/*
 * Copyright 2010 Tom Stellard <tstellar@gmail.com>
 * SPDX-License-Identifier: MIT
 */

#include "radeon_compiler_util.h"

#include "r300_fragprog_swizzle.h"
#include "radeon_compiler.h"
#include "radeon_dataflow.h"

#include "util/u_math.h"
/**
 */
unsigned int
rc_swizzle_to_writemask(unsigned int swz)
{
   unsigned int mask = 0;
   unsigned int i;

   for (i = 0; i < 4; i++) {
      mask |= 1 << GET_SWZ(swz, i);
   }
   mask &= RC_MASK_XYZW;

   return mask;
}

rc_swizzle
get_swz(unsigned int swz, rc_swizzle idx)
{
   if (idx & 0x4)
      return idx;
   return GET_SWZ(swz, idx);
}

/**
 * The purpose of this function is to standardize the number channels used by
 * swizzles.  All swizzles regardless of what instruction they are a part of
 * should have 4 channels initialized with values.
 * @param channels The number of channels in initial_value that have a
 * meaningful value.
 * @return An initialized swizzle that has all of the unused channels set to
 * RC_SWIZZLE_UNUSED.
 */
unsigned int
rc_init_swizzle(unsigned int initial_value, unsigned int channels)
{
   unsigned int i;
   for (i = channels; i < 4; i++) {
      SET_SWZ(initial_value, i, RC_SWIZZLE_UNUSED);
   }
   return initial_value;
}

unsigned int
combine_swizzles4(unsigned int src, rc_swizzle swz_x, rc_swizzle swz_y, rc_swizzle swz_z,
                  rc_swizzle swz_w)
{
   unsigned int ret = 0;

   ret |= get_swz(src, swz_x);
   ret |= get_swz(src, swz_y) << 3;
   ret |= get_swz(src, swz_z) << 6;
   ret |= get_swz(src, swz_w) << 9;

   return ret;
}

unsigned int
combine_swizzles(unsigned int src, unsigned int swz)
{
   unsigned int ret = 0;

   ret |= get_swz(src, GET_SWZ(swz, RC_SWIZZLE_X));
   ret |= get_swz(src, GET_SWZ(swz, RC_SWIZZLE_Y)) << 3;
   ret |= get_swz(src, GET_SWZ(swz, RC_SWIZZLE_Z)) << 6;
   ret |= get_swz(src, GET_SWZ(swz, RC_SWIZZLE_W)) << 9;

   return ret;
}

/**
 * @param mask Must be either RC_MASK_X, RC_MASK_Y, RC_MASK_Z, or RC_MASK_W
 */
rc_swizzle
rc_mask_to_swizzle(unsigned int mask)
{
   switch (mask) {
   case RC_MASK_X:
      return RC_SWIZZLE_X;
   case RC_MASK_Y:
      return RC_SWIZZLE_Y;
   case RC_MASK_Z:
      return RC_SWIZZLE_Z;
   case RC_MASK_W:
      return RC_SWIZZLE_W;
   }
   return RC_SWIZZLE_UNUSED;
}

/* Reorder mask bits according to swizzle. */
unsigned
swizzle_mask(unsigned swizzle, unsigned mask)
{
   unsigned ret = 0;
   for (unsigned chan = 0; chan < 4; ++chan) {
      unsigned swz = GET_SWZ(swizzle, chan);
      if (swz < 4)
         ret |= GET_BIT(mask, swz) << chan;
   }
   return ret;
}

static unsigned int
srcs_need_rewrite(const struct rc_opcode_info *info)
{
   if (info->HasTexture) {
      return 0;
   }
   switch (info->Opcode) {
   case RC_OPCODE_DP2:
   case RC_OPCODE_DP3:
   case RC_OPCODE_DP4:
   case RC_OPCODE_DDX:
   case RC_OPCODE_DDY:
      return 0;
   default:
      return 1;
   }
}

