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Running OCS/AGA/RTG Demos

Arnes Amiga Assembly Course 003

Arne von Boehn
(Apollo Team Member)
Posts 63
22 Jun 2021 16:02


Hello my name is Arne von Boehn ,
   
I'm 14 years old and I love Amiga!
I like Amiga and like coding in assembly
I have written a short Demo in ASMONE Assembly.
It shows a 1280x720 picture
   
here is the video.
 

 


Bastian Zühlke

Posts 23
22 Jun 2021 16:18


Thanks. Since the image file is called wolf.yuv I suppose SAGA supports YUV color decoding natively ?


Gunnar von Boehn
(Apollo Team Member)
Posts 6246
22 Jun 2021 17:14


Yes SAGA support various formats, PLANAR, 8bit, 15bit, 16bit, 24bit, 32bit and also YUV.
 
 

  GFXMODE
    16bit register selecting the screen size and
    the pixelformat for the Chunky plane.
           
 
          +-------+----------+-------------------------------------------+
            | BIT#  | FUNCTION | DESCRIPTION                            |
            +-------+----------+-----------------------------------------+
            | 15.08 | Resolution  | $00                                  |
            |      |              $01 = 320x200                        |
            |      |              $02 = 320x240                        |
            |      |              $03 = 320x256                        |
            |      |              $04 = 640x400                        |
            |      |              $05 = 640x480                        |
            |      |              $06 = 640x512                        |
            |      |              $07 = 960x540                        |
            |      |              $08 = 480x270                        |
            |      |              $09 = 304x224                        |
            |      |              $0A = 1280x720                      |
            |      |              $0B = 640x360                        |
            |      |              $0C = 800x600                        |
            |      |              $0D = 1024x768                      |
            |      |              $0E = 720x576                        |
            |      |              $0F = 848x480                        |
            +-------+----------+-----------------------------------------+
            | 07.00 | Pixelformat | $00                                  |
            |      |              $01 = 8bit (indexed)                |
            |      |              $02 = 16bit R5G6B5                  |
            |      |              $03 = 15bit 1R5G5B5                  |
            |      |              $04 = 24bit R8G8B8                  |
            |      |              $05 = 32bit A8R8G8B8                |
            |      |              $06 = YUV                            |
            |      |              $07 =                                |
            |      |              $08 = PLANAR 1BIT                    |
            |      |              $09 = PLANAR 2BIT                    |
            |      |              $0A = PLANAR 4BIT                    |
            +-------+----------+-----------------------------------------+
 



Stefano Briccolani

Posts 586
22 Jun 2021 17:23


Cool video Arne. Your ASM course for V4 is awesome! I suggest you to paste the source code under your posts so people can easily have a reference without having to take screenshots of the videos.
Thumbs up!!



A1200 Coder

Posts 74
22 Jun 2021 18:02


Interesting, but how do you do hardware scrolling/overscan in these new screenmodes, as the old Amiga hardware had no fixed resolutions, but rather specified with ddfstrt/ddfstop, and visible screen with diwstrt/diwstop? 160 x Y resolution in hardware was also possible under AGA, not sure if it is too useful.


DiscreetFX Studios

Posts 148
22 Jun 2021 20:25


Great video, thanx a bunch.


Kamelito Loveless

Posts 261
23 Jun 2021 11:40


@Gunnar,
So $010A is for Atari ST low res
    $0408 is for Atari ST high res

So there is a missing resolution for mid res for Atari ST right? (640x200) the Pixelformat being $09

Right?



Gunnar von Boehn
(Apollo Team Member)
Posts 6246
23 Jun 2021 11:43


Kamelito Loveless wrote:

@Gunnar,
  So $010A is for Atari ST low res
    $0408 is for Atari ST high res
 
So there is a missing resolution for mid res for Atari ST right? (640x200) the Pixelformat being $09
 
Right?

Hmm good point.
We could add this mode



Kamelito Loveless

Posts 261
15 Feb 2022 21:40


Hi Arne,
There's an error in your code.
you do :

1) move.w $DFF002,DMACON
2) or.w  D0,DMACON

The first line should have been :
move.w $DFF002,D0

Better late than never :)

posts 9