Friday, February 26, 2016

Time Traveler supports a Pioneer player??

This may be common knowledge to most people, but I just made a startling discovery as I delved deeper into the Time Traveler ROM.

It all started innocently enough.  I was finding the function that issues the "still step forward" command:

I converted the line at d37e:0893 from being a constant value of 0xd9d to an enumeration (StepFwdArr) to make it easier to read.  And I noticed that this function at d37e:87b will either send the "still step forward" command by calling the function at D31C6_SomeSendByteToLDP (the name I  picked in my screenshot) or it will load in the array at 0xd9f and call sub_D33F1.  I found this... odd.  Why would it either call the LDP or do something unrelated?  I decided that 0xd9f was close enough to 0xd9d that they might be related.  So I jumped to that location in the ROM:

I thought "Huh, that's weird.  The stuff at d9f looks like some ascii with a carriage return termination."  And I thought "Why would that be in this ROM?  It doesn't have a need for carriage return terminating any string."

Having no answer at this point, I decided to look for other commands that called D31C6_SomeSendByteToLDP.  I found here:

And I checked to see what 0xDa3 pointed to and it was the 0x2C command which is "still step reverse".  And I noticed a similar pattern with this method.  It either sends to the LDP or else is calls this unknown D33F1 function which uses a pointer at 0xda5.  They definitely look related.

I looked closer...

Yes, 0xda3 has the 0x2C command... and then 0xda5 has that same ASCII array with a carriage return (0x0D) terminator!

And then I had the "ah ha" moment.

The 0xda5 stuff is commands for a Pioneer LD-V8000 (or similar) kind of player!!

So Time Traveler... has code in it... to control either a sony LDP-1450... or a Pioneer LD-V8000!  I couldn't believe it!  And I had this awesome feeling of "Whoa" once I figured it out :)

SF means... step forward... SR means.. step reverse.  I haven't confirmed this.. but it has to be right, dangit.  It has to! :)

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