/**
 * This function moves the old swizzles to new channels using the values
 * in the conversion swizzle. For example if the instruction writemask is
 * changed from x to y, then conversion_swizzle should be y___ and this
 * function will adjust the old argument swizzles (of the same instruction)
 * to the new channels, so x___ will become _x__, etc...
 *
 * @param old_swizzle The swizzle to change
 * @param conversion_swizzle Describes the conversion to perform on the swizzle
 * @return A new swizzle
 */
unsigned int
rc_adjust_channels(unsigned int old_swizzle, unsigned int conversion_swizzle)
{
   unsigned int i;
   unsigned int new_swizzle = rc_init_swizzle(RC_SWIZZLE_UNUSED, 0);
   for (i = 0; i < 4; i++) {
      unsigned int new_chan = get_swz(conversion_swizzle, i);
      if (new_chan == RC_SWIZZLE_UNUSED) {
         continue;
      }
      SET_SWZ(new_swizzle, new_chan, GET_SWZ(old_swizzle, i));
   }
   return new_swizzle;
}

static unsigned int
rewrite_writemask(unsigned int old_mask, unsigned int conversion_swizzle)
{
   unsigned int new_mask = 0;
   unsigned int i;

   for (i = 0; i < 4; i++) {
      if (!GET_BIT(old_mask, i) || GET_SWZ(conversion_swizzle, i) == RC_SWIZZLE_UNUSED) {
         continue;
      }
      new_mask |= (1 << GET_SWZ(conversion_swizzle, i));
   }

   return new_mask;
}

/**
 * This function rewrites the writemask of sub and adjusts the swizzles
 * of all its source registers based on the conversion_swizzle.
 * conversion_swizzle represents a mapping of the old writemask to the
 * new writemask.  For a detailed description of how conversion swizzles
 * work see rc_rewrite_swizzle().
 */
void
rc_pair_rewrite_writemask(struct rc_pair_sub_instruction *sub, unsigned int conversion_swizzle)
{
   const struct rc_opcode_info *info = rc_get_opcode_info(sub->Opcode);
   unsigned int i;

   sub->WriteMask = rewrite_writemask(sub->WriteMask, conversion_swizzle);

   if (!srcs_need_rewrite(info)) {
      return;
   }

   for (i = 0; i < info->NumSrcRegs; i++) {
      sub->Arg[i].Swizzle = rc_adjust_channels(sub->Arg[i].Swizzle, conversion_swizzle);
   }
}

static void
normal_rewrite_writemask_cb(void *userdata, struct rc_instruction *inst,
                            struct rc_src_register *src)
{
   unsigned int *conversion_swizzle = (unsigned int *)userdata;
   src->Swizzle = rc_adjust_channels(src->Swizzle, *conversion_swizzle);

   /* Per-channel negates are possible in vertex shaders,
    * so we need to rewrite it properly as well. */
   unsigned int new_negate = 0;
   for (unsigned int i = 0; i < 4; i++) {
      unsigned int new_chan = get_swz(*conversion_swizzle, i);

      if (new_chan == RC_SWIZZLE_UNUSED)
         continue;

      if ((1 << i) & src->Negate)
         new_negate |= 1 << new_chan;
   }
   src->Negate = new_negate;
}

/**
 * This function is the same as rc_pair_rewrite_writemask() except it
 * operates on normal instructions.
 */
void
rc_normal_rewrite_writemask(struct rc_instruction *inst, unsigned int conversion_swizzle)
{
   struct rc_sub_instruction *sub = &inst->U.I;
   const struct rc_opcode_info *info = rc_get_opcode_info(sub->Opcode);
   sub->DstReg.WriteMask = rewrite_writemask(sub->DstReg.WriteMask, conversion_swizzle);

   if (info->HasTexture) {
      unsigned int i;
      assert(sub->TexSwizzle == RC_SWIZZLE_XYZW);
      for (i = 0; i < 4; i++) {
         unsigned int swz = GET_SWZ(conversion_swizzle, i);
         if (swz > 3)
            continue;
         SET_SWZ(sub->TexSwizzle, swz, i);
      }
   }

