El 30/04/18 a las 23:14, Jason Ekstrand escribió:
>
>
> On Mon, Apr 30, 2018 at 7:18 AM, Iago Toral Quiroga <ito...@igalia.com
> <mailto:ito...@igalia.com>> wrote:
>
> From: Jose Maria Casanova Crespo <jmcasan...@igalia.com
> <mailto:jmcasan...@igalia.com>>
>
> From Intel Skylake PRM, vol 07, "Immediate" section (page 768):
>
> "For a word, unsigned word, or half-float immediate data,
> software must replicate the same 16-bit immediate value to both
> the lower word and the high word of the 32-bit immediate field
> in a GEN instruction."
>
> This patch implements float16 negate and fix the int16/uint16
> negate that wasn't taking into account the replication in lower
> and higher words.
>
>
> Since this fixes a bug, do we want to split it in two and send the
> bug-fix to stable?
Makes sense to split. I'm going to send for stable also the brw_imm_w patch.
I detected the same issue with brw_abs_immediate. So I'm including it in
the v3 of this patch.
>
> v2: Integer cases are different to Float cases. (Jason Ekstrand)
> Included reference to PRM (Jose Maria Casanova)
> ---
> src/intel/compiler/brw_shader.cpp | 11 +++++++----
> 1 file changed, 7 insertions(+), 4 deletions(-)
>
> diff --git a/src/intel/compiler/brw_shader.cpp
> b/src/intel/compiler/brw_shader.cpp
> index 9cdf9fcb23..76dd1173fa 100644
> --- a/src/intel/compiler/brw_shader.cpp
> +++ b/src/intel/compiler/brw_shader.cpp
> @@ -580,8 +580,13 @@ brw_negate_immediate(enum brw_reg_type type,
> struct brw_reg *reg)
> reg->d = -reg->d;
> return true;
> case BRW_REGISTER_TYPE_W:
> - case BRW_REGISTER_TYPE_UW:
> - reg->d = -(int16_t)reg->ud;
> + case BRW_REGISTER_TYPE_UW: {
> + uint16_t value = -(int16_t)reg->ud;
> + reg->ud = value | value << 16;
>
>
> You're shifting an explicitly 16-bit value by 16. I think you want to
> cast to uint32_t.
As agreed I'll change this for:
reg->ud = value | (uint32_t) value << 16;
> + return true;
> + }
> + case BRW_REGISTER_TYPE_HF:
> + reg->ud ^= 0x80008000;
> return true;
> case BRW_REGISTER_TYPE_F:
> reg->f = -reg->f;
> @@ -602,8 +607,6 @@ brw_negate_immediate(enum brw_reg_type type,
> struct brw_reg *reg)
> case BRW_REGISTER_TYPE_UV:
> case BRW_REGISTER_TYPE_V:
> assert(!"unimplemented: negate UV/V immediate");
> - case BRW_REGISTER_TYPE_HF:
> - assert(!"unimplemented: negate HF immediate");
> case BRW_REGISTER_TYPE_NF:
> unreachable("no NF immediates");
> }
> --
> 2.14.1
>
>
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