[Mesa-dev] [PATCH 2/2] i915c: Use the actual MIN instruction.

[Ian Romanick]

On 02/10/2015 03:36 AM, Kenneth Graunke wrote:
> Matt Turner noticed that the hardware has always had a MIN
> instruction, but the driver always used MAX+MOV for no
> apparent reason.

And it has been right there in the docs the whole time too.  WTF?

> This should cut an instruction, and a temporary, allowing
> more programs to run in hardware.
> 
> Signed-off-by: Kenneth Graunke <kenneth at whitecape.org>

Reviewed-by: Ian Romanick <ian.d.romanick at intel.com>

> ---
>  src/mesa/drivers/dri/i915/i915_fragprog.c | 16 +---------------
>  1 file changed, 1 insertion(+), 15 deletions(-)
> 
> diff --git a/src/mesa/drivers/dri/i915/i915_fragprog.c b/src/mesa/drivers/dri/i915/i915_fragprog.c
> index 96fdd3c..d42da5a 100644
> --- a/src/mesa/drivers/dri/i915/i915_fragprog.c
> +++ b/src/mesa/drivers/dri/i915/i915_fragprog.c
> @@ -671,21 +671,7 @@ upload_program(struct i915_fragment_program *p)
>           break;
>  
>        case OPCODE_MIN:
> -         src0 = src_vector(p, &inst->SrcReg[0], program);
> -         src1 = src_vector(p, &inst->SrcReg[1], program);
> -         tmp = i915_get_utemp(p);
> -         flags = get_result_flags(inst);
> -
> -         i915_emit_arith(p,
> -                         A0_MAX,
> -                         tmp, flags & A0_DEST_CHANNEL_ALL, 0,
> -                         negate(src0, 1, 1, 1, 1),
> -                         negate(src1, 1, 1, 1, 1), 0);
> -
> -         i915_emit_arith(p,
> -                         A0_MOV,
> -                         get_result_vector(p, inst),
> -                         flags, 0, negate(tmp, 1, 1, 1, 1), 0, 0);
> +         EMIT_2ARG_ARITH(A0_MIN);
>           break;
>  
>        case OPCODE_MOV:
>