   if (!srcs_need_rewrite(info)) {
      return;
   }

   rc_for_all_reads_src(inst, normal_rewrite_writemask_cb, &conversion_swizzle);
}

/**
 * This function replaces each value 'swz' in swizzle with the value of
 * GET_SWZ(conversion_swizzle, swz).  So, if you want to change all the X's
 * in swizzle to Y, then conversion_swizzle should be Y___ (0xff9).  If you want
 * to change all the Y's in swizzle to X, then conversion_swizzle should be
 * _X__ (0xfc7).  If you want to change the Y's to X and the X's to Y, then
 * conversion swizzle should be YX__ (0xfc1).
 * @param swizzle The swizzle to change
 * @param conversion_swizzle Describes the conversion to perform on the swizzle
 * @return A converted swizzle
 */
unsigned int
rc_rewrite_swizzle(unsigned int swizzle, unsigned int conversion_swizzle)
{
   unsigned int chan;
   unsigned int out_swizzle = swizzle;

   for (chan = 0; chan < 4; chan++) {
      unsigned int swz = GET_SWZ(swizzle, chan);
      unsigned int new_swz;
      if (swz > 3) {
         SET_SWZ(out_swizzle, chan, swz);
      } else {
         new_swz = GET_SWZ(conversion_swizzle, swz);
         if (new_swz != RC_SWIZZLE_UNUSED) {
            SET_SWZ(out_swizzle, chan, new_swz);
         } else {
            SET_SWZ(out_swizzle, chan, swz);
         }
      }
   }
   return out_swizzle;
}

/**
 * Left multiplication of a register with a swizzle
 */
struct rc_src_register
lmul_swizzle(unsigned int swizzle, struct rc_src_register srcreg)
{
   struct rc_src_register tmp = srcreg;
   int i;
   tmp.Swizzle = 0;
   tmp.Negate = 0;
   for (i = 0; i < 4; ++i) {
      rc_swizzle swz = GET_SWZ(swizzle, i);
      if (swz < 4) {
         tmp.Swizzle |= GET_SWZ(srcreg.Swizzle, swz) << (i * 3);
         tmp.Negate |= GET_BIT(srcreg.Negate, swz) << i;
      } else {
         tmp.Swizzle |= swz << (i * 3);
      }
   }
   return tmp;
}

void
reset_srcreg(struct rc_src_register *reg)
{
   memset(reg, 0, sizeof(struct rc_src_register));
   reg->Swizzle = RC_SWIZZLE_XYZW;
}

unsigned int
rc_src_reads_dst_mask(rc_register_file src_file, unsigned int src_idx, unsigned int src_swz,
                      rc_register_file dst_file, unsigned int dst_idx, unsigned int dst_mask)
{
   if (src_file != dst_file || src_idx != dst_idx) {
      return RC_MASK_NONE;
   }
   return dst_mask & rc_swizzle_to_writemask(src_swz);
}

/**
 * @return A bit mask specifying whether this swizzle will select from an RGB
 * source, an Alpha source, or both.
 */
unsigned int
rc_source_type_swz(unsigned int swizzle)
{
   unsigned int chan;
   unsigned int swz = RC_SWIZZLE_UNUSED;
   unsigned int ret = RC_SOURCE_NONE;

   for (chan = 0; chan < 4; chan++) {
      swz = GET_SWZ(swizzle, chan);
      if (swz == RC_SWIZZLE_W) {
         ret |= RC_SOURCE_ALPHA;
      } else if (swz == RC_SWIZZLE_X || swz == RC_SWIZZLE_Y || swz == RC_SWIZZLE_Z) {
         ret |= RC_SOURCE_RGB;
      }
   }
   return ret;
}

unsigned int
rc_source_type_mask(unsigned int mask)
{
   unsigned int ret = RC_SOURCE_NONE;

   if (mask & RC_MASK_XYZ)
      ret |= RC_SOURCE_RGB;

   if (mask & RC_MASK_W)
      ret |= RC_SOURCE_ALPHA;

   return ret;
}

struct src_select {
   rc_register_file File;
   int Index;
   unsigned int SrcType;
   unsigned int Swizzle;
};

struct can_use_presub_data {
   struct src_select Selects[5];
   unsigned int SelectCount;
   const struct rc_src_register *ReplaceReg;
   unsigned int ReplaceRemoved;
};

static void
can_use_presub_data_add_select(struct can_use_presub_data *data, rc_register_file file,
                               unsigned int index, unsigned int swizzle)
{
   struct src_select *select;

   select = &data->Selects[data->SelectCount++];
   select->File = file;
   select->Index = index;
   select->SrcType = rc_source_type_swz(swizzle);
   select->Swizzle = swizzle;
}

