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25 #ifndef BRW_FS_BUILDER_H
26 #define BRW_FS_BUILDER_H
28 #include "brw_ir_fs.h"
29 #include "brw_shader.h"
30 #include "brw_context.h"
34 * Toolbox to assemble an FS IR program out of individual instructions.
36 * This object is meant to have an interface consistent with
37 * brw::vec4_builder. They cannot be fully interchangeable because
38 * brw::fs_builder generates scalar code while brw::vec4_builder generates
43 /** Type used in this IR to represent a source of an instruction. */
44 typedef fs_reg src_reg
;
46 /** Type used in this IR to represent the destination of an instruction. */
47 typedef fs_reg dst_reg
;
49 /** Type used in this IR to represent an instruction. */
50 typedef fs_inst instruction
;
53 * Construct an fs_builder that inserts instructions into \p shader.
54 * \p dispatch_width gives the native execution width of the program.
56 fs_builder(backend_shader
*shader
,
57 unsigned dispatch_width
) :
58 shader(shader
), block(NULL
), cursor(NULL
),
59 _dispatch_width(dispatch_width
),
61 force_writemask_all(false),
67 * Construct an fs_builder that inserts instructions into \p shader
68 * before instruction \p inst in basic block \p block. The default
69 * execution controls and debug annotation are initialized from the
70 * instruction passed as argument.
72 fs_builder(backend_shader
*shader
, bblock_t
*block
, fs_inst
*inst
) :
73 shader(shader
), block(block
), cursor(inst
),
74 _dispatch_width(inst
->exec_size
),
75 _group(inst
->force_sechalf
? 8 : 0),
76 force_writemask_all(inst
->force_writemask_all
)
78 annotation
.str
= inst
->annotation
;
79 annotation
.ir
= inst
->ir
;
83 * Construct an fs_builder that inserts instructions before \p cursor in
84 * basic block \p block, inheriting other code generation parameters
88 at(bblock_t
*block
, exec_node
*cursor
) const
90 fs_builder bld
= *this;
97 * Construct an fs_builder appending instructions at the end of the
98 * instruction list of the shader, inheriting other code generation
99 * parameters from this.
104 return at(NULL
, (exec_node
*)&shader
->instructions
.tail
);
108 * Construct a builder specifying the default SIMD width and group of
109 * channel enable signals, inheriting other code generation parameters
112 * \p n gives the default SIMD width, \p i gives the slot group used for
113 * predication and control flow masking in multiples of \p n channels.
116 group(unsigned n
, unsigned i
) const
118 assert(force_writemask_all
||
119 (n
<= dispatch_width() && i
< dispatch_width() / n
));
120 fs_builder bld
= *this;
121 bld
._dispatch_width
= n
;
127 * Alias for group() with width equal to eight.
130 half(unsigned i
) const
136 * Construct a builder with per-channel control flow execution masking
137 * disabled if \p b is true. If control flow execution masking is
138 * already disabled this has no effect.
141 exec_all(bool b
= true) const
143 fs_builder bld
= *this;
145 bld
.force_writemask_all
= true;
150 * Construct a builder with the given debug annotation info.
153 annotate(const char *str
, const void *ir
= NULL
) const
155 fs_builder bld
= *this;
156 bld
.annotation
.str
= str
;
157 bld
.annotation
.ir
= ir
;
162 * Get the SIMD width in use.
165 dispatch_width() const
167 return _dispatch_width
;
171 * Allocate a virtual register of natural vector size (one for this IR)
172 * and SIMD width. \p n gives the amount of space to allocate in
173 * dispatch_width units (which is just enough space for one logical
174 * component in this IR).
177 vgrf(enum brw_reg_type type
, unsigned n
= 1) const
179 assert(dispatch_width() <= 32);
182 return dst_reg(VGRF
, shader
->alloc
.allocate(
183 DIV_ROUND_UP(n
* type_sz(type
) * dispatch_width(),
187 return retype(null_reg_ud(), type
);
191 * Create a null register of floating type.
