English Amiga Board - View Single Post - Strange behavior when using blit queue in copper list

Photon · 27 January 2018, 22:39

I have to disagree.

I'm addressing intent, and you're addressing hardware implementation/emulation accuracy. Two sides of the same coin, yet worlds apart. Ends of a spectrum.

The chips stay the same and do what you tell them, so it's about 100000 times more likely (rough estimate) that the coders are writing code that doesn't express their intent.

HRM is certainly accurate and complete enough to allow a relatively experienced hardware programmer (whether new to Amiga or not) to code a Copper list that blits, and a font writer is beginner stuff and the code worked and you fixed the emulation.

I have to wag my finger and say "tsk, tsk!" at that you say you don't like "better do this just to be safe", but then suggest changing the order of register writes for no good reason and haven't protested against "try this" things such as waiting an extra line, double blit waits in Copper lists, etc. (Which I'm quick to do now!

)

I normally refuse to help if no code is posted, but I still wanted to help.

Now I used my rules and they ruled out the blits, and on the HRM page I linked it says that the blitter WAIT is a normal WAIT with an AND condition provided by bit 15. HPOS below $07 as you know is on the previous line and will fail >= comparisons on the raster.

$0001,$0000 is not a correct WAIT instruction, and $0007,$7ffe is a correct Copper Blit WAIT.

27 January 2018, 22:39	#36
Photon Moderator Join Date: Nov 2004 Location: Eksjö / Sweden Posts: 5,610	I have to disagree. I'm addressing intent, and you're addressing hardware implementation/emulation accuracy. Two sides of the same coin, yet worlds apart. Ends of a spectrum. The chips stay the same and do what you tell them, so it's about 100000 times more likely (rough estimate) that the coders are writing code that doesn't express their intent. HRM is certainly accurate and complete enough to allow a relatively experienced hardware programmer (whether new to Amiga or not) to code a Copper list that blits, and a font writer is beginner stuff and the code worked and you fixed the emulation. I have to wag my finger and say "tsk, tsk!" at that you say you don't like "better do this just to be safe", but then suggest changing the order of register writes for no good reason and haven't protested against "try this" things such as waiting an extra line, double blit waits in Copper lists, etc. (Which I'm quick to do now! ) I normally refuse to help if no code is posted, but I still wanted to help. Now I used my rules and they ruled out the blits, and on the HRM page I linked it says that the blitter WAIT is a normal WAIT with an AND condition provided by bit 15. HPOS below $07 as you know is on the previous line and will fail >= comparisons on the raster. $0001,$0000 is not a correct WAIT instruction, and $0007,$7ffe is a correct Copper Blit WAIT.