search for: fsub64

...-effects, they look pretty much like real instructions. Thus I have the idea to represent them in the tblgen instruction descriptions like pseudo-instructions, where constraints define which concrete physical %dX registers are to use. This would enfore correct register allocation. For example: def FSUB64: I<0x11, (ops), "fsub64", [(set d0, (fsub d0, d1))]>, Imp<[d0,d1],[d0,d1]>; // Uses d0, d1 and defines d0,d1 This seems to work, at least on simple test files. But I would also need a way to convert such a FSUB64 pseudo-instruction into the assembler...

...ke real instructions. Thus I have the idea to > represent them in the tblgen instruction descriptions like > pseudo-instructions, where constraints define which concrete physical > %dX registers are to use. This would enfore correct register > allocation. > > For example: > def FSUB64: I<0x11, (ops), "fsub64", [(set d0, (fsub d0, d1))]>, > Imp<[d0,d1],[d0,d1]>; // Uses d0, d1 and defines d0,d1 > > This seems to work, at least on simple test files. That should be a robust solution. > But I would also need a way to convert such a FSUB6...

Hi Chris, Thanks for this info. This provides even better and more advanced examples of multiclass usage! But your previous explanations were so good that I implemented in my backend last week almost the same that you've done now in the X86InstrSSE.td. I even introduced isCommutable parameter to indicate this property, just as you did. So, by now integer arithmetic and general purpose

For anyone interested, X86InstrSSE.td makes extensive use of multiclasses now if people are looking for examples other than the sparc backend. -Chris -- http://nondot.org/sabre/ http://llvm.org/

...ea to > > represent them in the tblgen instruction descriptions like > > pseudo-instructions, where constraints define which concrete > physical > > %dX registers are to use. This would enfore correct register > > allocation. > > > > For example: > > def FSUB64: I<0x11, (ops), "fsub64", [(set d0, (fsub d0, d1))]>, > > Imp<[d0,d1],[d0,d1]>; // Uses d0, d1 and defines d0,d1 > > > > This seems to work, at least on simple test files. > > That should be a robust solution. > > > But I would also...

On Tue, 10 Oct 2006, Roman Levenstein wrote: >>> such a call instruction? >> >> Why not just make the asm string be "call __fsub64"? > > Well, of course it would be the best solution. But the interesting part > is that I need to generate the machine code directly because for > different reasons use of a system assembler is not an option. As a ok. > result, I need to do this conversion in the target backen...

> On Tue, 10 Oct 2006, Roman Levenstein wrote: > >>> such a call instruction? > >> > >> Why not just make the asm string be "call __fsub64"? > > > > Well, of course it would be the best solution. But the interesting > part > > is that I need to generate the machine code directly because for > > different reasons use of a system assembler is not an option. As a > > ok. > > > result, I ne...