On Tue, Jun 28, 2016 at 10:45 AM, Samuel Pitoiset <samuel.pitoi...@gmail.com> wrote: > > > On 06/28/2016 04:38 PM, Ilia Mirkin wrote: >> >> On Tue, Jun 28, 2016 at 10:27 AM, Samuel Pitoiset >> <samuel.pitoi...@gmail.com> wrote: >>> >>> >>> >>> On 06/28/2016 04:23 PM, Ilia Mirkin wrote: >>>> >>>> >>>> On Tue, Jun 28, 2016 at 10:21 AM, Samuel Pitoiset >>>> <samuel.pitoi...@gmail.com> wrote: >>>>> >>>>> >>>>> On 06/28/2016 04:15 PM, Ilia Mirkin wrote: >>>>>> >>>>>> >>>>>> >>>>>> Again, what problem was this patch trying to solve? >>>>> >>>>> >>>>> >>>>> >>>>> The problem is that FADD can only emits 19-bits but longIMMD() will >>>>> return >>>>> false because it only checks for the high 12-bits. >>>>> >>>>> I don't know if you saw my messages on IRC but I found some other >>>>> issues >>>>> with longIMMD() and emitIMMD(). >>>> >>>> >>>> >>>> Nope, it will emit 19 bits and then the 20th (high aka sign) bit as >>>> well, just to a different location. [And the bottom 12 bits are >>>> guaranteed to be 0.] >>>> >>>> What's a specific example that you think it doesn't emit correctly? >>> >>> >>> >>> I don't have any shaders which hit that issue, but I think it's similar >>> to >>> the fix I did for IMUL32I. The immediate value was 0xf4240 in that >>> specific >>> case, and IMUL emitted 0x74240 instead... because the sign bit was used >>> to >>> emit the NEG modifier. >> >> >> Right, which isn't the same thing for ints, but is the same thing for >> floats. For integer immediates, it's also the low 20 bits, not the >> high 20 bits. And I believe that the condition should be ensuring that >> all 12 of the high bits are the same. But perhaps it doesn't properly >> check that those 12 bits have the same value as the 20th bit? > > > Yes, it does not do that.
Well, you need to figure out what the correct thing is for integers. If it's a sign bit, then we have to flip the sign on the immediate before emission too (since it's all 2's complement, not s-mag). Or if it's all the high bits. And either way, adjust the target to cope with the new restrictions, if any. -ilia _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/mesa-dev
