; IN	DS:SI	remaining unparsed string
	;	CS:DI	error message
parse_error:
	push si
	mov si, di
	call putcs
	mov al, ':'
	call putc
	mov al, ' '
	call putc
	pop si
	call putds
	jmp crlf

eat_whitespace:
	; peek on next char
	mov al, [si]
	; ES := CS
	push es
	push cs
	pop es
	; string search
	mov di, .chars
	mov cx, 4
	scasb
	; restore bss segment
	pop es
	jne .ret
	inc si
	jmp eat_whitespace
.chars:	db 0x09, 0x0A, 0x0D, 0x20
.ret:	ret

	; IN:	DS:SI	string to read
	; OUT:	CF set	if no match
	;	BX	register number * 2 if CF clear
eat_register:
	push si
	push es
	lodsw
	and ax, 0xDFDF
	; ES := CS
	push cs
	pop es
	mov di, rnames
	mov cx, 14
	repne scasw
	pop es
	jne .fail
	pop bx
	mov bx, di
	sub bx, (rnames+2)
	clc
	ret
.fail:	pop si
	stc
	ret
.emsg:	db "Not a register name", 0