src/panfrost/bifrost/bi_pack.c - platform/external/mesa3d - Git at Google

 /*
  * Copyright (C) 2020 Collabora, Ltd.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the "Software"),
  * to deal in the Software without restriction, including without limitation
  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  * and/or sell copies of the Software, and to permit persons to whom the
  * Software is furnished to do so, subject to the following conditions:
  *
  * The above copyright notice and this permission notice (including the next
  * paragraph) shall be included in all copies or substantial portions of the
  * Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  * SOFTWARE.
  */

 #include "compiler.h"

 #define RETURN_PACKED(str) { \
         uint64_t temp = 0; \
         memcpy(&temp, &str, sizeof(str)); \
         return temp; \
 }

 /* This file contains the final passes of the compiler. Running after
  * scheduling and RA, the IR is now finalized, so we need to emit it to actual
  * bits on the wire (as well as fixup branches) */

 static uint64_t
 bi_pack_header(bi_clause *clause, bi_clause *next)
 {
         struct bifrost_header header = {
                 /* stub */
                 .no_end_of_shader = (next != NULL),
         };

         uint64_t u = 0;
         memcpy(&u, &header, sizeof(header));
         return u;
 }

 /* Represents the assignment of ports for a given bundle */

 struct bi_registers {
         /* Register to assign to each port */
         unsigned port[4];

         /* Read ports can be disabled */
         bool enabled[2];

         /* Should we write FMA? what about ADD? If only a single port is
          * enabled it is in port 2, else ADD/FMA is 2/3 respectively */
         bool write_fma, write_add;

         /* Should we read with port 3? */
         bool read_port3;

         /* Packed uniform/constant */
         unsigned uniform_constant;

         /* Whether writes are actually for the last instruction */
         bool first_instruction;
 };

 /* Assigns a port for reading, before anything is written */

 static void
 bi_assign_port_read(struct bi_registers *regs, unsigned src)
 {
         /* We only assign for registers */
         if (!(src & BIR_INDEX_REGISTER))
                 return;

         unsigned reg = src & ~BIR_INDEX_REGISTER;

         /* Check if we already assigned the port */
         for (unsigned i = 0; i <= 1; ++i) {
                 if (regs->port[i] == reg && regs->enabled[i])
                         return;
         }

         if (regs->port[3] == reg && regs->read_port3)
                 return;

         /* Assign it now */

         for (unsigned i = 0; i <= 1; ++i) {
                 if (!regs->enabled[i]) {
                         regs->port[i] = reg;
                         regs->enabled[i] = true;
                         return;
                 }
         }

         if (!regs->read_port3) {
                 regs->port[3] = reg;
                 regs->read_port3 = true;
         }
 }

 static struct bi_registers
 bi_assign_ports(bi_bundle now, bi_bundle prev)
 {
         struct bi_registers regs = { 0 };

         /* First, assign reads */

         if (now.fma)
                 bi_foreach_src(now.fma, src)
                         bi_assign_port_read(&regs, now.fma->src[src]);

         if (now.add)
                 bi_foreach_src(now.add, src)
                         bi_assign_port_read(&regs, now.add->src[src]);

         /* Next, assign writes */

         if (prev.fma && prev.fma->dest & BIR_INDEX_REGISTER) {
                 regs.port[2] = prev.fma->dest & ~BIR_INDEX_REGISTER;
                 regs.write_fma = true;
         }

         if (prev.add && prev.add->dest & BIR_INDEX_REGISTER) {
                 unsigned r = prev.add->dest & ~BIR_INDEX_REGISTER;

                 if (regs.write_fma) {
                         /* Scheduler constraint: cannot read 3 and write 2 */
                         assert(!regs.read_port3);
                         regs.port[3] = r;
                 } else {
                         regs.port[2] = r;
                 }

                 regs.write_add = true;
         }

         /* Finally, ensure port 1 > port 0 for the 63-x trick to function */

         if (regs.enabled[0] && regs.enabled[1] && regs.port[1] < regs.port[0]) {
                 unsigned temp = regs.port[0];
                 regs.port[0] = regs.port[1];
                 regs.port[1] = temp;
         }

