DMA routine for HuC

[tomaitheous]

***UPDATE***

I updated the routine and zip file. The array was causing the compiler to bloat and slowdown the code - fixed.

***CAUTION***
Don't use this routine if the number of bytes is more than 32 and the display is on. It will delay all interrupts!

 
[original]
Here's a small DMA routine for use with HuC. The PCE has a total of five DMA instructions - I actually didn't notice a fifth one until today

I made the interface C friendly. The instructions on it use are inside the DMA_RTN.h file. The destination can be anywhere - VDC, VCE, memory, SGX data port($0012), etc. You're not limited to global variables when assigning the parameters, but it's prefered for speed when used in loops.

 The speed of the DMA is at ASM level since it's a block transfer instruction, but the arguement assigning is handled via the HuC compiler for flexibility and ease of use. If there is a need for a fast parameter setup in clock cycle resitrictive loops, let me know and I'll see what I can come up with.

Here's the file - http://pcedev.net/HuC/Dma_rtn.zip

 I'll post it on the magicengine forums, although the dev section looks to be at a crawl at the moment.


-Rich

[tomaitheous]

[Edit]
The DMA routine does not load BANK that contains the specific DATA pointed by routine.

For bandaid fix, do a

Code:

var=source_data[x]

each time in HuC to prime the bank, before using START_DMA() - until I can update the code.

If you use DMA_SRC=DATA right before START_DMA, you should be ok as this should cause HuC to load the corrosponding bank inwhich the DATA is pointed to.


[Edit]#2
DMA_SRC=DATA does not trigger the BANK switch - probably because it's a #define instead of a var. Use a global var to trigger the bank switch,i.e. force_bank=data[0]; .

[Inpuptacuts]

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[Keranu]

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[Paranoia Dragon]

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How can I apply this wonderful code with ASM #48328@# & the Fibinache routine?

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