<div dir="ltr">On 18 August 2013 10:30, Mark Mueller <span dir="ltr"><<a href="mailto:markkmueller@gmail.com" target="_blank">markkmueller@gmail.com</a>></span> wrote:<br><div class="gmail_extra"><div class="gmail_quote"> <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">When the time comes, are there any concerns with using a 64 bit type, like portability? 64 bits for flags would be useful for something that I'm looking into and I'm curious how much pain that could cause.</div> </blockquote><div><br></div><div>We already use 64-bit bitfields in several places in Mesa--search src/mesa/main/mtypes.h for GLbitfield64 for some examples.</div><div><br></div><div>We also have the macros BITFIELD64_BIT(), BITFIELD64_MASK(), and BITFIELD64_RANGE() to make sure that the appropriate types are used for intermediate computations. For example:</div> <div><br></div><div>my_bitfield |= 1 << 33;</div><div><br></div><div>Is unsafe because 1 and 33 are 32-bit immediate values, so 1 << 33 is computed using 32-bit math. Whereas:</div><div><br></div><div>my_bitfield |= BITFIELD64_BIT(33);</div> <div><br></div><div>does the right thing.</div><div><br></div><div>As far as portability goes, it's not really a big issue in the i965 back-end since i965 graphics only exists on die with x86 :)</div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> <div class="gmail_extra"><br><br><div class="gmail_quote"><div><div class="h5">On Sun, Aug 18, 2013 at 10:58 AM, Ian Romanick <span dir="ltr"><<a href="mailto:idr@freedesktop.org" target="_blank">idr@freedesktop.org</a>></span> wrote:<br> </div></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><div class="h5"><div>On 08/18/2013 09:34 AM, Paul Berry wrote:<br> <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> We are getting close to the maximum number of BRW_NEW_* bits that can<br> be stored in brw->state.dirty.brw without overflowing 32 bits, and<br> geometry shaders are going to add more. Add a STATIC_ASSERT so that<br> we will be alerted when we need to switch to 64 bits.<br> </blockquote> <br></div> Good call.<br> <br> Reviewed-by: Ian Romanick <<a href="mailto:ian.d.romanick@intel.com" target="_blank">ian.d.romanick@intel.com</a>><div><div><br> <br> <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> ---<br> src/mesa/drivers/dri/i965/brw_<u></u>context.c | 5 +++++<br> src/mesa/drivers/dri/i965/brw_<u></u>context.h | 1 +<br> 2 files changed, 6 insertions(+)<br> <br> diff --git a/src/mesa/drivers/dri/i965/<u></u>brw_context.c b/src/mesa/drivers/dri/i965/<u></u>brw_context.c<br> index 11d438b..44a35d1 100644<br> --- a/src/mesa/drivers/dri/i965/<u></u>brw_context.c<br> +++ b/src/mesa/drivers/dri/i965/<u></u>brw_context.c<br> @@ -448,6 +448,11 @@ brwCreateContext(int api,<br> brw->state.dirty.mesa = ~0;<br> brw->state.dirty.brw = ~0;<br> <br> + /* Make sure that brw->state.dirty.brw has enough bits to hold all possible<br> + * dirty flags.<br> + */<br> + STATIC_ASSERT(BRW_NUM_STATE_<u></u>BITS <= 8 * sizeof(brw->state.dirty.brw));<br> +<br> brw->emit_state_always = 0;<br> <br> brw->batch.need_workaround_<u></u>flush = true;<br> diff --git a/src/mesa/drivers/dri/i965/<u></u>brw_context.h b/src/mesa/drivers/dri/i965/<u></u>brw_context.h<br> index 74e38f1..dbad507 100644<br> --- a/src/mesa/drivers/dri/i965/<u></u>brw_context.h<br> +++ b/src/mesa/drivers/dri/i965/<u></u>brw_context.h<br> @@ -155,6 +155,7 @@ enum brw_state_id {<br> BRW_STATE_UNIFORM_BUFFER,<br> BRW_STATE_META_IN_PROGRESS,<br> BRW_STATE_INTERPOLATION_MAP,<br> + BRW_NUM_STATE_BITS<br> };<br> <br> #define BRW_NEW_URB_FENCE (1 << BRW_STATE_URB_FENCE)<br> <br> </blockquote> <br></div></div></div></div><div><div> ______________________________<u></u>_________________<br> mesa-dev mailing list<br> <a href="mailto:mesa-dev@lists.freedesktop.org" target="_blank">mesa-dev@lists.freedesktop.org</a><br> <a href="http://lists.freedesktop.org/mailman/listinfo/mesa-dev" target="_blank">http://lists.freedesktop.org/<u></u>mailman/listinfo/mesa-dev</a><br> </div></div></blockquote></div><br></div> </blockquote></div><br></div></div>