fixed a bug where the Opcode jump table was written to out of bounds

[cyclone68000.git] / Cyclone / OpAny.cpp

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// This file is part of the Cyclone 68000 Emulator\r
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// Copyright (c) 2011 FinalDave (emudave (at) gmail.com)\r
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// This code is licensed under the GNU General Public License version 2.0 and the MAME License.\r
// You can choose the license that has the most advantages for you.\r
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// SVN repository can be found at http://code.google.com/p/cyclone68000/\r
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#include "app.h"\r
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static unsigned char OpData[16]={0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};\r
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static unsigned short CPU_CALL OpRead16(unsigned int a)\r
{\r
  return (unsigned short)( (OpData[a&15]<<8) | OpData[(a+1)&15] );\r
}\r
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// For opcode 'op' use handler 'use'\r
void OpUse(int op,int use)\r
{\r
  char text[64]="";\r
  \r
  if (op>=0)\r
	  CyJump[op]=use;\r
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  if (op!=use) return;\r
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  // Disassemble opcode\r
  DisaPc=0;\r
  DisaText=text;\r
  DisaWord=OpRead16;\r
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  DisaGet();\r
  ot(";@ ---------- [%.4x] %s uses Op%.4x ----------\n",op,text,use);\r
}\r
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void OpFirst()\r
{\r
  ot("  ldrh r8,[r4],#2 ;@ Fetch first opcode\n");\r
  ot("  ldr pc,[r6,r8,asl #2] ;@ Jump to opcode handler\n");\r
}\r
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void OpStart(int op)\r
{\r
  Cycles=0;\r
  OpUse(op,op); // This opcode obviously uses this handler\r
  ot("Op%.4x%s\n", op, ms?"":":");\r
}\r
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void OpEnd()\r
{\r
  ot("  ldrh r8,[r4],#2 ;@ Fetch next opcode\n");\r
  ot("  subs r5,r5,#%d ;@ Subtract cycles\n",Cycles);\r
  ot("  ldrge pc,[r6,r8,asl #2] ;@ Jump to opcode handler\n");\r
  ot("  b CycloneEnd\n");\r
  ltorg();\r
  ot("\n");\r
}\r
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int OpBase(int op)\r
{\r
  int ea=op&0x3f; // Get Effective Address\r
  if (ea<0x10) return op&~0xf; // Use 1 handler for d0-d7 and a0-a7\r
  if (ea>=0x18 && ea<0x28 && (ea&7)==7) return op; // Specific handler for (a7)+ and -(a7)\r
  if (ea<0x38) return op&~7;   // Use 1 handler for (a0)-(a7), etc...\r
  return op;\r
}\r
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// Get flags, trashes r2\r
int OpGetFlags(int subtract,int xbit)\r
{\r
  ot("  mrs r9,cpsr ;@ r9=flags\n");\r
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  if (subtract) ot("  eor r9,r9,#0x20000000 ;@ Invert carry\n");\r
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  if (Accu&1) if (xbit)\r
  {\r
    ot("  mov r2,r9,lsr #28\n");\r
    ot("  strb r2,[r7,#0x45] ;@ Save X bit\n");\r
  }\r
  return 0;\r
}\r
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// -----------------------------------------------------------------\r
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void OpAny(int op)\r
{\r
  memset(OpData,0x33,sizeof(OpData));\r
  OpData[0]=(unsigned char)(op>>8);\r
  OpData[1]=(unsigned char)op;\r
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  if ((op&0xf100)==0x0000) OpArith(op);\r
  if ((op&0xc000)==0x0000) OpMove(op);\r
  if ((op&0xf5bf)==0x003c) OpArithSr(op); // Ori/Andi/Eori $nnnn,sr\r
  if ((op&0xf100)==0x0100) OpBtstReg(op);\r
  if ((op&0xff00)==0x0800) OpBtstImm(op);\r
  if ((op&0xf900)==0x4000) OpNeg(op);\r
  if ((op&0xf1c0)==0x41c0) OpLea(op);\r
  if ((op&0xf9c0)==0x40c0) OpMoveSr(op);\r
  if ((op&0xfff8)==0x4840) OpSwap(op);\r
  if ((op&0xffc0)==0x4840) OpPea(op);\r
  if ((op&0xffb8)==0x4880) OpExt(op);\r
  if ((op&0xfb80)==0x4880) OpMovem(op);\r
  if ((op&0xff00)==0x4a00) OpTst(op);\r
  if ((op&0xfff0)==0x4e40) OpTrap(op);\r
  if ((op&0xfff8)==0x4e50) OpLink(op);\r
  if ((op&0xfff8)==0x4e58) OpUnlk(op);\r
  if ((op&0xfff0)==0x4e60) OpMoveUsp(op);\r
  if ((op&0xfff8)==0x4e70) Op4E70(op); // Reset/Rts etc\r
  if ((op&0xff80)==0x4e80) OpJsr(op);\r
  if ((op&0xf000)==0x5000) OpAddq(op);\r
  if ((op&0xf0c0)==0x50c0) OpSet(op);\r
  if ((op&0xf0f8)==0x50c8) OpDbra(op);\r
  if ((op&0xf000)==0x6000) OpBranch(op);\r
  if ((op&0xf100)==0x7000) OpMoveq(op);\r
  if ((op&0xa000)==0x8000) OpArithReg(op); // Or/Sub/And/Add\r
  if ((op&0xb1f0)==0x8100) OpAbcd(op);\r
  if ((op&0xb0c0)==0x80c0) OpMul(op);\r
  if ((op&0x90c0)==0x90c0) OpAritha(op);\r
  if ((op&0xb138)==0x9100) OpAddx(op);\r
  if ((op&0xf000)==0xb000) OpCmpEor(op);\r
  if ((op&0xf130)==0xc100) OpExg(op);\r
  if ((op&0xf000)==0xe000) OpAsr(op); // Asr/l/Ror/l etc\r
  if ((op&0xf8c0)==0xe0c0) OpAsrEa(op);\r
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}\r