/*
 * Copyright (C) 2012 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/* This file contains codegen for the X86 ISA */

#include "x86_lir.h"
#include "codegen_x86.h"
#include "../codegen_util.h"
#include "../ralloc_util.h"

namespace art {

/*
 * Perform register memory operation.
 */
LIR* X86Codegen::GenRegMemCheck(CompilationUnit* cu, ConditionCode c_code,
                                int reg1, int base, int offset, ThrowKind kind)
{
  LIR* tgt = RawLIR(cu, 0, kPseudoThrowTarget, kind,
                    cu->current_dalvik_offset, reg1, base, offset);
  OpRegMem(cu, kOpCmp, reg1, base, offset);
  LIR* branch = OpCondBranch(cu, c_code, tgt);
  // Remember branch target - will process later
  InsertGrowableList(cu, &cu->throw_launchpads, reinterpret_cast<uintptr_t>(tgt));
  return branch;
}

/*
 * Compare two 64-bit values
 *    x = y     return  0
 *    x < y     return -1
 *    x > y     return  1
 *
 *    slt   t0,  x.hi, y.hi;        # (x.hi < y.hi) ? 1:0
 *    sgt   t1,  x.hi, y.hi;        # (y.hi > x.hi) ? 1:0
 *    subu  res, t0, t1             # res = -1:1:0 for [ < > = ]
 *    bnez  res, finish
 *    sltu  t0, x.lo, y.lo
 *    sgtu  r1, x.lo, y.lo
 *    subu  res, t0, t1
 * finish:
 *
 */
void X86Codegen::GenCmpLong(CompilationUnit* cu, RegLocation rl_dest, RegLocation rl_src1,
                            RegLocation rl_src2)
{
  FlushAllRegs(cu);
  LockCallTemps(cu);  // Prepare for explicit register usage
  LoadValueDirectWideFixed(cu, rl_src1, r0, r1);
  LoadValueDirectWideFixed(cu, rl_src2, r2, r3);
  // Compute (r1:r0) = (r1:r0) - (r3:r2)
  OpRegReg(cu, kOpSub, r0, r2);  // r0 = r0 - r2
  OpRegReg(cu, kOpSbc, r1, r3);  // r1 = r1 - r3 - CF
  NewLIR2(cu, kX86Set8R, r2, kX86CondL);  // r2 = (r1:r0) < (r3:r2) ? 1 : 0
  NewLIR2(cu, kX86Movzx8RR, r2, r2);
  OpReg(cu, kOpNeg, r2);         // r2 = -r2
  OpRegReg(cu, kOpOr, r0, r1);   // r0 = high | low - sets ZF
  NewLIR2(cu, kX86Set8R, r0, kX86CondNz);  // r0 = (r1:r0) != (r3:r2) ? 1 : 0
  NewLIR2(cu, kX86Movzx8RR, r0, r0);
  OpRegReg(cu, kOpOr, r0, r2);   // r0 = r0 | r2
  RegLocation rl_result = LocCReturn();
  StoreValue(cu, rl_dest, rl_result);
}

X86ConditionCode X86ConditionEncoding(ConditionCode cond) {
  switch (cond) {
    case kCondEq: return kX86CondEq;
    case kCondNe: return kX86CondNe;
    case kCondCs: return kX86CondC;
    case kCondCc: return kX86CondNc;
    case kCondMi: return kX86CondS;
    case kCondPl: return kX86CondNs;
    case kCondVs: return kX86CondO;
    case kCondVc: return kX86CondNo;
    case kCondHi: return kX86CondA;
    case kCondLs: return kX86CondBe;
    case kCondGe: return kX86CondGe;
    case kCondLt: return kX86CondL;
    case kCondGt: return kX86CondG;
    case kCondLe: return kX86CondLe;
    case kCondAl:
    case kCondNv: LOG(FATAL) << "Should not reach here";
  }
  return kX86CondO;
}

LIR* X86Codegen::OpCmpBranch(CompilationUnit* cu, ConditionCode cond, int src1, int src2,
                             LIR* target)
{
  NewLIR2(cu, kX86Cmp32RR, src1, src2);
  X86ConditionCode cc = X86ConditionEncoding(cond);
  LIR* branch = NewLIR2(cu, kX86Jcc8, 0 /* lir operand for Jcc offset */ ,
                        cc);
  branch->target = target;
  return branch;
}

