From: Denys Vlasenko <vda.linux@xxxxxxxxxxxxxx> Date: Wed, 25 Jun 2008 22:37:58 +0200 > On Wednesday 25 June 2008 18:01, Mikulas Patocka wrote: > > > Ingo's suggestion to talk to gcc people to remedy > > > insane call convention sounds as a more workable solution. > > > > > > BTW, i386 uses regparm call convention, is similar trick > > > possible for sparc64? > > > > Sparc64 has register windows: it passes arguments in registers, but it > > must allocate space for that registers. If the call stack is too deep (8 > > levels), the CPU runs out of registers and starts spilling the registers > > of the function 8-levels-deep to the stack. > > > > The stack usage could be reduced to 176 bytes with little work from gcc > > developers and to 128 bytes with more work (ABI change). If you wanted to > > Wow, it's nearly x2 reduction. > > ABI change in not a problem for kernel, since it is a "freestanding > application". Exactly like i386 switched to regparm, which is a different ABI. Except that nobody has written this code and therefore being about to use this unimplemented compiler facility to get correctness is not tenable. -- To unsubscribe from this list: send the line "unsubscribe sparclinux" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
