Uboot中的TEXT_BASE值是如何取定的

开发板的UBoot源代码中取的TEXT_BASE = 0x33D80000，请问这个值是怎么取定的呢？

同问 移植u-boot-1.1.6到TQ2440文档中为什么要修改 TEXT_BASE

修改board/dong2440/config.mk文件如下：
TEXT_BASE = 0x33000000
#TEXT_BASE = 0x33F80000
不修改的话 即使用原始值 TEXT_BASE = 0x33F80000
有没有什么影响?
PS:
#
# SMDK2410 has 1 bank of 64 MB DRAM
#
# 3000'0000 to 3400'0000
#
# Linux-Kernel is expected to be at 3000'8000, entry 3000'8000
# optionally with a ramdisk at 3080'0000
#
# we load ourself to 33F8'0000
#
# download area is 3300'0000
#