On Thu, Sep 16, 2010 at 5:06 PM, Wolfgang Denk <w...@denx.de> wrote: > Dear Alessandro Rubini, > > I agree that it would be nice to have U-Boot completely position- > independent and completelky restartable, but this would be a new > feature, which newer existed before. >
x86 has a nice feature whereby I can build two images that differ only by TEXT_BASE. I can build using TEXT_BASE somewhere in low memory, tftp the image and the 'go' directly to the base address of the image e.g. > tftp 6000000 u-boot.bin > go 6000000 This works because the x86 reset vector is at top of memory (0xfffffff0), not bottom (0x00000000) so the very first bytes of u-boot.bin are not the reset vector, but rather where the reset vector jumps to after performing some very low-level hardware init Both images, as a very first step, relocate to the highest available memory location and adjust all the relocation offsets in the image and jump into the relocated image. As long as I do not mess with the low-level init code, I can be confident that an image that 'boots' using the 'go' command will boot from Flash No, it is not a 'fully relocatable' image, but it is so close as to not make any real difference to me. Regards, Graeme _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
