[Mesa-dev] [PATCH] r300/compiler: Implement ROUND

[Corbin Simpson]

Sending from a mobile, pardon my terseness. ~ C.
On Aug 23, 2011 2:42 PM, "Tom Stellard" <tstellar at gmail.com> wrote:
> According to the GLSL spec, the implementor can decide which way to round
> when the fraction is .5. The r300 compiler will round down, so we can use
> CND and save an instruction.
> ---
>
> MLAA should work on r300g (r500 only) with this patch. I've tested
> with the kasanen-post-process-v2 branch and it looks OK to me, but it
> would be nice to have a second opinion.
>
> I was testing with: pp_jimenezmlaa=8 glxgears
>
> src/gallium/drivers/r300/compiler/radeon_opcodes.c | 7 +++
> src/gallium/drivers/r300/compiler/radeon_opcodes.h | 3 +
> .../drivers/r300/compiler/radeon_program_alu.c | 54 ++++++++++++++++++++
> src/gallium/drivers/r300/r300_tgsi_to_rc.c | 2 +-
> 4 files changed, 65 insertions(+), 1 deletions(-)
>
> diff --git a/src/gallium/drivers/r300/compiler/radeon_opcodes.c
b/src/gallium/drivers/r300/compiler/radeon_opcodes.c
> index afd78ad..527db9a 100644
> --- a/src/gallium/drivers/r300/compiler/radeon_opcodes.c
> +++ b/src/gallium/drivers/r300/compiler/radeon_opcodes.c
> @@ -246,6 +246,13 @@ struct rc_opcode_info rc_opcodes[MAX_RC_OPCODE] = {
> .IsStandardScalar = 1
> },
> {
> + .Opcode = RC_OPCODE_ROUND,
> + .Name = "ROUND",
> + .NumSrcRegs = 1,
> + .HasDstReg = 1,
> + .IsComponentwise = 1
> + },
> + {
> .Opcode = RC_OPCODE_RSQ,
> .Name = "RSQ",
> .NumSrcRegs = 1,
> diff --git a/src/gallium/drivers/r300/compiler/radeon_opcodes.h
b/src/gallium/drivers/r300/compiler/radeon_opcodes.h
> index b586882..968dc7b 100644
> --- a/src/gallium/drivers/r300/compiler/radeon_opcodes.h
> +++ b/src/gallium/drivers/r300/compiler/radeon_opcodes.h
> @@ -133,6 +133,9 @@ typedef enum {
> /** scalar instruction: dst = 1 / src0.x */
> RC_OPCODE_RCP,
>
> + /** vec4 instruction: dst.c = frc(src0.c) > 0.5 ? ceil(src0.c) :
floor(src0.c) */
> + RC_OPCODE_ROUND,
> +
> /** scalar instruction: dst = 1 / sqrt(src0.x) */
> RC_OPCODE_RSQ,
>
> diff --git a/src/gallium/drivers/r300/compiler/radeon_program_alu.c
b/src/gallium/drivers/r300/compiler/radeon_program_alu.c
> index e273bc4..0bfd2dc 100644
> --- a/src/gallium/drivers/r300/compiler/radeon_program_alu.c
> +++ b/src/gallium/drivers/r300/compiler/radeon_program_alu.c
> @@ -104,6 +104,13 @@ static const struct rc_src_register builtin_one = {
> .Index = 0,
> .Swizzle = RC_SWIZZLE_1111
> };
> +
> +static const struct rc_src_register builtin_half = {
> + .File = RC_FILE_NONE,
> + .Index = 0,
> + .Swizzle = RC_SWIZZLE_HHHH
> +};
> +
> static const struct rc_src_register srcreg_undefined = {
> .File = RC_FILE_NONE,
> .Index = 0,
> @@ -416,6 +423,52 @@ static void transform_POW(struct radeon_compiler* c,
> rc_remove_instruction(inst);
> }
>
> +/* dst = ROUND(src) :
> + * frac = FRC(src)
> + * low = src - frac
> + * high = low + 1
> + * dst = CND high, low, frac
> + *
> + * According to the GLSL spec, the implementor can decide which way to
round
> + * when the fraction is .5. In this case we round down, so we can use
> + * CND and save an instruction.
