Hacking DSTwo programming tips

[asiekierka]

.

 

[spinal_cord]

Don't forget the CPU speed settings as calculated by BassAceGold -

speed 0 - 120 mhz
speed 1 - 120 mhz
speed 2 - freezes, couldn't get a clock speed
speed 3 - 144 mhz
speed 4 - 192 mhz
speed 5 - 204 mhz -unstable, freezes in actual use but somehow survived my loop to get a reading
speed 6 - 240 mhz
speed 7 - 264 mhz -unstable, really low performance
speed 8 - 288 mhz
speed 9 - 300 mhz
speed 10 - 336 mhz
speed 11 - 360 mhz
speed 12 - 384 mhz
speed 13 - 396 mhz

Quite handy to know.

 

[Jaylen]

if speeds 2, 5, and 7 are problematic speeds, does the performance actually lower as you go up?
it says that speed 7 has low performance, so does that get inherited as you go up, or by some weird anomaly it actually works again as you go up?

i thought 360Mhz was the official clock speed...can you overclock it?

 

[BassAceGold]

It is just some weird issue with the clock speeds, they do not affect the other speeds. However results could vary on hardware.

360mhz is the most widely used clock speed in the Supercard plugins but 396 is the highest it can go with no issues.

 

[Rydian]

http://dsx86.patrickaalto.com/
This guy's blog has a TON of info on working with the SDK.

 

[Pate]

Sorry about my blog being so disorganized regarding the DSTwo SDK info..

About the CPU speeds, the first level 0 seems to work somewhat strangely. In the SDK demo program (and in BAG's list) the speed is 120MHz, however in my DS2x86 the speed gets set to 60MHz when using speed level 0. I also hacked together a small ASM code to return the current CPU speed as an integer, using the same method as the stupid printf_clock() function uses.

ÂÂÂÂ//------
ÂÂÂÂ// Called from the C code. Get the current CPU speed in MHz.
ÂÂÂÂ//------
ÂÂÂÂ.globalÂÂÂÂGetCPUSpeed
ÂÂÂÂ.typeÂÂÂÂGetCPUSpeed,@function
GetCPUSpeed:
ÂÂÂÂlaÂÂÂÂa0, printf_clockÂÂÂÂÂÂÂÂ// Get address of the function
ÂÂÂÂlhuÂÂÂÂa1, 0(a0)ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ// High halfword of the "_pllout" variable address
ÂÂÂÂlhÂÂÂÂa0, 4(a0)ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ// a0 = signed low halfword of the "_pllout" address
ÂÂÂÂsllÂÂÂÂa1, 16
ÂÂÂÂadduÂÂÂÂa1, a0
ÂÂÂÂlwÂÂÂÂa1, 4(a1)ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ// a1 = _pllout value
ÂÂÂÂluiÂÂÂÂv0, 0x431b
ÂÂÂÂoriÂÂÂÂv0, v0, 0xde83
ÂÂÂÂmultuÂÂÂÂa1, v0ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
ÂÂÂÂmfhiÂÂÂÂv0
ÂÂÂÂsrlÂÂÂÂv0, v0, 0x12
ÂÂÂÂjrÂÂÂÂra

Pate