You can try to reverse the base os timing Interrupt settings or the clock settings for the can/serial divider registers.
With that you can recalculate the clock frequency / external osc.
Take formula from Datasheet for those registers and evaluate the formula to the term you need. Mostly fOsc or fCpu. Insert register values loaded in binary and you should have it.
Again: no way to get the SY_* directly.
Good luck
Im not sure this way is safe, but i found the "SSC Baudrate Register".
I hope with this register i can get the safe cpu clock.
-- Cutted ASM Code
mov r12, #4637h
mov r13, #13h
mov r14, #2
mov word_F0B4, r13
-- Notes from me ( values are in hex )
13 = 40MHz
0F = 32MHz
0B = 24MHz
09 = 20MHz
If someone can correct me or have better idea, please tell me.
Edit:
Seems values are very near,
32000KHz / 0Fh = 855h
855h x 13 = 40527 KHz
855h x 0F = 31995 KHz
855h x 0B = 23463 KHz
855h x 09 = 19197 KHz