Line prefixes for listings

edlin.asm

@@ -49,6 +49,18 @@ int_ctrl_break equ 0x23
 %macro addw 2
 	db 0x03, 0xc0 + 8 * %1 + %2
 %endmacro
+%macro adcb 2
+	db 0x12, 0xc0 + 8 * %1 + %2
+%endmacro
+%macro cmpw 2
+	db 0x3b, 0xc0 + 8 * %1 + %2
+%endmacro
+%macro movw 2
+	db 0x8b, 0xc0 + 8 * %1 + %2
+%endmacro
+%macro movb 2
+	db 0x8a, 0xc0 + 8 * %1 + %2
+%endmacro
 %macro orw 2
 	db 0x0b, 0xc0 + 8 * %1 + %2
 %endmacro
@@ -58,15 +70,12 @@ int_ctrl_break equ 0x23
 %macro subw 2
 	db 0x2b, 0xc0 + 8 * %1 + %2
 %endmacro
+%macro subb 2
+	db 0x2a, 0xc0 + 8 * %1 + %2
+%endmacro
 %macro xorw 2
 	db 0x33, 0xc0 + 8 * %1 + %2
 %endmacro
-%macro cmpw 2
-	db 0x3b, 0xc0 + 8 * %1 + %2
-%endmacro
-%macro movw 2
-	db 0x8b, 0xc0 + 8 * %1 + %2
-%endmacro
 
 ; Sign extended byte to byte
 %macro cmpb_addr_ext 2
@@ -223,7 +232,7 @@ initialize_editor: ; 0240
 	test byte [new_file_flag], 0xff
 	jnz editor_mainloop
 
-	call __0370
+	call command_a
 
 editor_mainloop: ; 0273
 	mov sp, stack.end
@@ -278,6 +287,8 @@ editor_mainloop: ; 0273
 	repne scasb
 	jne print_entry_error ; Not found
 
+	; CX counts down, so first entry matching gives cx=9, second cx=8, etc.
+
 	movw r_bx, r_cx
 	mov ax, [__0a82]
 	orw r_ax, r_ax
@@ -366,17 +377,19 @@ parse_line_specifier: ; 02f9
 		ret
 
 commands db 'QWASRDLIE', 13 ; 0340
+
+; This is reversed in regards to commands table due to implementation of matching
 command_addresses: ; 034a
-	dw command_q ; Q
-	dw command_w ; W
-	dw command_a ; A
-	dw command_s ; S
-	dw command_r ; R
-	dw command_d ; D
-	dw command_l ; L
-	dw __0370 ; I
-	dw command_e ; E
 	dw command_cr ; CR
+	dw command_e ; E
+	dw command_i ; I
+	dw command_l ; L
+	dw command_d ; D
+	dw command_r ; R
+	dw command_s ; S
+	dw command_a ; A
+	dw command_w ; W
+	dw command_q ; Q
 
 find_file_end_char: ; 035e
 	push di
@@ -397,7 +410,7 @@ find_file_end_char: ; 035e
 __036d:
 	jmp print_eof_str
 
-__0370:
+command_a:
 	test byte [new_file_flag], 0xff
 	jnz __036d
 
@@ -487,7 +500,7 @@ __0406:
 _trampoline_oom_1: ; 0414
 	jmp oom
 
-command_e: ; 0417
+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
@@ -557,51 +570,81 @@ db 0x42 ; 04AC inc dx
 db 0x3B, 0xDA ; 04AD cmp bx,dx
 db 0x75, 0xF7 ; 04AF jnz 0x4a8
 db 0xC3 ; 04B1 ret
-db 0x53 ; 04B2 push bx
-db 0xB0, 0x20 ; 04B3 mov al,0x20
-db 0xE8, 0x6C, 0x04 ; 04B5 call 0x924
-db 0xE8, 0x13, 0x00 ; 04B8 call 0x4ce
-db 0xB0, 0x3A ; 04BB mov al,0x3a
-db 0xE8, 0x64, 0x04 ; 04BD call 0x924
-db 0xB0, 0x2A ; 04C0 mov al,0x2a
-db 0x5B ; 04C2 pop bx
-db 0x3B, 0x1E, 0x90, 0x0A ; 04C3 cmp bx,[0xa90]
-db 0x74, 0x02 ; 04C7 jz 0x4cb
-db 0xB0, 0x20 ; 04C9 mov al,0x20
-db 0xE9, 0x56, 0x04 ; 04CB jmp 0x924
-db 0x33, 0xC0 ; 04CE xor ax,ax
-db 0x8A, 0xD0 ; 04D0 mov dl,al
-db 0xB9, 0x10, 0x00 ; 04D2 mov cx,0x10
-db 0xD1, 0xE3 ; 04D5 shl bx,1
-db 0x12, 0xC0 ; 04D7 adc al,al
-db 0x27 ; 04D9 daa
-db 0x86, 0xC4 ; 04DA xchg al,ah
-db 0x12, 0xC0 ; 04DC adc al,al
-db 0x27 ; 04DE daa
-db 0x86, 0xC4 ; 04DF xchg al,ah
-db 0x12, 0xD2 ; 04E1 adc dl,dl
-db 0xE2, 0xF0 ; 04E3 loop 0x4d5
-db 0xB3, 0x10 ; 04E5 mov bl,0x10
-db 0x92 ; 04E7 xchg ax,dx
-db 0xE8, 0x16, 0x00 ; 04E8 call 0x501
-db 0x8A, 0xC6 ; 04EB mov al,dh
-db 0xE8, 0x02, 0x00 ; 04ED call 0x4f2
-db 0x8A, 0xC2 ; 04F0 mov al,dl
-db 0x8A, 0xF0 ; 04F2 mov dh,al
-db 0xD0, 0xE8 ; 04F4 shr al,1
-db 0xD0, 0xE8 ; 04F6 shr al,1
-db 0xD0, 0xE8 ; 04F8 shr al,1
-db 0xD0, 0xE8 ; 04FA shr al,1
-db 0xE8, 0x02, 0x00 ; 04FC call 0x501
-db 0x8A, 0xC6 ; 04FF mov al,dh
-db 0x24, 0x0F ; 0501 and al,0xf
-db 0x74, 0x02 ; 0503 jz 0x507
-db 0xB3, 0x00 ; 0505 mov bl,0x0
-db 0x04, 0x30 ; 0507 add al,0x30
-db 0x2A, 0xC3 ; 0509 sub al,bl
-db 0xE9, 0x16, 0x04 ; 050B jmp 0x924
 
