Accessing the configuration registers

[Anil Kumar S R]

Hi,
  I am using a PCI-ISA bridge, I want to read the Local Configuration 
  Registers.
  There are two ways to do :
  1. I/O mapped
  2. Memory mapped
  using PCI Base Address Registers.
  
  In case of I/O mapped ,I can use IN & OUT instructions 
  for accessing the configuration registers.

  In case of Memory mapped how do access the Configuration Registers.

  With regards,
     Anil