screen 8 smooth horizontal scrolling

Under dos2 the files cannot stay in subdirectories or the CPM libraries will fail finding the data

@ARTRAG

There are a lot of oddities regarding the R#18. MSX MAP already lists some of them:

http://map.grauw.nl/articles/vdp_guide.php

If you find any new one, please contribute to the article. :)

New version! I fixed the blue issue in the palette of screen 8
Now colors look closer to the original

In version 2 of screen8_2011_02_22.rar I've tried to enable sprites before moving r#18

At TNI MAP
http://map.grauw.nl/articles/vdp_guide.php
it says:
Q: r#18 in combination with VDP commands corrupts VRAM?

A: Yes. This issue only occurs when you have the sprites (or screen) disabled. If you use the screen position adjust register while executing a copy command and with sprites disabled, it will corrupt the byte the VDP command is currently processing. So, if that is the case, you should wait with setting r#18 until the VDP’s CE bit indicates the current command is finished.

The current code makes sure sprites are enabled before moving r#18 but still few dots appear in the copies....
Actually this does not seem to fix the glitces....

the critical code is in main.c and is

vblank:
	ld	a,(RG8SAV)		; enable sprites
	out	(0x99),a
	ld	a,8+128
	out	(0x99),a

	ld	a,(_displaypage)
	add a,a ;x32
	add a,a
	add a,a
	add a,a
	add a,a
	add a,31
	out (0x99),a
	ld a,2+128
	out (0x99),a
	
	ld	a,(_xoffset)
	add	a,-8
	and	0Fh
	out	(099h),a
	ld	a,18+128
	out	(099h),a
....

and also

lint:					
	xor	a
	out	(099h),a
	ld	a,18+128
	out	(099h),a		; setadjust 0,0
	
	ld a,31
	out (0x99),a
	ld a,2+128
	out (0x99),a		; scorebar in page 0

	ld	a,(RG8SAV)
	or	2				; disable sprites
	out	(0x99),a
	ld	a,8+128
	out	(0x99),a
....

Where lint is called at line 144 when sprites are active: sprites are disactivared AFTER R#18 is set

vblank is called at line 192: here we wait some cycles after re-enabling sprites before setting R#18

Any suggestion?
https://sites.google.com/site/testmsx/screen-8-smooth-horizontal-scrolling/screen8_2011_02_22.rar?attredirects=0&d=1

Under dos2 the files cannot stay in subdirectories or the CPM libraries will fail finding the data

Bullshit warning!

(Or at least good explanation needed. I don't know how this could happen.)

hallo ARTRAG ,
does set adjust (0,0) always happen in the same point on screen or there may be a delay dependent on some condition ( JP C,.... / JP Z,.. ) ?
have you tried putting some NOPs before set adjust (0,0) in order to be out of some critical regions ?
( during horizontal retrace it takes about 16microsec right border - right erase time -sync signal -left erase time - left border )

Both routines are called by a very simple interrupt handler that tries to discriminate between the two sources of interrupt:

	
_scroll:
	push	af
	
	xor	a 			; read S#0
	out (0x99),a
	ld a,128+15
	out (0x99),a
	in	a,(0x99)
	rlca
	jp	c,vblank
	
	ld a,1 			; read S#1
	out (0x99),a
	ld a,128+15
	out (0x99),a
	in a,(0x99)
	rra
	jp	c,lint	
	
	pop	af
	ret				; ?? what the hell I'm doing here ??

Actually Vblank interrupt could be delayed by the execution of some large loops under DI/EI that I need in lint for sending VDP commands

So lint sends VDP commands, vblank can interrupt it whne the former enables interrupts

In the current code nothing delayes liint as the main is always with EI enabled