-command_s: ; 050e
+print_line_prefix: ; 04b2
+	push bx
+
+	mov al, ' '
+	call print_char
+	call print_number
+	mov al, ':'
+	call print_char
+	mov al, '*'
+
+	pop bx
+
+	cmp bx, [current_line]
+	je .end
+	mov al, ' '
+
+	.end: jmp print_char
+
+print_number: ; 04ce
+	; Input in bx
+
+	; Zero out the 5-digit BCD number
+	xorw r_ax, r_ax
+	movb r_dl, r_al
+
+	mov cx, 16
+	.loop: ; 04d5
+		shl bx, 1
+
+		; Double al (bcd), and add in carry out from the shift
+		adcb r_al, r_al
+		daa
+		; Double ah (bcd) and propagate carry
+		xchg al, ah
+		adcb r_al, r_al
+		daa
+		xchg al, ah
+		; Double dl (bcd) and propagate carry
+		adcb r_dl, r_dl
+
+		loop .loop
+
+print_bcd:
+	; Prints a 5-digit BCD number stored in DX:AX as such (x is ignored)
+	; dh dl ah al
+	; xx x1 23 45
+	mov bl, '0' - ' ' ; If value is zero, replace with space
+
+	xchg ax, dx
+	; First digit, low nybble of dl
+	call print_bcd_digit
+	; Next two digits, ah
+	movb r_al, r_dh
+	call print_bcd_byte
+	; Final two digits, al
+	movb r_al, r_dl
+
+print_bcd_byte: ; 04f2
+	movb r_dh, r_al
+	times 4 shr al, 1
+	call print_bcd_digit
+	movb r_al, r_dh
+
+print_bcd_digit: ; 0501
+	and al, 0xf
+	jz .to_ascii
+	mov bl, 0 ; Only apply replacement to zero values
+
+	.to_ascii:
+	add al, '0'
+	subb r_al, r_bl
+	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
@@ -668,7 +711,7 @@ db 0xAA ; 0591 stosb
 db 0xC3 ; 0592 ret
 db 0xE9, 0xC9, 0x00 ; 0593 jmp 0x65f
 
-command_d: ; 0596
+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]
@@ -725,7 +768,7 @@ db 0xC3 ; 0621 ret
 db 0xBA, 0x21, 0x0A ; 0622 mov dx,0xa21
 db 0xEB, 0x3B ; 0625 jmp short 0x662
 
-command_l: ; 0627
+command_s: ; 0627
 db 0xE8, 0x6C, 0x00 ; 0627 call 0x696
 db 0x75, 0x33 ; 062A jnz 0x65f
 db 0x8B, 0x1E, 0x8A, 0x0A ; 062C mov bx,[0xa8a]
@@ -841,7 +884,7 @@ db 0xAA ; 074A stosb
 db 0x41 ; 074B inc cx
 db 0xEB, 0xF3 ; 074C jmp short 0x741
 
-command_r: ; 074e
+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
@@ -866,7 +909,7 @@ db 0x33, 0xC9 ; 077E xor cx,cx
 db 0xEB, 0x55 ; 0780 jmp short 0x7d7
 db 0xE9, 0x6A, 0xFB ; 0782 jmp 0x2ef
 
-command_q: ; 0785
+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
@@ -931,7 +974,7 @@ oom: ; 080c
 	int 0x21
 	jmp editor_mainloop
 
-command_a: ; 08cd
+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
@@ -994,7 +1037,7 @@ db 0x4F ; 089E dec di
 db 0x89, 0x3E, 0x9A, 0x0A ; 089F mov [0xa9a],di
 db 0xE9, 0xCD, 0xF9 ; 08A3 jmp 0x273
 
-command_cr: ; 08a6
+command_q: ; 08a6
 db 0xBA, 0x45, 0x0A ; 08A6 mov dx,0xa45
 db 0xB4, 0x09 ; 08A9 mov ah,0x9
 db 0xCD, 0x21 ; 08AB int 0x21
@@ -1012,7 +1055,7 @@ 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
 
-command_w: ; 08cd
+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