196 return dst_reg(retype(brw_null_vec(dispatch_width()),
197 BRW_REGISTER_TYPE_F
));
201 * Create a null register of signed integer type.
206 return dst_reg(retype(brw_null_vec(dispatch_width()),
207 BRW_REGISTER_TYPE_D
));
211 * Create a null register of unsigned integer type.
216 return dst_reg(retype(brw_null_vec(dispatch_width()),
217 BRW_REGISTER_TYPE_UD
));
221 * Get the mask of SIMD channels enabled by dispatch and not yet
222 * disabled by discard.
225 sample_mask_reg() const
227 if (shader
->stage
!= MESA_SHADER_FRAGMENT
) {
228 return src_reg(0xffff);
229 } else if (((brw_wm_prog_data
*)shader
->stage_prog_data
)->uses_kill
) {
230 return brw_flag_reg(0, 1);
232 return retype(brw_vec1_grf(1, 7), BRW_REGISTER_TYPE_UD
);
237 * Insert an instruction into the program.
240 emit(const instruction
&inst
) const
242 return emit(new(shader
->mem_ctx
) instruction(inst
));
246 * Create and insert a nullary control instruction into the program.
249 emit(enum opcode opcode
) const
251 return emit(instruction(opcode
, dispatch_width()));
255 * Create and insert a nullary instruction into the program.
258 emit(enum opcode opcode
, const dst_reg
&dst
) const
260 return emit(instruction(opcode
, dispatch_width(), dst
));
264 * Create and insert a unary instruction into the program.
267 emit(enum opcode opcode
, const dst_reg
&dst
, const src_reg
&src0
) const
270 case SHADER_OPCODE_RCP
:
271 case SHADER_OPCODE_RSQ
:
272 case SHADER_OPCODE_SQRT
:
273 case SHADER_OPCODE_EXP2
:
274 case SHADER_OPCODE_LOG2
:
275 case SHADER_OPCODE_SIN
:
276 case SHADER_OPCODE_COS
:
277 return fix_math_instruction(
278 emit(instruction(opcode
, dispatch_width(), dst
,
279 fix_math_operand(src0
))));
282 return emit(instruction(opcode
, dispatch_width(), dst
, src0
));
287 * Create and insert a binary instruction into the program.
290 emit(enum opcode opcode
, const dst_reg
&dst
, const src_reg
&src0
,
291 const src_reg
&src1
) const
294 case SHADER_OPCODE_POW
:
295 case SHADER_OPCODE_INT_QUOTIENT
:
296 case SHADER_OPCODE_INT_REMAINDER
:
297 return fix_math_instruction(
298 emit(instruction(opcode
, dispatch_width(), dst
,
299 fix_math_operand(src0
),
300 fix_math_operand(src1
))));
303 return emit(instruction(opcode
, dispatch_width(), dst
, src0
, src1
));
309 * Create and insert a ternary instruction into the program.
312 emit(enum opcode opcode
, const dst_reg
&dst
, const src_reg
&src0
,
313 const src_reg
&src1
, const src_reg
&src2
) const
317 case BRW_OPCODE_BFI2
:
320 return emit(instruction(opcode
, dispatch_width(), dst
,
321 fix_3src_operand(src0
),
322 fix_3src_operand(src1
),
323 fix_3src_operand(src2
)));
326 return emit(instruction(opcode
, dispatch_width(), dst
,
332 * Create and insert an instruction with a variable number of sources
336 emit(enum opcode opcode
, const dst_reg
&dst
, const src_reg srcs
[],
339 return emit(instruction(opcode
, dispatch_width(), dst
, srcs
, n
));
343 * Insert a preallocated instruction into the program.
