/*
 * Copyright (C) 2018 Jonathan Marek <jonathan@marek.ca>
 *
 * 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.
 *
 * Authors:
 *    Jonathan Marek <jonathan@marek.ca>
 */

#include <stdlib.h>
#include <stdint.h>
#include <stdio.h>
#include <string.h>
#include <assert.h>

#include "ir2.h"
#include "fd2_program.h"
#include "instr-a2xx.h"

enum ir2_src_type {
	IR2_SRC_SSA,
	IR2_SRC_REG,
	IR2_SRC_INPUT,
	IR2_SRC_CONST,
};

struct ir2_src {
	/* num can mean different things
	 *   ssa: index of instruction
	 *   reg: index in ctx->reg array
	 *   input: index in ctx->input array
	 *   const: constant index (C0, C1, etc)
	 */
	uint16_t num;
	uint8_t swizzle;
	enum ir2_src_type type : 2;
	uint8_t abs : 1;
	uint8_t negate : 1;
	uint8_t : 4;
};

struct ir2_reg_component {
	uint8_t c : 3; /* assigned x/y/z/w (7=dont write, for fetch instr) */
	bool alloc : 1; /* is it currently allocated */
	uint8_t ref_count; /* for ra */
};

struct ir2_reg {
	uint8_t idx; /* assigned hardware register */
	uint8_t ncomp;

	uint8_t loop_depth;
	bool initialized;
	/* block_idx to free on (-1 = free on ref_count==0) */
	int block_idx_free;
	struct ir2_reg_component comp[4];
};

struct ir2_instr {
	unsigned idx;

	unsigned block_idx;

	enum {
		IR2_NONE,
		IR2_FETCH,
		IR2_ALU,
		IR2_CF,
	} type : 2;

	/* instruction needs to be emitted (for scheduling) */
	bool need_emit : 1;

	/* predicate value - (usually) same for entire block */
	uint8_t pred : 2;

	/* src */
	uint8_t src_count;
	struct ir2_src src[4];

	/* dst */
	bool is_ssa;
	union {
		struct ir2_reg ssa;
		struct ir2_reg *reg;
	};

	/* type-specific */
	union {
		struct {
			instr_fetch_opc_t opc : 5;
			union {
				struct {
					uint8_t const_idx;
					uint8_t const_idx_sel;
				} vtx;
				struct {
					bool is_cube : 1;
					bool is_rect : 1;
					uint8_t samp_id;
				} tex;
			};
		} fetch;
		struct {
			/* store possible opcs, then we can choose vector/scalar instr */
			instr_scalar_opc_t scalar_opc : 6;
			instr_vector_opc_t vector_opc : 5;
			/* same as nir */
			uint8_t write_mask : 4;
			bool saturate : 1;

			/* export idx (-1 no export) */
			int8_t export;

			/* for scalarized 2 src instruction */
			uint8_t src1_swizzle;
		} alu;
		struct {
			/* jmp dst block_idx */
			uint8_t block_idx;
		} cf;
	};
};

struct ir2_sched_instr {
	uint32_t reg_state[8];
	struct ir2_instr *instr, *instr_s;
};

struct ir2_context {
	struct fd2_shader_stateobj *so;

	unsigned block_idx, pred_idx;
	uint8_t pred;
	bool block_has_jump[64];

	unsigned loop_last_block[64];
	unsigned loop_depth;

	nir_shader *nir;

	/* ssa index of position output */
	struct ir2_src position;

	/* to translate SSA ids to instruction ids */
	int16_t ssa_map[1024];

	struct ir2_shader_info *info;
	struct ir2_frag_linkage *f;

	int prev_export;

	/* RA state */
	struct ir2_reg* live_regs[64];
	uint32_t reg_state[256/32]; /* 64*4 bits */

	/* inputs */
	struct ir2_reg input[16 + 1]; /* 16 + param */

	/* non-ssa regs */
	struct ir2_reg reg[64];
	unsigned reg_count;

	struct ir2_instr instr[0x300];
	unsigned instr_count;

	struct ir2_sched_instr instr_sched[0x180];
	unsigned instr_sched_count;
};

void assemble(struct ir2_context *ctx, bool binning);

void ir2_nir_compile(struct ir2_context *ctx, bool binning);
bool ir2_nir_lower_scalar(nir_shader * shader);

void ra_count_refs(struct ir2_context *ctx);
void ra_reg(struct ir2_context *ctx, struct ir2_reg *reg, int force_idx,
	bool export, uint8_t export_writemask);
void ra_src_free(struct ir2_context *ctx, struct ir2_instr *instr);
void ra_block_free(struct ir2_context *ctx, unsigned block);

void cp_src(struct ir2_context *ctx);
void cp_export(struct ir2_context *ctx);

/* utils */
enum {
	IR2_SWIZZLE_Y = 1 << 0,
	IR2_SWIZZLE_Z = 2 << 0,
	IR2_SWIZZLE_W = 3 << 0,

	IR2_SWIZZLE_ZW = 2 << 0 | 2 << 2,

	IR2_SWIZZLE_YXW = 1 << 0 | 3 << 2 | 1 << 4,

	IR2_SWIZZLE_XXXX = 0 << 0 | 3 << 2 | 2 << 4 | 1 << 6,
	IR2_SWIZZLE_YYYY = 1 << 0 | 0 << 2 | 3 << 4 | 2 << 6,
	IR2_SWIZZLE_ZZZZ = 2 << 0 | 1 << 2 | 0 << 4 | 3 << 6,
	IR2_SWIZZLE_WWWW = 3 << 0 | 2 << 2 | 1 << 4 | 0 << 6,
	IR2_SWIZZLE_WYWW = 3 << 0 | 0 << 2 | 1 << 4 | 0 << 6,
	IR2_SWIZZLE_XYXY = 0 << 0 | 0 << 2 | 2 << 4 | 2 << 6,
	IR2_SWIZZLE_ZZXY = 2 << 0 | 1 << 2 | 2 << 4 | 2 << 6,
	IR2_SWIZZLE_YXZZ = 1 << 0 | 3 << 2 | 0 << 4 | 3 << 6,
};

