stack pb with IPL

Hello, I does not understand the examples of 800fads.lnk’s file for the IPL.
In the directory 800fads, the stack is define with SP_INIT = 0x2000 and
SP_END = 0x2800. The boot code init8xx initializes the stack pointeur to
SP_INIT, and when we reserve the stack, the pointeur (R1) is decrease and
thus it is to lower than 0x2000. Why we do not initialize the pointeur to
SP_END so that it decrease in the common sense. Have we to invert SP_INIT
and SP_END ?