346 emit(instruction
*inst
) const
348 assert(inst
->exec_size
<= 32);
349 assert(inst
->exec_size
== dispatch_width() ||
350 force_writemask_all
);
351 assert(_group
== 0 || _group
== 8);
353 inst
->force_sechalf
= (_group
== 8);
354 inst
->force_writemask_all
= force_writemask_all
;
355 inst
->annotation
= annotation
.str
;
356 inst
->ir
= annotation
.ir
;
359 static_cast<instruction
*>(cursor
)->insert_before(block
, inst
);
361 cursor
->insert_before(inst
);
367 * Select \p src0 if the comparison of both sources with the given
368 * conditional mod evaluates to true, otherwise select \p src1.
370 * Generally useful to get the minimum or maximum of two values.
373 emit_minmax(const dst_reg
&dst
, const src_reg
&src0
,
374 const src_reg
&src1
, brw_conditional_mod mod
) const
376 assert(mod
== BRW_CONDITIONAL_GE
|| mod
== BRW_CONDITIONAL_L
);
378 if (shader
->devinfo
->gen
>= 6) {
379 set_condmod(mod
, SEL(dst
, fix_unsigned_negate(src0
),
380 fix_unsigned_negate(src1
)));
382 CMP(null_reg_d(), src0
, src1
, mod
);
383 set_predicate(BRW_PREDICATE_NORMAL
,
384 SEL(dst
, src0
, src1
));
389 * Copy any live channel from \p src to the first channel of the result.
392 emit_uniformize(const src_reg
&src
) const
394 /* FIXME: We use a vector chan_index and dst to allow constant and
395 * copy propagration to move result all the way into the consuming
396 * instruction (typically a surface index or sampler index for a
397 * send). This uses 1 or 3 extra hw registers in 16 or 32 wide
398 * dispatch. Once we teach const/copy propagation about scalars we
399 * should go back to scalar destinations here.
401 const fs_builder ubld
= exec_all();
402 const dst_reg chan_index
= vgrf(BRW_REGISTER_TYPE_UD
);
403 const dst_reg dst
= vgrf(src
.type
);
405 ubld
.emit(SHADER_OPCODE_FIND_LIVE_CHANNEL
, chan_index
);
406 ubld
.emit(SHADER_OPCODE_BROADCAST
, dst
, src
, component(chan_index
, 0));
408 return src_reg(component(dst
, 0));
412 * Assorted arithmetic ops.
417 op(const dst_reg &dst, const src_reg &src0) const \
419 return emit(BRW_OPCODE_##op, dst, src0); \
424 op(const dst_reg &dst, const src_reg &src0, const src_reg &src1) const \
426 return emit(BRW_OPCODE_##op, dst, src0, src1); \
429 #define ALU2_ACC(op) \
431 op(const dst_reg &dst, const src_reg &src0, const src_reg &src1) const \
433 instruction *inst = emit(BRW_OPCODE_##op, dst, src0, src1); \
434 inst->writes_accumulator = true; \
440 op(const dst_reg &dst, const src_reg &src0, const src_reg &src1, \
441 const src_reg &src2) const \
443 return emit(BRW_OPCODE_##op, dst, src0, src1, src2); \
496 * CMP: Sets the low bit of the destination channels with the result
497 * of the comparison, while the upper bits are undefined, and updates
498 * the flag register with the packed 16 bits of the result.
501 CMP(const dst_reg
&dst
, const src_reg
&src0
, const src_reg
&src1
,
502 brw_conditional_mod condition
) const
504 /* Take the instruction:
506 * CMP null<d> src0<f> src1<f>
508 * Original gen4 does type conversion to the destination type
509 * before comparison, producing garbage results for floating
512 * The destination type doesn't matter on newer generations,
513 * so we set the type to match src0 so we can compact the
516 return set_condmod(condition
,
517 emit(BRW_OPCODE_CMP
, retype(dst
, src0
.type
),
518 fix_unsigned_negate(src0
),
519 fix_unsigned_negate(src1
)));
523 * Gen4 predicated IF.
526 IF(brw_predicate predicate
) const
528 return set_predicate(predicate
, emit(BRW_OPCODE_IF
));
532 * Emit a linear interpolation instruction.