#define compile_error(ctx, args...) ({ \
	printf(args); \
	assert(0); \
})

static inline struct ir2_src
ir2_src(uint16_t num, uint8_t swizzle, enum ir2_src_type type)
{
	return (struct ir2_src) {
		.num = num,
		.swizzle = swizzle,
		.type = type
	};
}

/* ir2_assemble uses it .. */
struct ir2_src ir2_zero(struct ir2_context *ctx);

#define ir2_foreach_instr(it, ctx) \
	for (struct ir2_instr *it = (ctx)->instr; ({ \
		while (it != &(ctx)->instr[(ctx)->instr_count] && it->type == IR2_NONE) it++; \
		 it != &(ctx)->instr[(ctx)->instr_count]; }); it++)

#define ir2_foreach_live_reg(it, ctx) \
	for (struct ir2_reg **__ptr = (ctx)->live_regs, *it; ({ \
		while (__ptr != &(ctx)->live_regs[64] && *__ptr == NULL) __ptr++; \
		 __ptr != &(ctx)->live_regs[64] ? (it=*__ptr) : NULL; }); it++)

#define ir2_foreach_avail(it) \
	for (struct ir2_instr **__instrp = avail, *it; \
		it = *__instrp,  __instrp != &avail[avail_count]; __instrp++)

#define ir2_foreach_src(it, instr) \
	for (struct ir2_src *it = instr->src; \
		 it != &instr->src[instr->src_count]; it++)

/* mask for register allocation
 * 64 registers with 4 components each = 256 bits
 */
/* typedef struct {
	uint64_t data[4];
} regmask_t; */

static inline bool mask_isset(uint32_t * mask, unsigned num)
{
	return ! !(mask[num / 32] & 1 << num % 32);
}

static inline void mask_set(uint32_t * mask, unsigned num)
{
	mask[num / 32] |= 1 << num % 32;
}

static inline void mask_unset(uint32_t * mask, unsigned num)
{
	mask[num / 32] &= ~(1 << num % 32);
}

static inline unsigned mask_reg(uint32_t * mask, unsigned num)
{
	return mask[num / 8] >> num % 8 * 4 & 0xf;
}

static inline bool is_export(struct ir2_instr *instr)
{
	return instr->type == IR2_ALU && instr->alu.export >= 0;
}

static inline instr_alloc_type_t export_buf(unsigned num)
{
	return num < 32 ? SQ_PARAMETER_PIXEL :
		num >= 62 ? SQ_POSITION : SQ_MEMORY;
}

/* component c for channel i */
static inline unsigned swiz_set(unsigned c, unsigned i)
{
	return ((c - i) & 3) << i * 2;
}

/* get swizzle in channel i */
static inline unsigned swiz_get(unsigned swiz, unsigned i)
{
	return ((swiz >> i * 2) + i) & 3;
}

static inline unsigned swiz_merge(unsigned swiz0, unsigned swiz1)
{
	unsigned swiz = 0;
	for (int i = 0; i < 4; i++)
		swiz |= swiz_set(swiz_get(swiz0, swiz_get(swiz1, i)), i);
	return swiz;
}

static inline void swiz_merge_p(uint8_t *swiz0, unsigned swiz1)
{
	unsigned swiz = 0;
	for (int i = 0; i < 4; i++)
		swiz |= swiz_set(swiz_get(*swiz0, swiz_get(swiz1, i)), i);
	*swiz0 = swiz;
}

static inline struct ir2_reg * get_reg(struct ir2_instr *instr)
{
	return instr->is_ssa ? &instr->ssa : instr->reg;
}

static inline struct ir2_reg *
get_reg_src(struct ir2_context *ctx, struct ir2_src *src)
{
	switch (src->type) {
	case IR2_SRC_INPUT:
		return &ctx->input[src->num];
	case IR2_SRC_SSA:
		return &ctx->instr[src->num].ssa;
	case IR2_SRC_REG:
		return &ctx->reg[src->num];
	default:
		return NULL;
	}
}

/* gets a ncomp value for the dst */
static inline unsigned dst_ncomp(struct ir2_instr *instr)
{
	if (instr->is_ssa)
		return instr->ssa.ncomp;

	if (instr->type == IR2_FETCH)
		return instr->reg->ncomp;

	assert(instr->type == IR2_ALU);

	unsigned ncomp = 0;
	for (int i = 0; i < instr->reg->ncomp; i++)
		ncomp += !!(instr->alu.write_mask & 1 << i);
	return ncomp;
}

/* gets a ncomp value for the src registers */
static inline unsigned src_ncomp(struct ir2_instr *instr)
{
	if (instr->type == IR2_FETCH) {
		switch (instr->fetch.opc) {
		case VTX_FETCH:
			return 1;
		case TEX_FETCH:
			return instr->fetch.tex.is_cube ? 3 : 2;
		case TEX_SET_TEX_LOD:
			return 1;
		default:
			assert(0);
		}
	}

	switch (instr->alu.scalar_opc) {
	case PRED_SETEs ... KILLONEs:
		return 1;
	default:
		break;
	}

	switch (instr->alu.vector_opc) {
	case DOT2ADDv:
		return 2;
	case DOT3v:
		return 3;
	case DOT4v:
	case CUBEv:
	case PRED_SETE_PUSHv:
		return 4;
	default:
		return dst_ncomp(instr);
	}
}