         return regs;
 }

 /* Determines the register control field, ignoring the first? flag */

 static enum bifrost_reg_control
 bi_pack_register_ctrl_lo(struct bi_registers r)
 {
         if (r.write_fma) {
                 if (r.write_add) {
                         assert(!r.read_port3);
                         return BIFROST_WRITE_ADD_P2_FMA_P3;
                 } else {
                         if (r.read_port3)
                                 return BIFROST_WRITE_FMA_P2_READ_P3;
                         else
                                 return BIFROST_WRITE_FMA_P2;
                 }
         } else if (r.write_add) {
                 if (r.read_port3)
                         return BIFROST_WRITE_ADD_P2_READ_P3;
                 else
                         return BIFROST_WRITE_ADD_P2;
         } else if (r.read_port3)
                 return BIFROST_READ_P3;
         else
                 return BIFROST_REG_NONE;
 }

 /* Ditto but account for the first? flag this time */

 static enum bifrost_reg_control
 bi_pack_register_ctrl(struct bi_registers r)
 {
         enum bifrost_reg_control ctrl = bi_pack_register_ctrl_lo(r);

         if (r.first_instruction) {
                 if (ctrl == BIFROST_REG_NONE)
                         ctrl = BIFROST_FIRST_NONE;
                 else
                         ctrl |= BIFROST_FIRST_NONE;
         }

         return ctrl;
 }

 static uint64_t
 bi_pack_registers(struct bi_registers regs)
 {
         enum bifrost_reg_control ctrl = bi_pack_register_ctrl(regs);
         struct bifrost_regs s;
         uint64_t packed = 0;

         if (regs.enabled[1]) {
                 /* Gotta save that bit!~ Required by the 63-x trick */
                 assert(regs.port[1] > regs.port[0]);
                 assert(regs.enabled[0]);

                 /* Do the 63-x trick, see docs/disasm */
                 if (regs.port[0] > 31) {
                         regs.port[0] = 63 - regs.port[0];
                         regs.port[1] = 63 - regs.port[1];
                 }

                 assert(regs.port[0] <= 31);
                 assert(regs.port[1] <= 63);

                 s.ctrl = ctrl;
                 s.reg1 = regs.port[1];
                 s.reg0 = regs.port[0];
         } else {
                 /* Port 1 disabled, so set to zero and use port 1 for ctrl */
                 s.reg1 = ctrl << 2;

                 if (regs.enabled[0]) {
                         /* Bit 0 upper bit of port 0 */
                         s.reg1 |= (regs.port[0] >> 5);

                         /* Rest of port 0 in usual spot */
                         s.reg0 = (regs.port[0] & 0b11111);
                 } else {
                         /* Bit 1 set if port 0 also disabled */
                         s.reg1 |= (1 << 1);
                 }
         }

         s.reg3 = regs.port[3];
         s.reg2 = regs.port[2];
         s.uniform_const = regs.uniform_constant;

         memcpy(&packed, &s, sizeof(s));
         return packed;
 }

 static enum bifrost_packed_src
 bi_get_src_reg_port(struct bi_registers *regs, unsigned src)
 {
         unsigned reg = src & ~BIR_INDEX_REGISTER;

         if (regs->port[0] == reg && regs->enabled[0])
                 return BIFROST_SRC_PORT0;
         else if (regs->port[1] == reg && regs->enabled[1])
                 return BIFROST_SRC_PORT1;
         else if (regs->port[3] == reg && regs->read_port3)
                 return BIFROST_SRC_PORT3;
         else
                 unreachable("Tried to access register with no port");
 }

 static enum bifrost_packed_src
 bi_get_fma_src(bi_instruction *ins, struct bi_registers *regs, unsigned s)
 {
         unsigned src = ins->src[s];

         if (src & BIR_INDEX_REGISTER)
                 return bi_get_src_reg_port(regs, src);
         else if (src & BIR_INDEX_ZERO)
                 return BIFROST_SRC_STAGE;
         else if (src & BIR_INDEX_PASS)
                 return src & ~BIR_INDEX_PASS;
         else
                 unreachable("Unknown src in FMA");
 }

 static unsigned
 bi_pack_fma_fma(bi_instruction *ins, struct bi_registers *regs)
 {
         /* (-a)(-b) = ab, so we only need one negate bit */
         bool negate_mul = ins->src_neg[0] ^ ins->src_neg[1];

         struct bifrost_fma_fma pack = {
                 .src0 = bi_get_fma_src(ins, regs, 0),
                 .src1 = bi_get_fma_src(ins, regs, 1),
                 .src2 = bi_get_fma_src(ins, regs, 2),
                 .src0_abs = ins->src_abs[0],
                 .src1_abs = ins->src_abs[1],
                 .src2_abs = ins->src_abs[2],
                 .src0_neg = negate_mul,
                 .src2_neg = ins->src_neg[2],
                 .op = BIFROST_FMA_OP_FMA
         };

