mempack commands to the n64 controllers

while i'm personally unaware of exatcly how the controllers send the data from the memory packs back and forth, i'd expect it to be where the console asks for a certain offset and it sends a few byte (1 2 or 4 i'd guess) rather than sending the entire copy.

i was wondering if someone could point me to part of the source for some of the opensource emulators where the mempacks get emulated, maybe i can get more information about how to dump the mempacks through the controllers using either the same circuit as http://home.t-online.de/home/stephan.hans/n64.htm or one slightly modified to work well enough.

ok i've gotten a pretty good idea of how it sends it back, it'll take a modified circuit to do this, need 32 bytes of storage apparently, might look into making a completely different circuit later for this, but i still dont fully understand what gets sent to the controller to read the mempack

so far i believe it is something like this

0x03 (One byte command to read the control pack)
0x?? (i think there is something supposed to go here
0xAAAA (address where you want to read 32 bytes from?)

ok it sends 32 bytes i believe, and the command works like this

0x03 0x80 0x01 (controller sends 32 bytes back containing the checksum of the mempack!)

0x03 0xAB 0xCD last two bytes are the address and the controller sends the encrypted 32 bytes back, to decrypt them you XOR them with the checksum bytes.

my question is why goto all that trouble to just send data like that?