serial bootloader

hi all, i am a newbie to both Embedded field and ARM. there is some constants in the following file, include/asm-arm/arch-integrator/platform.h, like, #define INTEGRATOR_SDRAM_BASE 0x00040000 #define INTEGRATOR_SDRAM_ALIAS_BASE 0x80000000 #define INTEGRATOR_HDR0_SDRAM_BASE 0x80000000 #define INTEGRATOR_HDR1_SDRAM_BASE 0x90000000 #define INTEGRATOR_HDR2_SDRAM_BASE 0xA0000000 #define INTEGRATOR_HDR3_SDRAM_BASE 0xB0000000 but here my actual SDRAM BASE starts at 0x00900000. also, the address 0x80000000 is for the memory map for my USB. so how do i configure these constants if my INTEGRATOR_SDRAM_BASE is