient memory", 13, 10, '$' ; 09dd
 entry_error db "Entry error", 13, 10, '$' ; 09f5
 new_file_str db "New file", 13, 10, '$' ; 0a03
 not_found_str db "Not found", 13, 10, '$' ; 0a0e
 ok_prompt db "O.K.? $" ; 0a1a
-__0a21 db "Line too long", 13, 10, '$'
+line_too_long_error db "Line too long", 13, 10, '$' ; 0a21
 eof_str db "End of input file", 13, 10, '$' ; 0a31
-__0a45 db "Abort edit (Y/N)? $"
+quit_prompt db "Abort edit (Y/N)? $" ; 0a45
 
 ; 0a58
 section .bss
@@ -1246,11 +1380,14 @@ input_buffer:
 __0b1e resb 128
 __0b9e resb 128
 
-__0c1e resb 1
+__0c1e:
+	.size resb 1 ; 0c1e
+	.fill resb 1 ; 0c1f
+	; TODO: Figure if this is 256 or 255 bytes
+	.bufstart resb 256 ; 0c20
+	.bufend: ; 0d20
 
-resb 41
-
-stack: resb 256 ; 0c48
+stack: resb 40 ; 0d20
 	.end: ; 0d48
 
 __0d48 resb 1