535 LRP(const dst_reg
&dst
, const src_reg
&x
, const src_reg
&y
,
536 const src_reg
&a
) const
538 if (shader
->devinfo
->gen
>= 6) {
539 /* The LRP instruction actually does op1 * op0 + op2 * (1 - op0), so
540 * we need to reorder the operands.
542 return emit(BRW_OPCODE_LRP
, dst
, a
, y
, x
);
545 /* We can't use the LRP instruction. Emit x*(1-a) + y*a. */
546 const dst_reg y_times_a
= vgrf(dst
.type
);
547 const dst_reg one_minus_a
= vgrf(dst
.type
);
548 const dst_reg x_times_one_minus_a
= vgrf(dst
.type
);
550 MUL(y_times_a
, y
, a
);
551 ADD(one_minus_a
, negate(a
), src_reg(1.0f
));
552 MUL(x_times_one_minus_a
, x
, src_reg(one_minus_a
));
553 return ADD(dst
, src_reg(x_times_one_minus_a
), src_reg(y_times_a
));
558 * Collect a number of registers in a contiguous range of registers.
561 LOAD_PAYLOAD(const dst_reg
&dst
, const src_reg
*src
,
562 unsigned sources
, unsigned header_size
) const
564 instruction
*inst
= emit(SHADER_OPCODE_LOAD_PAYLOAD
, dst
, src
, sources
);
565 inst
->header_size
= header_size
;
566 inst
->regs_written
= header_size
+
567 (sources
- header_size
) * (dispatch_width() / 8);
572 backend_shader
*shader
;
576 * Workaround for negation of UD registers. See comment in
577 * fs_generator::generate_code() for more details.
580 fix_unsigned_negate(const src_reg
&src
) const
582 if (src
.type
== BRW_REGISTER_TYPE_UD
&&
584 dst_reg temp
= vgrf(BRW_REGISTER_TYPE_UD
);
586 return src_reg(temp
);
593 * Workaround for source register modes not supported by the ternary
594 * instruction encoding.
597 fix_3src_operand(const src_reg
&src
) const
599 if (src
.file
== VGRF
|| src
.file
== UNIFORM
|| src
.stride
> 1) {
602 dst_reg expanded
= vgrf(src
.type
);
609 * Workaround for source register modes not supported by the math
613 fix_math_operand(const src_reg
&src
) const
615 /* Can't do hstride == 0 args on gen6 math, so expand it out. We
616 * might be able to do better by doing execsize = 1 math and then
617 * expanding that result out, but we would need to be careful with
620 * Gen6 hardware ignores source modifiers (negate and abs) on math
621 * instructions, so we also move to a temp to set those up.
623 * Gen7 relaxes most of the above restrictions, but still can't use IMM
626 if ((shader
->devinfo
->gen
== 6 &&
627 (src
.file
== IMM
|| src
.file
== UNIFORM
||
628 src
.abs
|| src
.negate
)) ||
629 (shader
->devinfo
->gen
== 7 && src
.file
== IMM
)) {
630 const dst_reg tmp
= vgrf(src
.type
);
639 * Workaround other weirdness of the math instruction.
642 fix_math_instruction(instruction
*inst
) const
644 if (shader
->devinfo
->gen
< 6) {
646 inst
->mlen
= inst
->sources
* dispatch_width() / 8;
648 if (inst
->sources
> 1) {
649 /* From the Ironlake PRM, Volume 4, Part 1, Section 6.1.13
652 * "Operand0[7]. For the INT DIV functions, this operand is the
655 * "Operand1[7]. For the INT DIV functions, this operand is the
658 const bool is_int_div
= inst
->opcode
!= SHADER_OPCODE_POW
;
659 const fs_reg src0
= is_int_div
? inst
->src
[1] : inst
->src
[0];
660 const fs_reg src1
= is_int_div
? inst
->src
[0] : inst
->src
[1];
662 inst
->resize_sources(1);
665 at(block
, inst
).MOV(fs_reg(MRF
, inst
->base_mrf
+ 1, src1
.type
),
676 unsigned _dispatch_width
;
678 bool force_writemask_all
;
680 /** Debug annotation info. */