On 7/19/05, Ralf Baechle <ralf@xxxxxxxxxxxxxx> wrote: > On Tue, Jul 19, 2005 at 10:00:20PM +0530, Kishore K wrote: > > > We are facing a problem when U-boot is compiled with gcc 3.x > > > > U-boot uses the following instruction in one of the files. > > > > bal jump_to_symbol > > > > This code gets compiled without any problem with gcc2. However, if I > > compile the code > > with gcc3, it exits with the error "Cannot branch to unknown symbol". > > > > What should we do to circumvent this problem ? > > > > I replaced > > > > bal jump_to_symbol > > > > by > > > > la t9, jump_to_symbol > > jalr t9 > > > > Then code gets compiled properly without any problem. Please let me > > know, whether this > > is correct way of fixing the problem. I am newbie to MIPS assembly > > language. Why this > > change is required with gcc 3.x compiler ? > > FIrst of all, gcc doesn't care at all about your assembler code, that's > the assembler which you must have changed along with that. > > There used to be no relocation type to represent a branch to an external > symbol in an ELF file which is why gas is throwing an error message, so > gas is throwing an error message. Latest gas fixed that shortcoming. > I think there was a bug in somewhat older gas which resulted in such > invalid code actually being accepted even though it shouldn't have been. > > Ralf Thank you very much for the reply. First of all code got compiled only after removing the option -mips-allow-branch-to-undefined from Makefile. If this option is included, compilation fails saying that option is invalid. I am using binutils-2.14.90.06. Same problem is observed even with binutils 2.15.94.0.2.2. Do you mean to say that no change is required in the code snippet bal jump_to_symbol and code should get compiled with the latest assembler without any problem. Please clearify. TIA, --kishore
