/*

 * Copyright (c) 2002, 2006, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 *  

 */

#include <stdio.h>

#include <string.h>

static const int R_O0_num = 1000;

static const int R_I0_num = 2000;

static const int R_F0_num = 3000;

static const int R_F1_num = R_F0_num + 1;

static const int R_F2_num = R_F0_num + 2;

static const int STACK_num= 4000;

static bool LP64 = false;

static bool LONGS_IN_ONE_ENTRY = false;

static const int Op_RegI = 'I';

static const int Op_RegP = 'P';

static const int Op_RegF = 'F';

static const int Op_RegD = 'D';

static const int Op_RegL = 'L';

static const int SPARC_ARGS_IN_REGS_NUM=6;

static void print_reg( int reg ) {

  if( reg == 0 )

    printf("__");               // halve's

  else if( reg >= STACK_num && reg < STACK_num+100 )

    printf("S%d_",reg - STACK_num);

  else if( reg >= R_F0_num && reg < R_F0_num+100 )

    printf("F%d_",reg - R_F0_num);

  else if( reg >= R_O0_num && reg < R_O0_num+100 ) {

    if( LONGS_IN_ONE_ENTRY ) {

      reg -= R_O0_num;

      printf("O%d",reg>>1);

      printf(reg&1 ? "H" : "L");

    } else

      printf("O%d_",reg - R_O0_num);

  } else

    printf("Wretched: %d\n", reg);

}

static void print_convention( int *sig, const char *s, int length ) {

  // Print it out

  for( int i = 0; i < length; i++) {

    if( sig[i] == 0 ) continue; // do not print 'halves'

    print_reg( sig[i] & 0xFFFF );

    int reg = sig[i] >> 16;

    if( reg ) {

      printf(":");

      print_reg( reg );

    } else {

      printf("    ");

    }

    printf("  ");

  }

  printf("\n");

}

static int INT_SCALE( int x ) {

  return LONGS_IN_ONE_ENTRY ? (x<<1) : x;

}

static void java_convention( int *sig, const char *s, int length ) {

  if( LP64 && !LONGS_IN_ONE_ENTRY ) {

    printf("LP64 and 2-reg longs not supported\n");

    return;

  }

  for( int i = 0; i < length; i++ )

    sig[i] = s[i];              // Reset sig array

  bool is_outgoing = true;

  int int_base = (is_outgoing ? R_O0_num : R_I0_num);

  // Convention is to pack the first 6 int/oop args into the first 6

  // registers (I0-I5), extras spill to the stack.  Then pack the first

  // 32 float args into F0-F31, extras spill to the stack.  Then pad

  // all register sets to align.  Then put longs and doubles into the

  // same registers as they fit, else spill to the stack.

  int int_reg_max = SPARC_ARGS_IN_REGS_NUM;

  int flt_reg_max = 32;

  // Count int/oop and float args.  See how many stack slots we'll need

  // and where the longs & doubles will go.

  int int_reg_cnt   = 0;

  int flt_reg_cnt   = 0;

  int stk_reg_pairs = 0;

  for( int i = 0; i < length; i++) {

    switch( sig[i] ) {

    case Op_RegL:               // Longs-in-1-reg compete with int args

      if( LONGS_IN_ONE_ENTRY ) { 

        if( int_reg_cnt < int_reg_max ) int_reg_cnt++;

      }

      break;

    case Op_RegP:

      if( int_reg_cnt < int_reg_max ) int_reg_cnt++;

      else if( !LP64 )                stk_reg_pairs++;

      break;

    case Op_RegI:

      if( int_reg_cnt < int_reg_max ) int_reg_cnt++;

      else                            stk_reg_pairs++;

      break;

    case Op_RegF:

      if( flt_reg_cnt < flt_reg_max ) flt_reg_cnt++;

      else                            stk_reg_pairs++;

      break;

    }

  }

  // This is where the longs/doubles start on the stack.

  stk_reg_pairs = (stk_reg_pairs+1) & ~1; // Round

  int int_reg_pairs = (int_reg_cnt+1) & ~1; // 32-bit 2-reg longs only

  int flt_reg_pairs = (flt_reg_cnt+1) & ~1;

  int stk_reg = 0;

  int int_reg = 0;

  int flt_reg = 0;

  // Now do the signature layout

  for( int i = 0; i < length; i++) {

    int tmp = sig[i];

    if( tmp == Op_RegP )

      tmp = LP64 ? Op_RegL : Op_RegI;   // Treat ptrs and ints or long accordingly

    switch( tmp ) {

    case Op_RegI:

//  case Op_RegP: 

      if( int_reg < int_reg_max) tmp = INT_SCALE(int_reg++) + int_base;

      else                       tmp = STACK_num + stk_reg++;

      sig[i] = tmp;

      break;

    case Op_RegL: 

      if( sig[i] != Op_RegP && sig[i+1] != 'h' ) { printf("expecting (h)alf, found %c\n", sig[i+1]); return; }

//  case Op_RegP: 

      if( LONGS_IN_ONE_ENTRY ) {

        if( int_reg < int_reg_max ) {

          tmp = INT_SCALE(int_reg++) + int_base;

        } else {

          tmp = STACK_num + stk_reg_pairs;

          stk_reg_pairs += 2;

        }

      } else {

        if( int_reg_pairs < int_reg_max ) {

          tmp = int_reg_pairs + int_base;

          int_reg_pairs += 2;