/**
 * This callback function counts the number of sources in inst that are
 * different from the sources in can_use_presub_data->RemoveSrcs.
 */
static void
can_use_presub_read_cb(void *userdata, struct rc_instruction *inst, struct rc_src_register *src)
{
   struct can_use_presub_data *d = userdata;

   if (!d->ReplaceRemoved && src == d->ReplaceReg) {
      d->ReplaceRemoved = 1;
      return;
   }

   if (src->File == RC_FILE_NONE)
      return;

   can_use_presub_data_add_select(d, src->File, src->Index, src->Swizzle);
}

unsigned int
rc_inst_can_use_presub(struct radeon_compiler *c, struct rc_instruction *inst,
                       rc_presubtract_op presub_op, unsigned int presub_writemask,
                       const struct rc_src_register *replace_reg,
                       const struct rc_src_register *presub_src0,
                       const struct rc_src_register *presub_src1)
{
   struct can_use_presub_data d;
   unsigned int num_presub_srcs;
   unsigned int i;
   const struct rc_opcode_info *info = rc_get_opcode_info(inst->U.I.Opcode);
   int rgb_count = 0, alpha_count = 0;
   unsigned int src_type0, src_type1;

   if (presub_op == RC_PRESUB_NONE) {
      return 1;
   }

   if (info->HasTexture) {
      return 0;
   }

   struct rc_src_register test_reg = *replace_reg;
   test_reg.File = RC_FILE_PRESUB;
   if (!c->SwizzleCaps->IsNative(info->Opcode, test_reg)) {
      return 0;
   }

   /* We can't allow constant swizzles from presubtract, because it is not possible
    * to rewrite it to a native swizzle later. */
   if (!c->is_r500) {
      for (i = 0; i < 4; i++) {
         rc_swizzle swz = GET_SWZ(replace_reg->Swizzle, i);
         if (swz > RC_SWIZZLE_W && swz < RC_SWIZZLE_UNUSED)
            return 0;
      }
   }

   /* We can't use more than one presubtract value in an
    * instruction, unless the two prsubtract operations
    * are the same and read from the same registers.
    * XXX For now we will limit instructions to only one presubtract
    * value.*/
   if (inst->U.I.PreSub.Opcode != RC_PRESUB_NONE) {
      return 0;
   }

   memset(&d, 0, sizeof(d));
   d.ReplaceReg = replace_reg;

   rc_for_all_reads_src(inst, can_use_presub_read_cb, &d);

   num_presub_srcs = rc_presubtract_src_reg_count(presub_op);

   src_type0 = rc_source_type_swz(presub_src0->Swizzle);
   can_use_presub_data_add_select(&d, presub_src0->File, presub_src0->Index, presub_src0->Swizzle);

   if (num_presub_srcs > 1) {
      src_type1 = rc_source_type_swz(presub_src1->Swizzle);
      can_use_presub_data_add_select(&d, presub_src1->File, presub_src1->Index,
                                     presub_src1->Swizzle);

      /* Even if both of the presub sources read from the same
       * register, we still need to use 2 different source selects
       * for them, so we need to increment the count to compensate.
       */
      if (presub_src0->File == presub_src1->File && presub_src0->Index == presub_src1->Index) {
         if (src_type0 & src_type1 & RC_SOURCE_RGB) {
            rgb_count++;
         }
         if (src_type0 & src_type1 & RC_SOURCE_ALPHA) {
            alpha_count++;
         }
      }
   }