         RETURN_PACKED(pack);
 }

 static unsigned
 bi_pack_fma(bi_clause *clause, bi_bundle bundle, struct bi_registers *regs)
 {
         if (!bundle.fma)
                 return BIFROST_FMA_NOP;

         switch (bundle.fma->type) {
         case BI_ADD:
         case BI_CMP:
         case BI_BITWISE:
         case BI_CONVERT:
         case BI_CSEL:
 		return BIFROST_FMA_NOP;
         case BI_FMA:
                 return bi_pack_fma_fma(bundle.fma, regs);
         case BI_FREXP:
         case BI_ISUB:
         case BI_MINMAX:
         case BI_MOV:
         case BI_SHIFT:
         case BI_SWIZZLE:
         case BI_ROUND:
 		return BIFROST_FMA_NOP;
         default:
                 unreachable("Cannot encode class as FMA");
         }
 }

 static unsigned
 bi_pack_add(bi_clause *clause, bi_bundle bundle, struct bi_registers *regs)
 {
         /* TODO */
         return BIFROST_ADD_NOP;
 }

 struct bi_packed_bundle {
         uint64_t lo;
         uint64_t hi;
 };

 static struct bi_packed_bundle
 bi_pack_bundle(bi_clause *clause, bi_bundle bundle, bi_bundle prev, bool first_bundle)
 {
         struct bi_registers regs = bi_assign_ports(bundle, prev);
         regs.first_instruction = first_bundle;

         uint64_t reg = bi_pack_registers(regs);
         uint64_t fma = bi_pack_fma(clause, bundle, &regs);
         uint64_t add = bi_pack_add(clause, bundle, &regs);

         struct bi_packed_bundle packed = {
                 .lo = reg | (fma << 35) | ((add & 0b111111) << 58),
                 .hi = add >> 6
         };

         return packed;
 }

 static void
 bi_pack_clause(bi_context *ctx, bi_clause *clause, bi_clause *next,
                 struct util_dynarray *emission)
 {
         struct bi_packed_bundle ins_1 = bi_pack_bundle(clause, clause->bundles[0], clause->bundles[0], true);
         assert(clause->bundle_count == 1);

         struct bifrost_fmt1 quad_1 = {
                 .tag = BIFROST_FMT1_FINAL,
                 .header = bi_pack_header(clause, next),
                 .ins_1 = ins_1.lo,
                 .ins_2 = ins_1.hi & ((1 << 11) - 1),
                 .ins_0 = (ins_1.hi >> 11) & 0b111,
         };

         util_dynarray_append(emission, struct bifrost_fmt1, quad_1);
 }

 static bi_clause *
 bi_next_clause(bi_context *ctx, pan_block *block, bi_clause *clause)
 {
         /* Try the next clause in this block */
         if (clause->link.next != &((bi_block *) block)->clauses)
                 return list_first_entry(&(clause->link), bi_clause, link);

         /* Try the next block, or the one after that if it's empty, etc .*/
         pan_block *next_block = pan_next_block(block);

         bi_foreach_block_from(ctx, next_block, block) {
                 bi_block *blk = (bi_block *) block;

                 if (!list_is_empty(&blk->clauses))
                         return list_first_entry(&(blk->clauses), bi_clause, link);
         }

         return NULL;
 }

 void
 bi_pack(bi_context *ctx, struct util_dynarray *emission)
 {
         util_dynarray_init(emission, NULL);

         bi_foreach_block(ctx, _block) {
                 bi_block *block = (bi_block *) _block;

