Re: [U-Boot-Users] why jump at absolute address in start.S

In message 3E1507CA.7000305@sjtu.edu.cn you wrote:

I'm reading cpu/mpc8xx/start.S and found the following:

    /*
      * Calculate absolute address in FLASH and jump there
      */

     lis     r3, CFG_MONITOR_BASE@h
     ori     r3, r3, CFG_MONITOR_BASE@l
     addi    r3, r3, in_flash - _start + EXC_OFF_SYS_RESET
     mtlr    r3
     blr

Why do we need to calculate the absolutely address?

We want to jump to the address where our ciode resides in flash memory, so we must calculate the jump target.

Why should we do it here, instead of everywhere?

Please read the chapter of the 8xx User's Manual about how the processor starts from a reset.

Best regards, and a Happy New Year!

Wolfgang Denk