Hi ppl, Am a newbie to u-boot as well as arm assembly. wanted to know about the startup code. Below is the vector table pasted from the code. What i dont understand is why only the reset vector is PC relative and all others have memory allocated to hold the addresses. I mean all other vectors also could be branch instructions.Any reason ?

.globl _start _start: b reset ldr pc, _undefined_instruction ldr pc, _software_interrupt ldr pc, _prefetch_abort ldr pc, _data_abort ldr pc, _not_used ldr pc, _irq ldr pc, _fiq

_undefined_instruction: .word undefined_instruction _software_interrupt: .word software_interrupt _prefetch_abort: .word prefetch_abort _data_abort: .word data_abort _not_used: .word not_used _irq: .word irq _fiq: .word fiq

.balignl 16,0xdeadbeef Thanks and Regards, Srinivas Bakki

Hi, I have thought of an explanation can anyone please rectify if am wrong.

the load to PC instruction allows utilizing the full 32-bit address space for placement of the exception handlers, whereas the relative branch instruction is limited to +/- 25 bits relative to the current PC.

is that right ?

Regards, Srinivas Bakki

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