Geert Uytterhoeven <ge...@linux-m68k.org> wrote: > On Mon, Sep 24, 2012 at 3:56 PM, George Spelvin <li...@horizon.com> wrote: >> SPARCv8 UMUL puts the high half of the 64-bit result into the Y >> register, and SPARCv7 has a multiply-step instruction (MULScc) which >> does likewise. > > Early SPARCs don't even have a multiply instruction.
Are you sure we're not talking about the same thing? Early SPARCs didn't have a *single* multiply instruction, but *did* have a multiply step instruction, which can be iterated to produce a 32x32->64-bit multiply. That's what I was referring to. All multiplies were slow, but widening multiply was no slower. And SPARCv7 had no divide support at all, so that was *really* slow. SPARClite added a divide step, but also added an integer multiply instruction, so again widening multiply beat the pants off divide. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/