Lpc2000

Hello Friends, 

I am using IAR EMBEDDED WORKBENCH.
The code shown below is produced by the IAR compiler.
I want to know what is the offset & how they are using the OFFSET in 
PC.

Can any one explain me the below program.


 MEMMAP = 2;
      LDR          R0, [PC,#0x354] [0x68C] =MEMMAP (0xE01FC040)
      MOV          R1, #2
      STRB         R1, [R0, #0]

  PINSEL0  = 0x0000000A;
 0x0000033C 48D4      LDR          R0, [PC,#0x350]; [0x690] =PINSEL0 
(0xE002C000)
 0x0000033E 210A      MOV          R1, #10
 0x00000340 6001      STR          R1, [R0, #0]


Explain me the LDR & how it points to this address.0xE01FC040

      LDR          R0, [PC,#0x354] [0x68C] =MEMMAP (0xE01FC040)

kindly help me,

with regards,
Rajendra R