[Mesa-dev] [PATCH v2 3/5] r600: implement DDIV
Nicolai Hähnle
nicolai.haehnle at amd.com
Thu Jan 19 17:40:27 UTC 2017
On 19.01.2017 17:50, Ilia Mirkin wrote:
> NVIDIA can't do division either (double or otherwise - but double is
> even worse since the rcp is only half there). It has some fancy
> functions which get things like division, sqrt, etc.
What does that mean, precisely? It might make sense to have a cap-bit
after all, and then if somebody can be bothered to do it, have the
front-end generate TGSI for the kind of Newton-Raphson code that LLVM
implements for GCN.
Nicolai
>
> 2017-01-19 11:39 GMT-05:00 Roland Scheidegger <sroland at vmware.com>:
>> Double-capable Evergreen/NI can't do ddiv? Interesting. I wonder how
>> it's made d3d11 double conformant...
>>
>> Roland
>>
>> Am 19.01.2017 um 14:59 schrieb Nicolai Hähnle:
>>> From: Nicolai Hähnle <nicolai.haehnle at amd.com>
>>>
>>> ---
>>> src/gallium/drivers/r600/r600_shader.c | 59 ++++++++++++++++++++++++++++++++++
>>> 1 file changed, 59 insertions(+)
>>>
>>> diff --git a/src/gallium/drivers/r600/r600_shader.c b/src/gallium/drivers/r600/r600_shader.c
>>> index 5c4bc91..eaabb04 100644
>>> --- a/src/gallium/drivers/r600/r600_shader.c
>>> +++ b/src/gallium/drivers/r600/r600_shader.c
>>> @@ -4384,20 +4384,77 @@ static int cayman_mul_double_instr(struct r600_shader_ctx *ctx)
>>> alu.last = 1;
>>> r = r600_bytecode_add_alu(ctx->bc, &alu);
>>> if (r)
>>> return r;
>>> }
>>>
>>> return 0;
>>> }
>>>
>>> /*
>>> + * Emit RECIP_64 + MUL_64 to implement division.
>>> + */
>>> +static int cayman_ddiv_instr(struct r600_shader_ctx *ctx)
>>> +{
>>> + struct tgsi_full_instruction *inst = &ctx->parse.FullToken.FullInstruction;
>>> + int r;
>>> + struct r600_bytecode_alu alu;
>>> + int t1 = ctx->temp_reg;
>>> + int k;
>>> +
>>> + /* Only support one double at a time. This is the same constraint as
>>> + * in DMUL lowering. */
>>> + assert(inst->Dst[0].Register.WriteMask == TGSI_WRITEMASK_XY ||
>>> + inst->Dst[0].Register.WriteMask == TGSI_WRITEMASK_ZW);
>>> +
>>> + k = inst->Dst[0].Register.WriteMask == TGSI_WRITEMASK_XY ? 0 : 1;
>>> +
>>> + r = cayman_emit_unary_double_raw(ctx->bc, ALU_OP2_RECIP_64, t1, &ctx->src[1], false);
>>> + if (r)
>>> + return r;
>>> +
>>> + for (int i = 0; i < 4; i++) {
>>> + memset(&alu, 0, sizeof(struct r600_bytecode_alu));
>>> + alu.op = ALU_OP2_MUL_64;
>>> +
>>> + r600_bytecode_src(&alu.src[0], &ctx->src[0], k * 2 + ((i == 3) ? 0 : 1));
>>> +
>>> + alu.src[1].sel = t1;
>>> + alu.src[1].chan = (i == 3) ? 0 : 1;
>>> +
>>> + alu.dst.sel = t1;
>>> + alu.dst.chan = i;
>>> + alu.dst.write = 1;
>>> + if (i == 3)
>>> + alu.last = 1;
>>> + r = r600_bytecode_add_alu(ctx->bc, &alu);
>>> + if (r)
>>> + return r;
>>> + }
>>> +
>>> + for (int i = 0; i < 2; i++) {
>>> + memset(&alu, 0, sizeof(struct r600_bytecode_alu));
>>> + alu.op = ALU_OP1_MOV;
>>> + alu.src[0].sel = t1;
>>> + alu.src[0].chan = i;
>>> + tgsi_dst(ctx, &inst->Dst[0], k * 2 + i, &alu.dst);
>>> + alu.dst.write = 1;
>>> + if (i == 1)
>>> + alu.last = 1;
>>> + r = r600_bytecode_add_alu(ctx->bc, &alu);
>>> + if (r)
>>> + return r;
>>> + }
>>> + return 0;
>>> +}
>>> +
>>> +/*
>>> * r600 - trunc to -PI..PI range