                 bi_foreach_clause_in_block(block, clause) {
                         bi_clause *next = bi_next_clause(ctx, _block, clause);
                         bi_pack_clause(ctx, clause, next, emission);
                 }
         }
 }
	/*
	* Copyright (C) 2020 Collabora, Ltd.
	*
	* Permission is hereby granted, free of charge, to any person obtaining a
	* copy of this software and associated documentation files (the "Software"),
	* to deal in the Software without restriction, including without limitation
	* the rights to use, copy, modify, merge, publish, distribute, sublicense,
	* and/or sell copies of the Software, and to permit persons to whom the
	* Software is furnished to do so, subject to the following conditions:
	*
	* The above copyright notice and this permission notice (including the next
	* paragraph) shall be included in all copies or substantial portions of the
	* Software.
	*
	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
	* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
	* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
	* SOFTWARE.
	*/

	#include "compiler.h"

	#define RETURN_PACKED(str) { \
	uint64_t temp = 0; \
	memcpy(&temp, &str, sizeof(str)); \
	return temp; \
	}

	/* This file contains the final passes of the compiler. Running after
	* scheduling and RA, the IR is now finalized, so we need to emit it to actual
	* bits on the wire (as well as fixup branches) */

	static uint64_t
	bi_pack_header(bi_clause clause, bi_clause next)
	{
	struct bifrost_header header = {
	/* stub */
	.no_end_of_shader = (next != NULL),
	};

	uint64_t u = 0;
	memcpy(&u, &header, sizeof(header));
	return u;
	}

	/* Represents the assignment of ports for a given bundle */

	struct bi_registers {
	/* Register to assign to each port */
	unsigned port[4];

	/* Read ports can be disabled */
	bool enabled[2];

	/* Should we write FMA? what about ADD? If only a single port is
	* enabled it is in port 2, else ADD/FMA is 2/3 respectively */
	bool write_fma, write_add;

	/* Should we read with port 3? */
	bool read_port3;

	/* Packed uniform/constant */
	unsigned uniform_constant;

	/* Whether writes are actually for the last instruction */
	bool first_instruction;
	};

	/* Assigns a port for reading, before anything is written */

	static void
	bi_assign_port_read(struct bi_registers *regs, unsigned src)
	{
	/* We only assign for registers */
	if (!(src & BIR_INDEX_REGISTER))
	return;

	unsigned reg = src & ~BIR_INDEX_REGISTER;

	/* Check if we already assigned the port */
	for (unsigned i = 0; i <= 1; ++i) {
	if (regs->port[i] == reg && regs->enabled[i])
	return;
	}

	if (regs->port[3] == reg && regs->read_port3)
	return;

	/* Assign it now */

	for (unsigned i = 0; i <= 1; ++i) {
	if (!regs->enabled[i]) {
	regs->port[i] = reg;
	regs->enabled[i] = true;
	return;
	}
	}

	if (!regs->read_port3) {
	regs->port[3] = reg;
	regs->read_port3 = true;
	}
	}

	static struct bi_registers
	bi_assign_ports(bi_bundle now, bi_bundle prev)
	{
	struct bi_registers regs = { 0 };

	/* First, assign reads */

	if (now.fma)
	bi_foreach_src(now.fma, src)
	bi_assign_port_read(&regs, now.fma->src[src]);

	if (now.add)
	bi_foreach_src(now.add, src)
	bi_assign_port_read(&regs, now.add->src[src]);

	/* Next, assign writes */

	if (prev.fma && prev.fma->dest & BIR_INDEX_REGISTER) {
	regs.port[2] = prev.fma->dest & ~BIR_INDEX_REGISTER;
	regs.write_fma = true;
	}

	if (prev.add && prev.add->dest & BIR_INDEX_REGISTER) {
	unsigned r = prev.add->dest & ~BIR_INDEX_REGISTER;

	if (regs.write_fma) {
	/* Scheduler constraint: cannot read 3 and write 2 */
	assert(!regs.read_port3);
	regs.port[3] = r;
	} else {
	regs.port[2] = r;
	}

	regs.write_add = true;
	}

	/* Finally, ensure port 1 > port 0 for the 63-x trick to function */

	if (regs.enabled[0] && regs.enabled[1] && regs.port[1] < regs.port[0]) {
	unsigned temp = regs.port[0];
	regs.port[0] = regs.port[1];
	regs.port[1] = temp;
	}