LIR* X86Codegen::OpCmpImmBranch(CompilationUnit* cu, ConditionCode cond, int reg,
                                int check_value, LIR* target)
{
  if ((check_value == 0) && (cond == kCondEq || cond == kCondNe)) {
    // TODO: when check_value == 0 and reg is rCX, use the jcxz/nz opcode
    NewLIR2(cu, kX86Test32RR, reg, reg);
  } else {
    NewLIR2(cu, IS_SIMM8(check_value) ? kX86Cmp32RI8 : kX86Cmp32RI, reg, check_value);
  }
  X86ConditionCode cc = X86ConditionEncoding(cond);
  LIR* branch = NewLIR2(cu, kX86Jcc8, 0 /* lir operand for Jcc offset */ , cc);
  branch->target = target;
  return branch;
}

LIR* X86Codegen::OpRegCopyNoInsert(CompilationUnit *cu, int r_dest, int r_src)
{
  if (X86_FPREG(r_dest) || X86_FPREG(r_src))
    return OpFpRegCopy(cu, r_dest, r_src);
  LIR* res = RawLIR(cu, cu->current_dalvik_offset, kX86Mov32RR,
                    r_dest, r_src);
  if (r_dest == r_src) {
    res->flags.is_nop = true;
  }
  return res;
}

LIR* X86Codegen::OpRegCopy(CompilationUnit *cu, int r_dest, int r_src)
{
  LIR *res = OpRegCopyNoInsert(cu, r_dest, r_src);
  AppendLIR(cu, res);
  return res;
}

void X86Codegen::OpRegCopyWide(CompilationUnit *cu, int dest_lo, int dest_hi,
                               int src_lo, int src_hi)
{
  bool dest_fp = X86_FPREG(dest_lo) && X86_FPREG(dest_hi);
  bool src_fp = X86_FPREG(src_lo) && X86_FPREG(src_hi);
  assert(X86_FPREG(src_lo) == X86_FPREG(src_hi));
  assert(X86_FPREG(dest_lo) == X86_FPREG(dest_hi));
  if (dest_fp) {
    if (src_fp) {
      OpRegCopy(cu, S2d(dest_lo, dest_hi), S2d(src_lo, src_hi));
    } else {
      // TODO: Prevent this from happening in the code. The result is often
      // unused or could have been loaded more easily from memory.
      NewLIR2(cu, kX86MovdxrRR, dest_lo, src_lo);
      NewLIR2(cu, kX86MovdxrRR, dest_hi, src_hi);
      NewLIR2(cu, kX86PsllqRI, dest_hi, 32);
      NewLIR2(cu, kX86OrpsRR, dest_lo, dest_hi);
    }
  } else {
    if (src_fp) {
      NewLIR2(cu, kX86MovdrxRR, dest_lo, src_lo);
      NewLIR2(cu, kX86PsrlqRI, src_lo, 32);
      NewLIR2(cu, kX86MovdrxRR, dest_hi, src_lo);
    } else {
      // Handle overlap
      if (src_hi == dest_lo) {
        OpRegCopy(cu, dest_hi, src_hi);
        OpRegCopy(cu, dest_lo, src_lo);
      } else {
        OpRegCopy(cu, dest_lo, src_lo);
        OpRegCopy(cu, dest_hi, src_hi);
      }
    }
  }
}

