On Sunday, August 03, 2014 12:36:31 PM Chris Forbes wrote:
> We're about to be using this infrastructure to build descriptors in
> src1 of non-send instructions, when preparing to do an indirect send.
>
> Don't accidentally clobber the conditionalmod field of those
> instructions with SFID bits, which aren't part of the descriptor.
>
> Signed-off-by: Chris Forbes <chr...@ijw.co.nz>
> ---
> src/mesa/drivers/dri/i965/brw_eu_emit.c | 14 +++++++++++++-
> 1 file changed, 13 insertions(+), 1 deletion(-)
>
> diff --git a/src/mesa/drivers/dri/i965/brw_eu_emit.c
> b/src/mesa/drivers/dri/i965/brw_eu_emit.c
> index bc74de3..cdfc78e 100644
> --- a/src/mesa/drivers/dri/i965/brw_eu_emit.c
> +++ b/src/mesa/drivers/dri/i965/brw_eu_emit.c
> @@ -540,7 +540,19 @@ brw_set_message_descriptor(struct brw_compile *p,
> struct brw_context *brw = p->brw;
>
> brw_set_src1(p, inst, brw_imm_d(0));
> - brw_inst_set_sfid(brw, inst, sfid);
> +
> + /* For indirect sends, `inst` will not be the SEND/SENDC instruction
> + * itself; instead, it will be a MOV/OR into the address register.
> + *
> + * In this case, we avoid setting the extended message descriptor bits,
> + * since they go on the later SEND/SENDC instead and if set here would
> + * instead clobber the conditionalmod bits.
> + */
> + unsigned opcode = brw_inst_opcode(brw, inst);
> + if (opcode == BRW_OPCODE_SEND || opcode == BRW_OPCODE_SENDC) {
> + brw_inst_set_sfid(brw, inst, sfid);
> + }
> +
> brw_inst_set_mlen(brw, inst, msg_length);
> brw_inst_set_rlen(brw, inst, response_length);
> brw_inst_set_eot(brw, inst, end_of_thread);
> Hey Chris, I was originally confused by this - setting message descriptor bits on non-SEND instructions seemed bizarre to me. But, now that I've looked a bit more closely, I see what you're doing...the message descriptor bits are already in src1, so it actually is a convenient way to set up the right constant to copy into a0.0. Clever - nice work :) This series is: Reviewed-by: Kenneth Graunke <kenn...@whitecape.org>
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