Homebrew Challenge: Improve PicodriveDS code

[xonn]

Seems to work great!
Any chance you can make a PR for PicoDriveTWL featuring your changes?

Thanks!
Code was updated and now it uses PicodriveTWL version but not depends on TWL, can be executed from R4 card or through TWLMenu.

 

[Shadow#1]

Thanks!
Code was updated and now it uses PicodriveTWL version but not depends on TWL, can be executed from R4 card or through TWLMenu.

Since it has @Robz8 approval about time for a .cia?

 

[Coto]

Thanks @Coto for your message. It's really instructive.
New changes made. Please check emulator and post your thoughts

Another trick I remember from the 90's (the last good decade in systems engineering R&D by far), on slower systems like the Nintendo DS, if you look at the hardware design, Nintendo thought very well how to maximize profits while retaining high performance on very specific hardware pieces.

NintendoDS Programming notes:
Cons:
1) Yes, 66mhz ARM9 is slow to do realtime decoding
2) EWRAM sharing the ARM9 and ARM7 experimental design

Pros:
Data TCM and Instruction TCM can be exploited to use constructed LUTs. Such as calculating color coefficients, lights, or samples of any kind. The barrel shifter can then (through an ALU opcode) work with these tables... from TCM memory!
This allows to keep up with very decent speeds when, decoding a frame of some sort (video/audio).

This step usually is an optimization out of a very slow, but working software implementation.

 

[ElectricJelly]

Having some trouble. Do the MegaDrive ROM files need to be in a specific format? Mine are in the right place as MDs, but are not showing up in TWiLight Menu. Also, does the NDS file need to be in a specific location and\or renamed?

 

[Pk11]

Having some trouble. Do the MegaDrive ROM files need to be in a specific format? Mine are in the right place as MDs, but are not showing up in TWiLight Menu. Also, does the NDS file need to be in a specific location and\or renamed?

I think TWiLight only shows ".gen" files, you can simply rename them to change. TWiLight includes a version of PicoDriveDS at "sd:/_nds/TWiLightMenu/emulators/PicoDriveTWL.nds" so if you want to use this version with TWiLight you'll either need to replace that file with it or launch this directly and load the rom from within it.

 

[ElectricJelly]

Thanks Pk11.

 

[Turesy]

Also, should the MDS file be located in a specific location?