HELLO-WORLD-ATARI-ASSEMBLER
--------------------------------------------------------------------------------------------------
TOOL: 		ATARI SynAssembler {ATARI-800XL}
Language: 	SynAssembler by Synapse 
Extra:		-
Author: 	Misel Zivanovic
Note:		(C) 18th DEC 2025 - www.lived.ch, mzretro.ch
---------------------------------------------------------------------------------------------------

I almost forgot this mandatory one.
The most difficult thing was to get the screen address here.
So what i did was POKING around until something appeared on the screen!
Now tell me how clever that was! Haha...

Don't think how this code requires any extra explanations.

00010  .OR $3000
00020  .LI OFF
00030  LDY #0
00040 LOOP LDA HELLO,X
00050  STA $9C4D,X		
00060  INX
00070  CPX #12
00080  BNE LOOP
00090 GO LDA $2FC
00100  CMP #$0C   ;ENTER TO QUIT
00110  BEQ QUIT
00120  JMP GO
00130 QUIT RTS
00140 HELLO .AT "HELLO WORLD!"

ASM 		{and press ENTER to assemble}
 
RUN $3000 	{and press ENTER to execute}

---------------------------------------------------------------------------------------------------

23:58 18.12.2025
Couldn't resist not to take a look at the ATARI SCREEN START ADDRESS mystery and see there, that 
really depends on many things!

	------------------------------------------------------------------------------	
	With ATARI DOS 2.5
	and SynAssembler inserted, the SCREEN START ADRESS was at location 40000
	In other words: lda #20: sta $9c40 brought @ on the screen, left upper corner.
	------------------------------------------------------------------------------	

	------------------------------------------------------------------------------
	With Turbo-BASIC 1.5 XL {.crt image}
	The SCREEN START ADDRESS moved to another location, namely 48192, hex $bc40
	Meaning: lda #32: sta $bc40 is now to use to show @ in the left upper corner
	------------------------------------------------------------------------------


	CONCLUSION:
	I did not try more, but it is obvious how the START ADDRESS of the SCREEN
	depends on what's inserted and used with ATARI-800XL and also how much memory
	your ATARI has!

	And that was now only for the GRAPHICS 0 {TEXT}
	It is getting to be interesting!	

	The addresses 88 and 89 were used here to find out the correct start address {SCREEN}


DISPLAY LIST:

`	I want to explore DisplayList as next and i already smell the problems! Haha...
	There is a magic formula existing to get the start address of DL:

	"You can also find the address of the DL by
	PEEKing one byte above the top of free memory:"

	PRINT PEEK(741) + PEEK(742) * 256 + l.
	
	When i do that, i get 48160

	Now i just need to find out what to put in there to get some results!
	And since it is a DisplayList it will sure have more than one entry!

	WELL, WE INDEED LEARNED SOMETHING!