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> From: bgat@billgatliff.com > Cc: ColdFire@WildRice.com, crossgcc@sourceware.cygnus.com > > Keith, Rafael: > > > It's true that gcc/ld can be used to put code into ROM, but the whole > > process would be easier if gcc could generate Position Independant > > Code for the Motorola 68000/Coldfire family (the -fPIC option). > > PIC just to make the code movable, e.g. so it can run either in > > ROM or RAM? > Having truly PIC code solves a lot of problems, but I'm at a loss to > see how it would help any process that involves getting code into ROM. > If you're running code from ROM, why do you need to relocate it? Well it would be nice to be able to make a version of my bootloader that would run in ROM but could be copied to RAM at run time. Currently I have to make multiple version depending upon where they are to reside. > (I'm coming into this discussion from crossgcc, so I don't know what > the "this situation" refers to). Nor I---that seems to be the first occurrence of that phrase. In general there is no very specific situation, just a desire for PIC. > After a fashion, gcc can do PIC for most processors. Unfortunately, the Motorola 68000 family is not among them. > I suspect that the GOT approach was a poor-man's dynamic linker in an > OS-based environment, and not intended for embedded execute-from-ROM > setting. But still, depending on the "this situation" you're > referring to, it may be what you are looking for. > > Although, I *am* curious as to why gcc doesn't kick out PIC code using > PIC-type relative instructions... Mostly it does, if you mean using PC-relative branches. That's why I asked, it seems so close. The 68000 is to a great extent naturally position independant. If you say -fPIC you get syntax errors in the generated assembler, but it is clear that somebody was trying to make it work. ------ Want more information? See the CrossGCC FAQ, http://www.objsw.com/CrossGCC/ Want to unsubscribe? Send a note to crossgcc-unsubscribe@sourceware.cygnus.com
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