void X86Codegen::GenFusedLongCmpBranch(CompilationUnit* cu, BasicBlock* bb, MIR* mir) {
  LIR* label_list = cu->block_label_list;
  LIR* taken = &label_list[bb->taken->id];
  RegLocation rl_src1 = GetSrcWide(cu, mir, 0);
  RegLocation rl_src2 = GetSrcWide(cu, mir, 2);
  FlushAllRegs(cu);
  LockCallTemps(cu);  // Prepare for explicit register usage
  LoadValueDirectWideFixed(cu, rl_src1, r0, r1);
  LoadValueDirectWideFixed(cu, rl_src2, r2, r3);
  ConditionCode ccode = static_cast<ConditionCode>(mir->dalvikInsn.arg[0]);
  // Swap operands and condition code to prevent use of zero flag.
  if (ccode == kCondLe || ccode == kCondGt) {
    // Compute (r3:r2) = (r3:r2) - (r1:r0)
    OpRegReg(cu, kOpSub, r2, r0);  // r2 = r2 - r0
    OpRegReg(cu, kOpSbc, r3, r1);  // r3 = r3 - r1 - CF
  } else {
    // Compute (r1:r0) = (r1:r0) - (r3:r2)
    OpRegReg(cu, kOpSub, r0, r2);  // r0 = r0 - r2
    OpRegReg(cu, kOpSbc, r1, r3);  // r1 = r1 - r3 - CF
  }
  switch (ccode) {
    case kCondEq:
    case kCondNe:
      OpRegReg(cu, kOpOr, r0, r1);  // r0 = r0 | r1
      break;
    case kCondLe:
      ccode = kCondGe;
      break;
    case kCondGt:
      ccode = kCondLt;
      break;
    case kCondLt:
    case kCondGe:
      break;
    default:
      LOG(FATAL) << "Unexpected ccode: " << ccode;
  }
  OpCondBranch(cu, ccode, taken);
}

RegLocation X86Codegen::GenDivRemLit(CompilationUnit* cu, RegLocation rl_dest, int reg_lo,
                                     int lit, bool is_div)
{
  LOG(FATAL) << "Unexpected use of GenDivRemLit for x86";
  return rl_dest;
}

RegLocation X86Codegen::GenDivRem(CompilationUnit* cu, RegLocation rl_dest, int reg_lo,
                                  int reg_hi, bool is_div)
{
  LOG(FATAL) << "Unexpected use of GenDivRem for x86";
  return rl_dest;
}

bool X86Codegen::GenInlinedMinMaxInt(CompilationUnit *cu, CallInfo* info, bool is_min)
{
  DCHECK_EQ(cu->instruction_set, kX86);
  RegLocation rl_src1 = info->args[0];
  RegLocation rl_src2 = info->args[1];
  rl_src1 = LoadValue(cu, rl_src1, kCoreReg);
  rl_src2 = LoadValue(cu, rl_src2, kCoreReg);
  RegLocation rl_dest = InlineTarget(cu, info);
  RegLocation rl_result = EvalLoc(cu, rl_dest, kCoreReg, true);
  OpRegReg(cu, kOpCmp, rl_src1.low_reg, rl_src2.low_reg);
  DCHECK_EQ(cu->instruction_set, kX86);
  LIR* branch = NewLIR2(cu, kX86Jcc8, 0, is_min ? kX86CondG : kX86CondL);
  OpRegReg(cu, kOpMov, rl_result.low_reg, rl_src1.low_reg);
  LIR* branch2 = NewLIR1(cu, kX86Jmp8, 0);
  branch->target = NewLIR0(cu, kPseudoTargetLabel);
  OpRegReg(cu, kOpMov, rl_result.low_reg, rl_src2.low_reg);
  branch2->target = NewLIR0(cu, kPseudoTargetLabel);
  StoreValue(cu, rl_dest, rl_result);
  return true;
}

void X86Codegen::OpLea(CompilationUnit* cu, int rBase, int reg1, int reg2, int scale, int offset)
{
  NewLIR5(cu, kX86Lea32RA, rBase, reg1, reg2, scale, offset);
}

void X86Codegen::OpTlsCmp(CompilationUnit* cu, int offset, int val)
{
  NewLIR2(cu, kX86Cmp16TI8, offset, val);
}

bool X86Codegen::GenInlinedCas32(CompilationUnit* cu, CallInfo* info, bool need_write_barrier) {
  DCHECK_NE(cu->instruction_set, kThumb2);
  return false;
}

LIR* X86Codegen::OpPcRelLoad(CompilationUnit* cu, int reg, LIR* target) {
  LOG(FATAL) << "Unexpected use of OpPcRelLoad for x86";
  return NULL;
}

LIR* X86Codegen::OpVldm(CompilationUnit* cu, int rBase, int count)
{
  LOG(FATAL) << "Unexpected use of OpVldm for x86";
  return NULL;
}