	return regs;
	}

	/* Determines the register control field, ignoring the first? flag */

	static enum bifrost_reg_control
	bi_pack_register_ctrl_lo(struct bi_registers r)
	{
	if (r.write_fma) {
	if (r.write_add) {
	assert(!r.read_port3);
	return BIFROST_WRITE_ADD_P2_FMA_P3;
	} else {
	if (r.read_port3)
	return BIFROST_WRITE_FMA_P2_READ_P3;
	else
	return BIFROST_WRITE_FMA_P2;
	}
	} else if (r.write_add) {
	if (r.read_port3)
	return BIFROST_WRITE_ADD_P2_READ_P3;
	else
	return BIFROST_WRITE_ADD_P2;
	} else if (r.read_port3)
	return BIFROST_READ_P3;
	else
	return BIFROST_REG_NONE;
	}

	/* Ditto but account for the first? flag this time */

	static enum bifrost_reg_control
	bi_pack_register_ctrl(struct bi_registers r)
	{
	enum bifrost_reg_control ctrl = bi_pack_register_ctrl_lo(r);

	if (r.first_instruction) {
	if (ctrl == BIFROST_REG_NONE)
	ctrl = BIFROST_FIRST_NONE;
	else
	ctrl \|= BIFROST_FIRST_NONE;
	}

	return ctrl;
	}

	static uint64_t
	bi_pack_registers(struct bi_registers regs)
	{
	enum bifrost_reg_control ctrl = bi_pack_register_ctrl(regs);
	struct bifrost_regs s;
	uint64_t packed = 0;

	if (regs.enabled[1]) {
	/* Gotta save that bit!~ Required by the 63-x trick */
	assert(regs.port[1] > regs.port[0]);
	assert(regs.enabled[0]);

	/* Do the 63-x trick, see docs/disasm */
	if (regs.port[0] > 31) {
	regs.port[0] = 63 - regs.port[0];
	regs.port[1] = 63 - regs.port[1];
	}

	assert(regs.port[0] <= 31);
	assert(regs.port[1] <= 63);

	s.ctrl = ctrl;
	s.reg1 = regs.port[1];
	s.reg0 = regs.port[0];
	} else {
	/* Port 1 disabled, so set to zero and use port 1 for ctrl */
	s.reg1 = ctrl << 2;

	if (regs.enabled[0]) {
	/* Bit 0 upper bit of port 0 */
	s.reg1 \|= (regs.port[0] >> 5);

	/* Rest of port 0 in usual spot */
	s.reg0 = (regs.port[0] & 0b11111);
	} else {
	/* Bit 1 set if port 0 also disabled */
	s.reg1 \|= (1 << 1);
	}
	}

	s.reg3 = regs.port[3];
	s.reg2 = regs.port[2];
	s.uniform_const = regs.uniform_constant;

	memcpy(&packed, &s, sizeof(s));
	return packed;
	}

	static enum bifrost_packed_src
	bi_get_src_reg_port(struct bi_registers *regs, unsigned src)
	{
	unsigned reg = src & ~BIR_INDEX_REGISTER;

	if (regs->port[0] == reg && regs->enabled[0])
	return BIFROST_SRC_PORT0;
	else if (regs->port[1] == reg && regs->enabled[1])
	return BIFROST_SRC_PORT1;
	else if (regs->port[3] == reg && regs->read_port3)
	return BIFROST_SRC_PORT3;
	else
	unreachable("Tried to access register with no port");
	}

	static enum bifrost_packed_src
	bi_get_fma_src(bi_instruction ins, struct bi_registers regs, unsigned s)
	{
	unsigned src = ins->src[s];

	if (src & BIR_INDEX_REGISTER)
	return bi_get_src_reg_port(regs, src);
	else if (src & BIR_INDEX_ZERO)
	return BIFROST_SRC_STAGE;
	else if (src & BIR_INDEX_PASS)
	return src & ~BIR_INDEX_PASS;
	else
	unreachable("Unknown src in FMA");
	}

	static unsigned
	bi_pack_fma_fma(bi_instruction ins, struct bi_registers regs)
	{
	/* (-a)(-b) = ab, so we only need one negate bit */
	bool negate_mul = ins->src_neg[0] ^ ins->src_neg[1];

	struct bifrost_fma_fma pack = {
	.src0 = bi_get_fma_src(ins, regs, 0),
	.src1 = bi_get_fma_src(ins, regs, 1),
	.src2 = bi_get_fma_src(ins, regs, 2),
	.src0_abs = ins->src_abs[0],
	.src1_abs = ins->src_abs[1],
	.src2_abs = ins->src_abs[2],
	.src0_neg = negate_mul,
	.src2_neg = ins->src_neg[2],
	.op = BIFROST_FMA_OP_FMA
	};

