My first experiment with the DSP-1.
Okay, the relation between the decreasing of the 1s timer and the coin counter might not be fully optimal - since my formula for it isn't -, but focus on the 10s counter.
Basically this is a simple multiplication - but the DSP-1 can do much more. It is used in pseudo-3D position calculation and angle calculation, too. Games such as Pilotwings make heavy use of these functions.
This type of multiplication is still better than $4202 and $4203 in two aspects:
- 1. The multiplicand and multiplier have four digits, of which the lower byte can be told to form some sort of fraction. The actual formula is :
A x B >> 15 = Result.
>> 15 instead of >> 16, probably, to get more accurate results. In this example I just LSR'd the result 1 time extra.
Either way, this concludes that the DSP-1 hands out
much more accurate results than $4216/$4217 do.
- 2. Absolutely NO NOPs are needed for multiplication. I repeat,
NO NOPs!.
The DSP-1 runs on 7.68 MHz (2-2.5 times as fast as the SNES CPU!) which means actions are done way faster. I wonder if SNES auto-halts for the DSP-1 to give a sign when it's done, or if NOPs are still needed in the case of actions that require a large amount of cycles, such as projector calculation.
Moral of the story: SNES Dev book2.pdf wins.
Now we're at the topic of pseudo-3D, why not show you my current Mode 7 level:
Edit: Also the stuff left of Mario is an island. Please don't look too much at it - it's terrifying. I'm gonna make new land tiles anyway.
--------> Don't follow "Find Roy's Dignity",
my hack. Because it's pretty outdated.
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