Moving line - Emulator Discrepancies

[namco]

I'm trying to program a moving line effect that I seem to have gotten working thanks to Vide but opening it in Para JVE just draws the line as is rather than in the below example:

 

Vide:

https://video.twimg.com/tweet_video/D2uyeyeW0AAMpq4.mp4

 

Code used + Para JVE screenshot:

https://t.co/BQoHme98Uc

 

Would the code I wrote work on a Vectrex like Vide or like Para JVE?

 

[Edit]: I've also noticed that the moving line code I wrote reaches the end of the screen just after the intro bit ends i.e. instead of intro then moving line goes from 2 to the end of the screen, the moving line is already near the end of the screen after the intro. So how would I delay the moving line code from running until after the intro sequence ends?

 

Thanks.

Edited March 28, 2019 by namco

[Malban]

I typed in your code (would have been nicer with a copy and paste!).

And it works both in Vide and ParaJVE alike.

 

But you do not provide enough information!

 

The code cannot be fully seen, dunno where/how you defined "Line_test".

 

Line_test should be in RAM (which I assumed), if you put it into ROM, and enabled Vide to write to ROM, than that would explain the difference.

 

Also - I don't see where you initialize the variable - I guess the answer to that question might lead to the answer of your [edit] question.

 

Also also, I think the proboard forum would be a better place to discuss vectrex coding.

 

Regards

Edited March 28, 2019 by Malban

[namco]

I either provide too much code or too little! XD

 

Anyway, here's the full listing:

Intensity_1F equ $f29d
Intensity_3F equ $f2a1
Intensity_5F equ $f2a5
Moveto_d equ $f312
VIA_t1_cnt_lo equ $d004
Draw_line_d equ $f3df
Wait_recal equ $f192
music1 equ $fd0d
Vec_Misc_Count equ $c823
Delay_3 equ $f56d
Delay_b equ $f57a
Line_test equ 2

	org 0
	
	; intro information start
	db "g GCE 2019",$80 ; g is a copyright sign
	; above MUST start with "g CGE" otherwise it'll just run Minestorm
	; $80 is a string terminator and lower case is for special characters.
	; Uppercase only.
	
	dw music1 ; Pointer to a music structure
	db $f2,$30,$20,-$15 ; height, width, rel y, rel x (from 0,0) of following string
	db "OAOA",$80 ; string format set by above line
	db 0 ; game header finish
	; intro information end
	
main:	
	jsr Wait_recal ; Vectrex BIOS recalibration
	
	;lda #$80 
	;sta VIA_t1_cnt_lo ; Both needed before drawing
	; must set relative position from Wait_recal as cannot use that straight off
	lda #00 ; set y position
	ldb #00 ; set x position
	jsr Moveto_d ; move beam to relative position (from this point it's set at 0,0 due to Wait_recal)
	jsr Intensity_3F ; set beam intensity to 3F
	
	lda #00
	ldb Line_test
	incb
	stb Line_test
	jsr Draw_line_d

	ldb #00
;delay:
;	incb
;	cmpb #255
;	bne delay
	
	bra main
	
	end main

[Malban]

Well.

More or less as I thought.

 

Please read (perhaps again?) my documentation at: http://vide.malban.de/ under the help section, especially the "RAM" thingy (accessed thru the menu).

Line_test equ 2

Places the "Variable" Line_test into the ROM section - actually on the letter "G" (memory address 2) - it should be placed somewhere above $c880 (RAM).

 

The only way to make that work in Vide, is when you enable "write" to ROM. (not sure - perhaps ParaJVE has a switch to allow that too)

(Which I implemented for different reasons - and should under any normal circumstances be switched off, additionally - the usual Vide distribution (unless I have forgotten it),

sets an automatic breakpoint if you try to write to ROM, didn't you get some kind of warning - jump to debugger at some point?).

 

Originaly the EQU (pseudo opcode) statement was ment to define CONSTANTS not labels and not "variables".

The usage to define constant labels like the BIOS locations is simply done because the code of the ROM as source is not available at that point. And the assembler interprets every "number" (even constants, or labels or names) as addresses.

 

Labels should best be defined in the code/ram section of your program.

 

To be utterly clear - Line_test in your context is NOT a variable (in a assembler there are no "variables" - there are always only addresses with additional "meaning")

in that sense, but a constant with the value of "2".

 

If you write

lda #Line_test

 

Than register A will have "2" as a content.

 

If you write

lda Line_test

 

register A will have "G" ($41) as content, because Line_test points to memory address 2, which reads "g GCE"... ( the "G").

 

Regards

Malban

[namco]

It works now!

 

https://twitter.com/namco_/status/1111994920024313856

 

I removed the equ and put the Line_test in RAM space!

 

Thanks.