	RETURN_PACKED(pack);
	}

	static unsigned
	bi_pack_fma(bi_clause clause, bi_bundle bundle, struct bi_registers regs)
	{
	if (!bundle.fma)
	return BIFROST_FMA_NOP;

	switch (bundle.fma->type) {
	case BI_ADD:
	case BI_CMP:
	case BI_BITWISE:
	case BI_CONVERT:
	case BI_CSEL:
	return BIFROST_FMA_NOP;
	case BI_FMA:
	return bi_pack_fma_fma(bundle.fma, regs);
	case BI_FREXP:
	case BI_ISUB:
	case BI_MINMAX:
	case BI_MOV:
	case BI_SHIFT:
	case BI_SWIZZLE:
	case BI_ROUND:
	return BIFROST_FMA_NOP;
	default:
	unreachable("Cannot encode class as FMA");
	}
	}

	static unsigned
	bi_pack_add(bi_clause clause, bi_bundle bundle, struct bi_registers regs)
	{
	/* TODO */
	return BIFROST_ADD_NOP;
	}

	struct bi_packed_bundle {
	uint64_t lo;
	uint64_t hi;
	};

	static struct bi_packed_bundle
	bi_pack_bundle(bi_clause *clause, bi_bundle bundle, bi_bundle prev, bool first_bundle)
	{
	struct bi_registers regs = bi_assign_ports(bundle, prev);
	regs.first_instruction = first_bundle;

	uint64_t reg = bi_pack_registers(regs);
	uint64_t fma = bi_pack_fma(clause, bundle, &regs);
	uint64_t add = bi_pack_add(clause, bundle, &regs);

	struct bi_packed_bundle packed = {
	.lo = reg \| (fma << 35) \| ((add & 0b111111) << 58),
	.hi = add >> 6
	};

	return packed;
	}

	static void
	bi_pack_clause(bi_context ctx, bi_clause clause, bi_clause *next,
	struct util_dynarray *emission)
	{
	struct bi_packed_bundle ins_1 = bi_pack_bundle(clause, clause->bundles[0], clause->bundles[0], true);
	assert(clause->bundle_count == 1);

	struct bifrost_fmt1 quad_1 = {
	.tag = BIFROST_FMT1_FINAL,
	.header = bi_pack_header(clause, next),
	.ins_1 = ins_1.lo,
	.ins_2 = ins_1.hi & ((1 << 11) - 1),
	.ins_0 = (ins_1.hi >> 11) & 0b111,
	};

	util_dynarray_append(emission, struct bifrost_fmt1, quad_1);
	}

	static bi_clause *
	bi_next_clause(bi_context ctx, pan_block block, bi_clause *clause)
	{
	/* Try the next clause in this block */
	if (clause->link.next != &((bi_block *) block)->clauses)
	return list_first_entry(&(clause->link), bi_clause, link);

	/* Try the next block, or the one after that if it's empty, etc .*/
	pan_block *next_block = pan_next_block(block);

	bi_foreach_block_from(ctx, next_block, block) {
	bi_block blk = (bi_block ) block;

	if (!list_is_empty(&blk->clauses))
	return list_first_entry(&(blk->clauses), bi_clause, link);
	}

	return NULL;
	}

	void
	bi_pack(bi_context ctx, struct util_dynarray emission)
	{
	util_dynarray_init(emission, NULL);

	bi_foreach_block(ctx, _block) {
	bi_block block = (bi_block ) _block;

	bi_foreach_clause_in_block(block, clause) {
	bi_clause *next = bi_next_clause(ctx, _block, clause);
	bi_pack_clause(ctx, clause, next, emission);
	}
	}
	}