ARM Initialization Question
gds at chartertn.net
Fri Sep 12 19:16:26 UTC 2008
Sebastian Huber wrote:
> I am quite new to the ARM architecture and try to develop a BSP for the
> LPC2478. I have a question to the initialization code (random start.S):
> /* Set up the SVC stack pointer last and stay in SVC mode */
> mov r0, #(PSR_MODE_SVC | PSR_I | PSR_F) /* No interrupts */
> msr cpsr, r0
> ldr r1, =_svc_stack_size
> ldr sp, =_svc_stack
> add sp, sp, r1
> sub sp, sp, #0x64
> Why is 0x64 subtracted from the stack pointer?
I ran my app and skipped the subtract of 100 and it still worked OK.
Seems like it is just wasting 100 bytes!
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