>>> * r700 - normalize by dividing by 2PI
>>> * see fdo bug 27901
>>> */
>>> static int tgsi_setup_trig(struct r600_shader_ctx *ctx)
>>> {
>>> int r;
>>> struct r600_bytecode_alu alu;
>>>
>>> memset(&alu, 0, sizeof(struct r600_bytecode_alu));
>>> @@ -9393,20 +9450,21 @@ static const struct r600_shader_tgsi_instruction eg_shader_tgsi_instruction[] =
>>> [TGSI_OPCODE_UMSB] = { ALU_OP1_FFBH_UINT, tgsi_msb},
>>> [TGSI_OPCODE_INTERP_CENTROID] = { ALU_OP0_NOP, tgsi_interp_egcm},
>>> [TGSI_OPCODE_INTERP_SAMPLE] = { ALU_OP0_NOP, tgsi_interp_egcm},
>>> [TGSI_OPCODE_INTERP_OFFSET] = { ALU_OP0_NOP, tgsi_interp_egcm},
>>> [TGSI_OPCODE_F2D] = { ALU_OP1_FLT32_TO_FLT64, tgsi_op2_64},
>>> [TGSI_OPCODE_D2F] = { ALU_OP1_FLT64_TO_FLT32, tgsi_op2_64_single_dest},
>>> [TGSI_OPCODE_DABS] = { ALU_OP1_MOV, tgsi_op2_64},
>>> [TGSI_OPCODE_DNEG] = { ALU_OP2_ADD_64, tgsi_dneg},
>>> [TGSI_OPCODE_DADD] = { ALU_OP2_ADD_64, tgsi_op2_64},
>>> [TGSI_OPCODE_DMUL] = { ALU_OP2_MUL_64, cayman_mul_double_instr},
>>> + [TGSI_OPCODE_DDIV] = { 0, cayman_ddiv_instr },
>>> [TGSI_OPCODE_DMAX] = { ALU_OP2_MAX_64, tgsi_op2_64},
>>> [TGSI_OPCODE_DMIN] = { ALU_OP2_MIN_64, tgsi_op2_64},
>>> [TGSI_OPCODE_DSLT] = { ALU_OP2_SETGT_64, tgsi_op2_64_single_dest_s},
>>> [TGSI_OPCODE_DSGE] = { ALU_OP2_SETGE_64, tgsi_op2_64_single_dest},
>>> [TGSI_OPCODE_DSEQ] = { ALU_OP2_SETE_64, tgsi_op2_64_single_dest},
>>> [TGSI_OPCODE_DSNE] = { ALU_OP2_SETNE_64, tgsi_op2_64_single_dest},
>>> [TGSI_OPCODE_DRCP] = { ALU_OP2_RECIP_64, cayman_emit_double_instr},
>>> [TGSI_OPCODE_DSQRT] = { ALU_OP2_SQRT_64, cayman_emit_double_instr},
>>> [TGSI_OPCODE_DMAD] = { ALU_OP3_FMA_64, tgsi_op3_64},
>>> [TGSI_OPCODE_DFMA] = { ALU_OP3_FMA_64, tgsi_op3_64},
>>> @@ -9615,20 +9673,21 @@ static const struct r600_shader_tgsi_instruction cm_shader_tgsi_instruction[] =
>>> [TGSI_OPCODE_UMSB] = { ALU_OP1_FFBH_UINT, tgsi_msb},
>>> [TGSI_OPCODE_INTERP_CENTROID] = { ALU_OP0_NOP, tgsi_interp_egcm},
>>> [TGSI_OPCODE_INTERP_SAMPLE] = { ALU_OP0_NOP, tgsi_interp_egcm},
>>> [TGSI_OPCODE_INTERP_OFFSET] = { ALU_OP0_NOP, tgsi_interp_egcm},
>>> [TGSI_OPCODE_F2D] = { ALU_OP1_FLT32_TO_FLT64, tgsi_op2_64},
>>> [TGSI_OPCODE_D2F] = { ALU_OP1_FLT64_TO_FLT32, tgsi_op2_64_single_dest},
>>> [TGSI_OPCODE_DABS] = { ALU_OP1_MOV, tgsi_op2_64},
>>> [TGSI_OPCODE_DNEG] = { ALU_OP2_ADD_64, tgsi_dneg},
>>> [TGSI_OPCODE_DADD] = { ALU_OP2_ADD_64, tgsi_op2_64},
>>> [TGSI_OPCODE_DMUL] = { ALU_OP2_MUL_64, cayman_mul_double_instr},
>>> + [TGSI_OPCODE_DDIV] = { 0, cayman_ddiv_instr },
>>> [TGSI_OPCODE_DMAX] = { ALU_OP2_MAX_64, tgsi_op2_64},
>>> [TGSI_OPCODE_DMIN] = { ALU_OP2_MIN_64, tgsi_op2_64},
>>> [TGSI_OPCODE_DSLT] = { ALU_OP2_SETGT_64, tgsi_op2_64_single_dest_s},
>>> [TGSI_OPCODE_DSGE] = { ALU_OP2_SETGE_64, tgsi_op2_64_single_dest},
>>> [TGSI_OPCODE_DSEQ] = { ALU_OP2_SETE_64, tgsi_op2_64_single_dest},
>>> [TGSI_OPCODE_DSNE] = { ALU_OP2_SETNE_64, tgsi_op2_64_single_dest},
>>> [TGSI_OPCODE_DRCP] = { ALU_OP2_RECIP_64, cayman_emit_double_instr},
>>> [TGSI_OPCODE_DSQRT] = { ALU_OP2_SQRT_64, cayman_emit_double_instr},
>>> [TGSI_OPCODE_DMAD] = { ALU_OP3_FMA_64, tgsi_op3_64},
>>> [TGSI_OPCODE_DFMA] = { ALU_OP3_FMA_64, tgsi_op3_64},
>>>
>>
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