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JLP Acceleration vs RAM vs FLASH


wavemotion

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This stated here where I had some confusion on the config vars for JLP use:

  

1 hour ago, mr_me said:

Ideally, jlp ram and jlp acceleration activation should be separated. That's because it's possible for a game on a jlp cartridge to to use it's ram but not the hardware acceleration functions.  Since such a game could possibly run on cartridges and emulators that don't support jlp hardware acceleration, your work around is reasonable.

Okay... I almost get it...  :)

 

According to @intvnut, he documented the following uses of the flags here on the forums:

 

 

; To enable JLP accelerators and RAM only CFG_VAR "jlp" = 1 ;

; To enable JLP accelerators and flash save area CFG_VAR "jlp" = 3 CFG_VAR "jlp_flash" = 4 ; change 4 to however many 1.5K byte flash sectors you need

 

But it goes a bit more in-depth in the Locutus guide in the cfg vars section:

image.thumb.png.c624768c0b357bf857be78403052dfc8.png

image.thumb.png.2f497b268baa7b3c5a5bc29e0731a2bd.png

 

As near as I can tell, you always get RAM support with Acceleration support but there are clearly games that utilize RAM and not acceleration functions.. And for A-F, I see jlp=1 which shouldn't allow flash support but it clearly uses it (and has jlpflash = 16 ... notice the missing underscore).

 

Right now, with Nintellivision, I treat jlp=1 and jlp=3 as basically the same (Acceleration enabled and RAM enabled) and look to either jlpflash or jlp_flash as the indicator for flash support. 

 

I've also noticed that most of the jlp_flash/jlpflash settings are just some default value... I see jlpflash=100 for TNT Cowboy but it never appears to erase/write past 32K (and it only appears to be using a fraction of that for save data).

 

Is there a better table explaining jlp values vs jlp_flash/jlpflash values?  I looked at the JLP Programmers View pdf which is great technical information but didn't go into more detail on the config vars.

 

 

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@mr_me provides this documentation from jzintv which is rather more concrete and doesn't tie Accelerator Functions to RAM. 

 

http://spatula-city.org/~im14u2c/intv/jzintv/doc/utilities/as1600.txt 

 

The jlp_accel value (aka. jlp) takes on one of 4 values:

    0       JLP disabled
    1       JLP accelerators enabled at reset, no JLP flash
    2       JLP accelerators disabled at reset, JLP flash storage present
    3       JLP accelerators enabled at reset, JLP flash storage present

For jlp_accel >= 2, the jlp_flash value should be non-zero.  If missing,
it will take on a minimum value of 4.  If set to 0, jlp_flash support will
be disabled.

 

I still see games that use jlp=1 and then define jlp_flash (in the case of A-F, they typo it to jlpflash and although the game does use JLP Flash, proper interpretation would disable it).

 

I also see games that use a minimum flash size of 64h (=100d) which must be some kind of default for some toolset.  I'm almost to the point of ignoring it... this is 150K of storage which is fine for a PC but takes time on an embedded emulator on the DS - and when I look at what actually gets written, it's often just a dozen bytes or so.  

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On 8/14/2023 at 11:52 AM, llabnip said:

...And for A-F, I see jlp=1 which shouldn't allow flash support but it clearly uses it (and has jlpflash = 16 ... notice the missing underscore).

 

Right now, with Nintellivision, I treat jlp=1 and jlp=3 as basically the same (Acceleration enabled and RAM enabled) and look to either jlpflash or jlp_flash as the indicator for flash support. 

...

Looks like bin2luigi does the same thing, and I presume Jzintv as well.  The following is from the luigi documentation.

 

"bin2luigi  upgrades  jlp_accel  = 1;  jlp_flash  > 0 to  jlp_accel  = 3 when encoding a LUIGI."

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