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reading pci cfg_data register on MPC8544

Question asked by tonykleman on Sep 11, 2014
Latest reply on Sep 11, 2014 by tonykleman


What is the method in assembly for reading a PCI register out to memory?   I load the address of the PCI register CFG_DATA into GPR R1 and then try to use lwz to do an indirect read of that address.

lis r1,0xF000

ori r1,r1,0x8004          # the address of CFG_DATA into r1

lwz r3,0(R1)               # the value of CFG_DATA copied into r3


But r3 never gets updated with this code.