        } else {

          tmp = STACK_num + stk_reg_pairs;

          stk_reg_pairs += 2;

        }

      }

      sig[i] = tmp | (tmp+1)<<16; // Smear to pair

      break;

    case Op_RegF: 

      sig[i] = (flt_reg < flt_reg_max) ? (R_F0_num + flt_reg++) : STACK_num + stk_reg++;

      break;

    case Op_RegD: 

      if( sig[i+1] != 'h' ) { printf("expecting (h)alf, found %c\n", sig[i+1]); return; }

      if( flt_reg_pairs < flt_reg_max ) {

        tmp = R_F0_num + flt_reg_pairs;

        flt_reg_pairs += 2;

      } else {

        tmp = STACK_num + stk_reg_pairs;

        stk_reg_pairs += 2;

      }

      sig[i] = tmp | (tmp+1)<<16; // Smear to pair

      break;

    case 'h': sig[i] = 0; break;

    default:

      printf("Bad character: %c\n", sig[i] );

      return;

    }

  }

  printf("java ");

  printf(LP64 ? "LP64 " : "LP32 ");

  printf(LONGS_IN_ONE_ENTRY ? "long1: " : "long2: ");

  print_convention(sig,s,length);

}

static int int_stk_helper( int i ) {

  if( i < 6 ) return R_O0_num + (LONGS_IN_ONE_ENTRY ? i<<1 : i);

  else        return STACK_num + (LP64              ? i<<1 : i);

}

static void native_convention( int *sig, const char *s, int length ) {

  if( LP64 && !LONGS_IN_ONE_ENTRY ) {

    printf("LP64 and 2-reg longs not supported\n");

    return;

  }

  for( int i = 0; i < length; i++ )

    sig[i] = s[i];              // Reset sig array

  // The native convention is V8 if !LP64, which means the V8 convention is

  // used both with and without LONGS_IN_ONE_ENTRY, an unfortunate split.  The

  // same actual machine registers are used, but they are named differently in

  // the LONGS_IN_ONE_ENTRY mode.  The LP64 convention is the V9 convention

  // which is slightly more sane.

  if( LP64 ) {

    // V9 convention: All things "as-if" on double-wide stack slots.

    // Hoist any int/ptr/long's in the first 6 to int regs.

    // Hoist any flt/dbl's in the first 16 dbl regs.

    int j = 0;                  // Count of actual args, not HALVES

    for( int i=0; i<length; i++, j++ ) {

      int tmp;

      switch( sig[i] ) {

      case Op_RegI:

        sig[i] = int_stk_helper( j );

        break;

      case Op_RegL:

        if( sig[i+1] != 'h' ) { printf("expecting (h)alf, found %c\n", sig[i+1]); return; }

      case Op_RegP:

        tmp = int_stk_helper( j );

        sig[i] = tmp | ((tmp+1) << 16); // Smear to pair

        break;

      case Op_RegF:                 // V9ism: floats go in ODD registers

        sig[i] = ((j < 16) ? R_F1_num : (STACK_num + 1)) + (j<<1);

        break;

      case Op_RegD:                 // V9ism: doubles go in EVEN/ODD regs

        tmp    = ((j < 16) ? R_F0_num : STACK_num) + (j<<1);

        sig[i] = tmp | ((tmp+1) << 16); // Smear to pair

        break;

      case 'h': sig[i] = 0; j--; break; // Do not count HALVES

      default:

        printf("Bad character: %c\n", sig[i] );

        return;

      }

    }

  } else {

    // V8 convention: first 6 things in O-regs, rest on stack.

    // Alignment is willy-nilly.

    for( int i=0; i<length; i++ ) {

      int tmp;

      switch( sig[i] ) {

      case Op_RegI:

      case Op_RegP:

      case Op_RegF:

        sig[i] = int_stk_helper( i );

        break;

      case Op_RegL:

      case Op_RegD:

        if( sig[i+1] != 'h' ) { printf("expecting (h)alf, found %c\n", sig[i+1]); return; }

        tmp = int_stk_helper( i );

        sig[i] = tmp | (int_stk_helper( i+1 ) << 16);

        break;

      case 'h': sig[i] = 0; break;

      default:

        printf("Bad character: %c\n", sig[i] );

        return;

      }

    }

  }

  printf("natv ");

  printf(LP64 ? "LP64 " : "LP32 ");

  printf(LONGS_IN_ONE_ENTRY ? "long1: " : "long2: ");

  print_convention(sig,s,length);

}

int main( int argc, char **argv ) {

  if( argc != 2 ) {

    printf("Usage: args IPFLhDh... (Java argument string)\n");

    printf("Returns argument layout\n");

    return -1;

  }

  const char *s = argv[1];

  int length = strlen(s);

  int sig[1000];

  LP64 = false; LONGS_IN_ONE_ENTRY = false;

  java_convention( sig, s, length );

  LP64 = false; LONGS_IN_ONE_ENTRY = true;

  java_convention( sig, s, length );

  LP64 = true ; LONGS_IN_ONE_ENTRY = true;

  java_convention( sig, s, length );

  LP64 = false; LONGS_IN_ONE_ENTRY = false;

  native_convention( sig, s, length );

  LP64 = false; LONGS_IN_ONE_ENTRY = true;

  native_convention( sig, s, length );

  LP64 = true ; LONGS_IN_ONE_ENTRY = true;

  native_convention( sig, s, length );

}