LIR* X86Codegen::OpVstm(CompilationUnit* cu, int rBase, int count)
{
  LOG(FATAL) << "Unexpected use of OpVstm for x86";
  return NULL;
}

void X86Codegen::GenMultiplyByTwoBitMultiplier(CompilationUnit* cu, RegLocation rl_src,
                                               RegLocation rl_result, int lit,
                                               int first_bit, int second_bit)
{
  int t_reg = AllocTemp(cu);
  OpRegRegImm(cu, kOpLsl, t_reg, rl_src.low_reg, second_bit - first_bit);
  OpRegRegReg(cu, kOpAdd, rl_result.low_reg, rl_src.low_reg, t_reg);
  FreeTemp(cu, t_reg);
  if (first_bit != 0) {
    OpRegRegImm(cu, kOpLsl, rl_result.low_reg, rl_result.low_reg, first_bit);
  }
}

void X86Codegen::GenDivZeroCheck(CompilationUnit* cu, int reg_lo, int reg_hi)
{
  int t_reg = AllocTemp(cu);
  OpRegRegReg(cu, kOpOr, t_reg, reg_lo, reg_hi);
  GenImmedCheck(cu, kCondEq, t_reg, 0, kThrowDivZero);
  FreeTemp(cu, t_reg);
}

// Test suspend flag, return target of taken suspend branch
LIR* X86Codegen::OpTestSuspend(CompilationUnit* cu, LIR* target)
{
  OpTlsCmp(cu, Thread::ThreadFlagsOffset().Int32Value(), 0);
  return OpCondBranch(cu, (target == NULL) ? kCondNe : kCondEq, target);
}

// Decrement register and branch on condition
LIR* X86Codegen::OpDecAndBranch(CompilationUnit* cu, ConditionCode c_code, int reg, LIR* target)
{
  OpRegImm(cu, kOpSub, reg, 1);
  return OpCmpImmBranch(cu, c_code, reg, 0, target);
}

bool X86Codegen::SmallLiteralDivide(CompilationUnit* cu, Instruction::Code dalvik_opcode,
                                    RegLocation rl_src, RegLocation rl_dest, int lit)
{
  LOG(FATAL) << "Unexpected use of smallLiteralDive in x86";
  return false;
}

LIR* X86Codegen::OpIT(CompilationUnit* cu, ConditionCode cond, const char* guide)
{
  LOG(FATAL) << "Unexpected use of OpIT in x86";
  return NULL;
}
bool X86Codegen::GenAddLong(CompilationUnit* cu, RegLocation rl_dest, RegLocation rl_src1,
                         RegLocation rl_src2)
{
  FlushAllRegs(cu);
  LockCallTemps(cu);  // Prepare for explicit register usage
  LoadValueDirectWideFixed(cu, rl_src1, r0, r1);
  LoadValueDirectWideFixed(cu, rl_src2, r2, r3);
  // Compute (r1:r0) = (r1:r0) + (r2:r3)
  OpRegReg(cu, kOpAdd, r0, r2);  // r0 = r0 + r2
  OpRegReg(cu, kOpAdc, r1, r3);  // r1 = r1 + r3 + CF
  RegLocation rl_result = {kLocPhysReg, 1, 0, 0, 0, 0, 0, 0, 1, r0, r1,
                          INVALID_SREG, INVALID_SREG};
  StoreValueWide(cu, rl_dest, rl_result);
  return false;
}

bool X86Codegen::GenSubLong(CompilationUnit* cu, RegLocation rl_dest, RegLocation rl_src1,
                            RegLocation rl_src2)
{
  FlushAllRegs(cu);
  LockCallTemps(cu);  // Prepare for explicit register usage
  LoadValueDirectWideFixed(cu, rl_src1, r0, r1);
  LoadValueDirectWideFixed(cu, rl_src2, r2, r3);
  // Compute (r1:r0) = (r1:r0) + (r2:r3)
  OpRegReg(cu, kOpSub, r0, r2);  // r0 = r0 - r2
  OpRegReg(cu, kOpSbc, r1, r3);  // r1 = r1 - r3 - CF
  RegLocation rl_result = {kLocPhysReg, 1, 0, 0, 0, 0, 0, 0, 1, r0, r1,
                          INVALID_SREG, INVALID_SREG};
  StoreValueWide(cu, rl_dest, rl_result);
  return false;
}

