Ravishankar S <ravishankar.s@xxxxxxxxxxx> writes: > But TriCore's EABI specifies separate registers for passing arguments > and returning values. D2-D3 for returning values and D4-D7 for passing > arguments. > > My question is : Will it make a difference from a compiler writer's > point for this type of calling convention. From experience, will it make > for a differnce in performance. It won't make much difference. There are other architectures with similar characteristics. For example, on MIPS arguments are passed in $4 through $7 or $11 (depending on the ABI), but values are returned in $2 and $3. > On the surface, it seems like it does, as there most of functions do not > return values and most anyway don't return 64 bit values. So reusing the > registers as PowerPC does may be better. The return registers are essentially just caller-saved scratch registers. I suppose if you are short on registers you might prefer to have more callee-saved registers. But if you have enough registers, it doesn't matter much either way. Ian
