<div dir="ltr"><div>FWIW, I think UCMP is a misleading name. Whatever the name will be, it should be prefixed with "I" or "U", because it's not a floating-point opcode. How about UCND? :D </div> Marek </div><div class="gmail_extra"> <div class="gmail_quote">On Thu, Apr 4, 2013 at 6:23 PM, Jose Fonseca <<a href="mailto:jfonseca@vmware.com" target="_blank">jfonseca@vmware.com</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">There might be some value in renaming UCMP to be MOVC though. I think everybody here can agree that UCMP, though semantically correct, is misleading. Jose <div class="HOEnZb"><div class="h5"> ----- Original Message ----- > Hah, yea, I'm sorry, that's a good point. So movc is a bitcast to unsigned > followed by ucmp. Alright, I'm withdrawing the patch. > > z > > ----- Original Message ----- > > > > > > ----- Original Message ----- > > > > > Erm, unsigned < 0 doesn't make sense. > > > > > > > > Ah indeed! > > > > > > > > > Definitely what the description says: > > > > > static void > > > > > micro_ucmp(union tgsi_exec_channel *dst, > > > > > const union tgsi_exec_channel *src0, > > > > > const union tgsi_exec_channel *src1, > > > > > const union tgsi_exec_channel *src2) > > > > > { > > > > > dst->u[0] = src0->u[0] ? src1->u[0] : src2->u[0]; > > > > > dst->u[1] = src0->u[1] ? src1->u[1] : src2->u[1]; > > > > > dst->u[2] = src0->u[2] ? src1->u[2] : src2->u[2]; > > > > > dst->u[3] = src0->u[3] ? src1->u[3] : src2->u[3]; > > > > > } > > > > > > > > > > or > > > > > > > > > > case TGSI_OPCODE_UCMP: > > > > > case TGSI_OPCODE_CMP: > > > > > FOR_EACH_DST_ENABLED_CHANNEL(0, c, tgsi) { > > > > > src0 = fetchSrc(0, c); > > > > > src1 = fetchSrc(1, c); > > > > > src2 = fetchSrc(2, c); > > > > > if (src1 == src2) > > > > > mkMov(dst0[c], src1); > > > > > else > > > > > mkCmp(OP_SLCT, (srcTy == TYPE_F32) ? CC_LT(less than 0) : > > > > > CC_NE(not equal 0), > > > > > srcTy, dst0[c], src1, src2, src0); > > > > > } > > > > > > > > > > > > > But odd enough, the implementations I happend to look at seemed to do > > > > "foo > > > > >= > > > > 0": > > > > > > Yea, like I mentioned it's pretty broken. Sometimes it's implemented as > > > UCMP, > > > sometimes it's implemented as MOVC. > > > It seems to be used only as MOVC. > > > It feels silly writing this, but we should probably make UCMP act like > > > UCMP > > > and add MOVC and use it when we need a MOVC. > > > > Zack, I believe Christoph has a point when he says that UCMP is > > semantically > > the same as MOVC. > > > > Because for unsigned integers, "foo > 0" is the same as "foo != 0", > > therefore > > having UCMP defined as > > > > dst = src0 > 0 ? src1 : src2 > > > > or a MOVC as > > > > dst = src0 != 0 ? src1 : src2 > > > > is pretty much the same. > > > > Jose > > > > > _______________________________________________ mesa-dev mailing list <a href="mailto:mesa-dev@lists.freedesktop.org">mesa-dev@lists.freedesktop.org</a> <a href="http://lists.freedesktop.org/mailman/listinfo/mesa-dev" target="_blank">http://lists.freedesktop.org/mailman/listinfo/mesa-dev</a> </div></div></blockquote></div> </div>