bool X86Codegen::GenAndLong(CompilationUnit* cu, RegLocation rl_dest, RegLocation rl_src1,
                            RegLocation rl_src2)
{
  FlushAllRegs(cu);
  LockCallTemps(cu);  // Prepare for explicit register usage
  LoadValueDirectWideFixed(cu, rl_src1, r0, r1);
  LoadValueDirectWideFixed(cu, rl_src2, r2, r3);
  // Compute (r1:r0) = (r1:r0) + (r2:r3)
  OpRegReg(cu, kOpAnd, r0, r2);  // r0 = r0 - r2
  OpRegReg(cu, kOpAnd, r1, r3);  // r1 = r1 - r3 - CF
  RegLocation rl_result = {kLocPhysReg, 1, 0, 0, 0, 0, 0, 0, 1, r0, r1,
                          INVALID_SREG, INVALID_SREG};
  StoreValueWide(cu, rl_dest, rl_result);
  return false;
}

bool X86Codegen::GenOrLong(CompilationUnit* cu, RegLocation rl_dest,
                           RegLocation rl_src1, RegLocation rl_src2)
{
  FlushAllRegs(cu);
  LockCallTemps(cu);  // Prepare for explicit register usage
  LoadValueDirectWideFixed(cu, rl_src1, r0, r1);
  LoadValueDirectWideFixed(cu, rl_src2, r2, r3);
  // Compute (r1:r0) = (r1:r0) + (r2:r3)
  OpRegReg(cu, kOpOr, r0, r2);  // r0 = r0 - r2
  OpRegReg(cu, kOpOr, r1, r3);  // r1 = r1 - r3 - CF
  RegLocation rl_result = {kLocPhysReg, 1, 0, 0, 0, 0, 0, 0, 1, r0, r1,
                          INVALID_SREG, INVALID_SREG};
  StoreValueWide(cu, rl_dest, rl_result);
  return false;
}

bool X86Codegen::GenXorLong(CompilationUnit* cu, RegLocation rl_dest,
                            RegLocation rl_src1, RegLocation rl_src2)
{
  FlushAllRegs(cu);
  LockCallTemps(cu);  // Prepare for explicit register usage
  LoadValueDirectWideFixed(cu, rl_src1, r0, r1);
  LoadValueDirectWideFixed(cu, rl_src2, r2, r3);
  // Compute (r1:r0) = (r1:r0) + (r2:r3)
  OpRegReg(cu, kOpXor, r0, r2);  // r0 = r0 - r2
  OpRegReg(cu, kOpXor, r1, r3);  // r1 = r1 - r3 - CF
  RegLocation rl_result = {kLocPhysReg, 1, 0, 0, 0, 0, 0, 0, 1, r0, r1,
                          INVALID_SREG, INVALID_SREG};
  StoreValueWide(cu, rl_dest, rl_result);
  return false;
}

bool X86Codegen::GenNegLong(CompilationUnit* cu, RegLocation rl_dest, RegLocation rl_src)
{
  FlushAllRegs(cu);
  LockCallTemps(cu);  // Prepare for explicit register usage
  LoadValueDirectWideFixed(cu, rl_src, r0, r1);
  // Compute (r1:r0) = -(r1:r0)
  OpRegReg(cu, kOpNeg, r0, r0);  // r0 = -r0
  OpRegImm(cu, kOpAdc, r1, 0);   // r1 = r1 + CF
  OpRegReg(cu, kOpNeg, r1, r1);  // r1 = -r1
  RegLocation rl_result = {kLocPhysReg, 1, 0, 0, 0, 0, 0, 0, 1, r0, r1,
                          INVALID_SREG, INVALID_SREG};
  StoreValueWide(cu, rl_dest, rl_result);
  return false;
}

void X86Codegen::OpRegThreadMem(CompilationUnit* cu, OpKind op, int r_dest, int thread_offset) {
  X86OpCode opcode = kX86Bkpt;
  switch (op) {
  case kOpCmp: opcode = kX86Cmp32RT;  break;
  default:
    LOG(FATAL) << "Bad opcode: " << op;
    break;
  }
  NewLIR2(cu, opcode, r_dest, thread_offset);
}

}  // namespace art