| ------------------------------------------------------------------------------
| vputcv.s -- store a character and attributes in video RAM
| Version 1 -- 1988-10-05 -- D.N. Lynx Crowe
| (c) Copyright 1988 -- D.N. Lynx Crowe
| ------------------------------------------------------------------------------

|	vputcv(adr, row, col, chr, atr, cols)
|	unsigned int *adr, row, col, chr, atr, cols;

|		Stores character 'chr' at ('row', 'col') in the
|		full attribute text object at 'adr' with
|		attribute value 'atr' using a line length of 'len'.
| ------------------------------------------------------------------------------

		.text

		.xdef	vputcv

P_ADR		=	8
P_ROW		=	12
P_COL		=	14
P_CHR		=	16
P_ATR		=	18
P_LEN		=	20

		.page

vputcv:		link	a6,#0		| Link stack frame pointer
		move.w	P_ROW(a6),d0	| Get row
		mulu	P_LEN(a6),d0	| Multiply by len
		clr.l	d1		| Clear out d1
		move.w	P_COL(a6),d1	| Get col
		add.l	d1,d0		| Add col into d0 to get char. #
		move.l	d0,d1		| Develop cw = (cn/2)*6 in d1
		andi.l	#0xFFFFFFFE,d1	| ...
		move.l	d1,d2		| ...
		add.l	d1,d1		| ...
		add.l	d2,d1		| ...
		add.l	P_ADR(a6),d1	| Add sbase to cw
		movea.l	d1,a0		| a0 points at the word with the char.
		btst.l	#0,d0		| Odd char. location ?
		bne	vputcv1		| Jump if so

		move.w	P_CHR(a6),d0	| Get chr
		andi.w	#0x00FF,d0	| Mask off garbage bits
		move.w	(a0),d1		| Get word from video RAM
		andi.w	#0xFF00,d1	| Mask off old even character
		or.w	d0,d1		| OR in the new character
		move.w	d1,(a0)+	| Store the updated word in video RAM
		bra	vputcvx		| Done -- go return to caller

vputcv1:	move.w	P_CHR(a6),d0	| Get chr
		lsl.w	#8,d0		| Shift to high (odd) byte
		move.w	(a0),d1		| Get word from video RAM
		andi.w	#0x00FF,d1	| Mask off old odd character
		or.w	d0,d1		| OR in the new character
		move.w	d1,(a0)+	| Store the updated word in video RAM
		addq.l	#2,a0		| Point at the attribute word

vputcvx:	move.w	P_ATR(a6),(a0)	| Store new attributes in video RAM
		unlk	a6		| Unlink the stack frame
		rts			| Return to caller

		.end