> + *
> + * The optimizer should reduce this sequence to 3 instructions using
> + * presubtract.
> + */
> +static void transform_ROUND(struct radeon_compiler* c,
> + struct rc_instruction* inst)
> +{
> + unsigned int mask = inst->U.I.DstReg.WriteMask;
> + unsigned int frac_index, low_index, high_index;
> + struct rc_dst_register frac_dst, low_dst, high_dst;
> + struct rc_src_register frac_src, low_src, high_src;
> +
> + /* frac = FRC(src) */
> + frac_index = rc_find_free_temporary(c);
> + frac_dst = dstregtmpmask(frac_index, mask);
> + emit1(c, inst->Prev, RC_OPCODE_FRC, 0, frac_dst, inst->U.I.SrcReg[0]);
> + frac_src = srcreg(RC_FILE_TEMPORARY, frac_dst.Index);
> +
> + /* low = src - frc */
> + low_index = rc_find_free_temporary(c);
> + low_dst = dstregtmpmask(low_index, mask);
> + emit2(c, inst->Prev, RC_OPCODE_ADD, 0, low_dst,
> + negate(inst->U.I.SrcReg[0]), frac_src);
> + low_src = srcreg(RC_FILE_TEMPORARY, low_dst.Index);
> +
> + /* high = low + 1 */
> + high_index = rc_find_free_temporary(c);
> + high_dst = dstregtmpmask(high_index, mask);
> + emit2(c, inst->Prev, RC_OPCODE_ADD, 0, high_dst, low_src, builtin_one);
> + high_src = srcreg(RC_FILE_TEMPORARY, high_dst.Index);
> +
> + /* dst = CND high, low, frac */
> + emit3(c, inst->Prev, RC_OPCODE_CND, 0, inst->U.I.DstReg,
> + high_src, low_src, frac_src);
> + rc_remove_instruction(inst);
> +}
> +
> static void transform_RSQ(struct radeon_compiler* c,
> struct rc_instruction* inst)
> {
> @@ -599,6 +652,7 @@ int radeonTransformALU(
> case RC_OPCODE_LIT: transform_LIT(c, inst); return 1;
> case RC_OPCODE_LRP: transform_LRP(c, inst); return 1;
> case RC_OPCODE_POW: transform_POW(c, inst); return 1;
> + case RC_OPCODE_ROUND: transform_ROUND(c, inst); return 1;
> case RC_OPCODE_RSQ: transform_RSQ(c, inst); return 1;
> case RC_OPCODE_SEQ: transform_SEQ(c, inst); return 1;
> case RC_OPCODE_SFL: transform_SFL(c, inst); return 1;
> diff --git a/src/gallium/drivers/r300/r300_tgsi_to_rc.c
b/src/gallium/drivers/r300/r300_tgsi_to_rc.c
> index 07a3f3c..4cb08b5 100644
> --- a/src/gallium/drivers/r300/r300_tgsi_to_rc.c
> +++ b/src/gallium/drivers/r300/r300_tgsi_to_rc.c
> @@ -57,7 +57,7 @@ static unsigned translate_opcode(unsigned opcode)
> case TGSI_OPCODE_FRC: return RC_OPCODE_FRC;
> case TGSI_OPCODE_CLAMP: return RC_OPCODE_CLAMP;
> case TGSI_OPCODE_FLR: return RC_OPCODE_FLR;
> - /* case TGSI_OPCODE_ROUND: return RC_OPCODE_ROUND; */
> + case TGSI_OPCODE_ROUND: return RC_OPCODE_ROUND;
> case TGSI_OPCODE_EX2: return RC_OPCODE_EX2;
> case TGSI_OPCODE_LG2: return RC_OPCODE_LG2;
> case TGSI_OPCODE_POW: return RC_OPCODE_POW;
> --
> 1.7.3.4
>
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> mesa-dev at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/mesa-dev
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