org 0x100

	jmp init

fcb1	equ 0x5C
eof	equ 0x1A
stack	equ 0x10 ; stack size

dumpax	push ax
	push cx
	push dx
	mov dx, ax
	call dmpdx0
	mov al, 0x0A
	call dmpdx3
	mov al, 0x0D
	call dmpdx3
	pop dx
	pop cx
	pop ax
	ret
dmpdx0	mov ah, 0xe
	mov cl, 4
	; this double-call is essentially a 4 times repeating loop
	call dmpdx1
dmpdx1:	call dmpdx2
dmpdx2:	; grab highest nibble from dx
	mov al, dh
	; remove highest nibble from dx
	shl dx, cl
	; shift away second-highest nibble that we accidentally copied
	shr al, cl
	; map 0-9 to ascii codes for '0' to '9'
	add al, 0x30
	; if result is larger than '9', ...
	cmp al, 0x3a
	jl dmpdx3
	; ... add 7 so we continue at 'A'
	add al, 7
dmpdx3:	int 0x10
	ret

free	dw 0 ; free ram size
lncnt	dw 0 ; line count
rdptr	dw 0xFFFF ; infile blk ptr

getc	mov bx, [rdptr]
	cmp bx, 0x80
	jc l01
	mov ah, 0x14
	mov dx, fcb1
	int 0x21
	cmp al, 1
	je l02
	mov bx, 0
l01	mov al, [0x80+bx]
	cmp al, eof
	je l02
	cmp al, 0
	je l02
	cmp al, 0x0A
	jne l01b
	inc word [lncnt]
l01b	inc bx
	mov [rdptr], bx
	jmp l03
l02	mov al, 0x1A
l03	cmp al, eof
	ret

newlin	mov dl, 0x0A
	mov ah, 2
	int 0x21
	mov dl, 0x0D
	int 0x21
	ret

error	mov dl, [bx]
	mov ah, 2
	int 0x21
	inc bx
	cmp dl, 0x20
	jne error
	mov ax, [lncnt]
	call dumpax
	call newlin
	int 0x20

e_eof	db "EOF "
e_dup	db "DUPSYM "

tok1:
s_ws	db " " ; also used for tabs
s_com	db ","
s_obr	db "["
s_cbr	db "]"
s_plu	db "+"
s_min	db "-"

	align 2
tok2:
reg8	db "AL","CL","DL","BL","AH","CH","DH","BH"
reg16	db "AX","CX","DX","BX","SP","BP","SI","DI"
sreg	db "ES","CS","SS","DS"
s_db	db "DB"
s_dw	db "DW"

tok3:
s_org	db "ORG"
s_equ	db "EQU"

	; TODO: parse a line into wordlist of tokens and ptrs to strings
rline:	ret

	; clear symbol table
main	mov byte [init], 0
	call rline
	int 0x20

	align 16

	; stuff behind here gets overwritten
	; by symbol table and program data

init	mov ax, [6]
	mov dx, sp
	sub dx, stack
	cmp ax, dx
	jc il01
	mov ax, dx
il01	sub ax, init
	shr ax, 1
	and ax, 0xFFF0
	mov [free], ax
	; open input file
	mov ah, 0x0F
	mov dx, fcb1
	int 0x21
	mov bx, e_op
	test al, al
	jnz error
	jmp main

e_op	db "NOFILE "