   /* Count the number of source selects for Alpha and RGB.  If we
    * encounter two of the same source selects then we can ignore the
    * first one. */
   for (i = 0; i < d.SelectCount; i++) {
      unsigned int j;
      unsigned int src_type = d.Selects[i].SrcType;
      for (j = i + 1; j < d.SelectCount; j++) {
         /* Even if the sources are the same now, they will not be the
          * same later, if we have to rewrite some non-native swizzle. */
         if (!c->is_r500 && (!r300_swizzle_is_native_basic(d.Selects[i].Swizzle) ||
                             !r300_swizzle_is_native_basic(d.Selects[j].Swizzle)))
            continue;
         if (d.Selects[i].File == d.Selects[j].File && d.Selects[i].Index == d.Selects[j].Index) {
            src_type &= ~d.Selects[j].SrcType;
         }
      }
      if (src_type & RC_SOURCE_RGB) {
         rgb_count++;
      }

      if (src_type & RC_SOURCE_ALPHA) {
         alpha_count++;
      }
   }

   if (rgb_count > 3 || alpha_count > 3) {
      return 0;
   }

   return 1;
}

struct max_data {
   unsigned int Max;
   unsigned int HasFileType;
   rc_register_file File;
};

static void
max_callback(void *userdata, struct rc_instruction *inst, rc_register_file file, unsigned int index,
             unsigned int mask)
{
   struct max_data *d = (struct max_data *)userdata;
   if (file == d->File && (!d->HasFileType || index > d->Max)) {
      d->Max = index;
      d->HasFileType = 1;
   }
}

/**
 * @return The maximum index of the specified register file used by the
 * program.
 */
int
rc_get_max_index(struct radeon_compiler *c, rc_register_file file)
{
   struct max_data data;
   struct rc_instruction *inst;
   data.Max = 0;
   data.HasFileType = 0;
   data.File = file;
   for (inst = c->Program.Instructions.Next; inst != &c->Program.Instructions; inst = inst->Next) {
      rc_for_all_reads_mask(inst, max_callback, &data);
      rc_for_all_writes_mask(inst, max_callback, &data);
   }
   if (!data.HasFileType) {
      return -1;
   } else {
      return data.Max;
   }
}

/**
 * This function removes a source from a pair instructions.
 * @param inst
 * @param src_type RC_SOURCE_RGB, RC_SOURCE_ALPHA, or both bitwise or'd
 * @param source The index of the source to remove

 */
void
rc_pair_remove_src(struct rc_instruction *inst, unsigned int src_type, unsigned int source)
{
   if (src_type & RC_SOURCE_RGB) {
      memset(&inst->U.P.RGB.Src[source], 0, sizeof(struct rc_pair_instruction_source));
   }

   if (src_type & RC_SOURCE_ALPHA) {
      memset(&inst->U.P.Alpha.Src[source], 0, sizeof(struct rc_pair_instruction_source));
   }
}

/**
 * @return RC_OPCODE_NOOP if inst is not a flow control instruction.
 * @return The opcode of inst if it is a flow control instruction.
 */
rc_opcode
rc_get_flow_control_inst(struct rc_instruction *inst)
{
   const struct rc_opcode_info *info;
   if (inst->Type == RC_INSTRUCTION_NORMAL) {
      info = rc_get_opcode_info(inst->U.I.Opcode);
   } else {
      info = rc_get_opcode_info(inst->U.P.RGB.Opcode);
      /*A flow control instruction shouldn't have an alpha
       * instruction.*/
      assert(!info->IsFlowControl || inst->U.P.Alpha.Opcode == RC_OPCODE_NOP);
   }

   if (info->IsFlowControl)
      return info->Opcode;
   else
      return RC_OPCODE_NOP;
}

/**
 * @return The BGNLOOP instruction that starts the loop ended by endloop.
 */
struct rc_instruction *
rc_match_endloop(struct rc_instruction *endloop)
{
   unsigned int endloop_count = 0;
   struct rc_instruction *inst;
   for (inst = endloop->Prev; inst != endloop; inst = inst->Prev) {
      rc_opcode op = rc_get_flow_control_inst(inst);
      if (op == RC_OPCODE_ENDLOOP) {
         endloop_count++;
      } else if (op == RC_OPCODE_BGNLOOP) {
         if (endloop_count == 0) {
            return inst;
         } else {
            endloop_count--;
         }
      }
   }
   return NULL;
}

