Thanks. I'm working to port gcc to our chip. I use mips-elf as the start. Yet, we don't have pc-region branch instructions such as 'j target'. So I'm confused how to solve the function call translation. Thanks again.
Eric. 2006/2/14, Mike Stump <[EMAIL PROTECTED]>: > On Feb 13, 2006, at 7:28 PM, Eric Fisher wrote: > > Suppose I have only pc-relative branch instructions such as 'b offset' > > > > and don't have pc-region branch instructions such as 'j target'. So > > what the function call should be translated? Do I have to always use > > two instructions such as 'la reg, func' and 'b reg'? Especially when > > call a shared pic object file. > > > > The problem I've got is that when I link with a shared pic object > > file, there is a 'relocation truncated to fit' error. > > If you're a user, gcc-help is the appropriate list. If not, then > usually naming the chip, the options used, the rtl generated and > assembly used and so on would make the question easier to answer and > make the answer more accurate. > > The general answer is that -fPIC and -mlong-call should generate code > that uses the full width of a pointer without overflowing any fields, > getting relocation errors and so on. A port maintainer then can > choose _when_ to flip from medium code to large code, and that will > then drive what size objects one can link without -mlong-call. How > many bits can you go in medium mode on your port? How far did the > linker want to go? If less then the first, then, it's an as or > linker bug, if farther and you're not compiling with -mlong-call, > then, you'll need to. If you are, then you have a bug in -mlong-call > mode, you have to generate instructions that operate on the full > width of a pointer. > >
