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
0x00900000.
any help will be greatly appreaciated.
regards
Sujith