/**
 * @return The ENDLOOP instruction that ends the loop started by bgnloop.
 */
struct rc_instruction *
rc_match_bgnloop(struct rc_instruction *bgnloop)
{
   unsigned int bgnloop_count = 0;
   struct rc_instruction *inst;
   for (inst = bgnloop->Next; inst != bgnloop; inst = inst->Next) {
      rc_opcode op = rc_get_flow_control_inst(inst);
      if (op == RC_OPCODE_BGNLOOP) {
         bgnloop_count++;
      } else if (op == RC_OPCODE_ENDLOOP) {
         if (bgnloop_count == 0) {
            return inst;
         } else {
            bgnloop_count--;
         }
      }
   }
   return NULL;
}

/**
 * @return A conversion swizzle for converting from old_mask->new_mask
 */
unsigned int
rc_make_conversion_swizzle(unsigned int old_mask, unsigned int new_mask)
{
   unsigned int conversion_swizzle = rc_init_swizzle(RC_SWIZZLE_UNUSED, 0);
   unsigned int old_idx;
   unsigned int new_idx = 0;
   for (old_idx = 0; old_idx < 4; old_idx++) {
      if (!GET_BIT(old_mask, old_idx))
         continue;
      for (; new_idx < 4; new_idx++) {
         if (GET_BIT(new_mask, new_idx)) {
            SET_SWZ(conversion_swizzle, old_idx, new_idx);
            new_idx++;
            break;
         }
      }
   }
   return conversion_swizzle;
}

/**
 * @return 1 if the register contains an immediate value, 0 otherwise.
 */
unsigned int
rc_src_reg_is_immediate(struct radeon_compiler *c, unsigned int file, unsigned int index)
{
   return file == RC_FILE_CONSTANT &&
          c->Program.Constants.Constants[index].Type == RC_CONSTANT_IMMEDIATE;
}

/**
 * @return The immediate value in the specified register.
 */
float
rc_get_constant_value(struct radeon_compiler *c, unsigned int index, unsigned int swizzle,
                      unsigned int negate, unsigned int chan)
{
   float base = 1.0f;
   int swz = GET_SWZ(swizzle, chan);
   if (swz >= 4 || index >= c->Program.Constants.Count) {
      rc_error(c, "get_constant_value: Can't find a value");
      return 0.0f;
   }
   if (GET_BIT(negate, chan)) {
      base = -1.0f;
   }
   return base * c->Program.Constants.Constants[index].u.Immediate[swz];
}

/**
 * This function returns the component value (RC_SWIZZLE_*) of the first used
 * channel in the swizzle.  This is only useful for scalar instructions that are
 * known to use only one channel of the swizzle.
 */
unsigned int
rc_get_scalar_src_swz(unsigned int swizzle)
{
   unsigned int swz, chan;
   for (chan = 0; chan < 4; chan++) {
      swz = GET_SWZ(swizzle, chan);
      if (swz != RC_SWIZZLE_UNUSED) {
         break;
      }
   }
   assert(swz != RC_SWIZZLE_UNUSED);
   return swz;
}

bool
rc_inst_has_three_diff_temp_srcs(struct rc_instruction *inst)
{
   return (inst->U.I.SrcReg[0].File == RC_FILE_TEMPORARY &&
           inst->U.I.SrcReg[1].File == RC_FILE_TEMPORARY &&
           inst->U.I.SrcReg[2].File == RC_FILE_TEMPORARY &&
           inst->U.I.SrcReg[0].Index != inst->U.I.SrcReg[1].Index &&
           inst->U.I.SrcReg[1].Index != inst->U.I.SrcReg[2].Index &&
           inst->U.I.SrcReg[0].Index != inst->U.I.SrcReg[2].Index);
}

float
rc_inline_to_float(int index)
{
   int r300_exponent = (index >> 3) & 0xf;
   unsigned r300_mantissa = index & 0x7;
   unsigned float_exponent;
   unsigned real_float;

   r300_exponent -= 7;
   float_exponent = r300_exponent + 127;
   real_float = (r300_mantissa << 20) | (float_exponent << 23);
   return uif(real_float);
}