Free Hero Mesh

Object**objects;
Uint32 nobjects;
Value globals[0x800];
Uint32 firstobj=VOIDLINK;
Uint32 lastobj=VOIDLINK;
Uint32 playfield[64*64];
Uint8 pfwidth,pfheight;
Sint8 gameover,key_ignored;

typedef struct {
  Uint16 msg;
  Uint32 from;
  Value arg1,arg2,arg3;
} MessageVars;

static jmp_buf my_env;
static const char*my_error;
static MessageVars msgvars;
static char lastimage_processing,changed;
static Value vstack[VSTACKSIZE];
static int vstackptr;

#define Throw(x) (my_error=(x),longjmp(my_env,1))
#define StackReq(x,y) do{ if(vstackptr<(x)) Throw("Stack underflow"); if(vstackptr-(x)+(y)>=VSTACKSIZE) Throw("Stack overflow"); }while(0)
#define Push(x) (vstack[vstackptr++]=(x))
#define Pop() (vstack[--vstackptr])

    return v.u;
  } else {
    Throw("Cannot convert non-object to object");
  }
}

// Here is where the execution of a Free Hero Mesh bytecode subroutine is executed.
#define NoIgnore() do{ changed=1; }while(0)
#define GetVariableOf(a,b) (i=v_object(Pop()),i==VOIDLINK?NVALUE(0):b(objects[i]->a))
static void execute_program(Uint16*code,int ptr,Uint32 obj) {
  Uint32 i;
  Object*o=objects[obj];
  Value t1,t2;
  if(StackProtection()) Throw("Call stack overflow");
  for(;;) switch(code[ptr++]) {
    case 0x0000 ... 0x00FF: StackReq(0,1); Push(NVALUE(code[ptr-1])); break;
    case 0x0100 ... 0x01FF: StackReq(0,1); Push(NVALUE(code[ptr-1]-0x200)); break;
    case 0x0200 ... 0x02FF: StackReq(0,1); Push(MVALUE(code[ptr-1]&255)); break;
    case 0x0300 ... 0x03FF: StackReq(0,1); Push(UVALUE(code[ptr-1]&255,TY_SOUND)); break;
    case 0x0400 ... 0x04FF: StackReq(0,1); Push(UVALUE(code[ptr-1]&255,TY_USOUND)); break;
    case 0x2000 ... 0x2FFF: StackReq(0,1); Push(o->uservars[code[ptr-1]&0xFFF]); break;
    case 0x3000 ... 0x3FFF: NoIgnore(); StackReq(1,0); o->uservars[code[ptr-1]&0xFFF]=Pop(); break;
    case 0x4000 ... 0x7FFF: StackReq(0,1); Push(CVALUE(code[ptr-1]-0x4000)); break;
    case 0x87E8 ... 0x87FF: StackReq(0,1); Push(NVALUE(1UL<<(code[ptr-1]&31))); break;
    case 0xC000 ... 0xFFFF: StackReq(0,1); Push(NVALUE((code[ptr-1]&0x3FFF)+256)); break;
    case OP_CALLSUB: execute_program(code,code[ptr++],obj); break;
    case OP_CLASS: StackReq(0,1); Push(CVALUE(o->class)); break;
    case OP_CLASS_C: StackReq(1,1); Push(GetVariableOf(class,CVALUE)); break;
    case OP_DROP: StackReq(1,0); Pop(); break;
    case OP_DROP_D: StackReq(2,0); Pop(); Pop(); break;
    case OP_DUP: StackReq(1,2); t1=Pop(); Push(t1); Push(t1); break;
    case OP_GOTO: ptr=code[ptr]; break;
    case OP_IF: StackReq(1,0); if(v_bool(Pop())) ptr=code[ptr]; else ptr++; break;
    case OP_INT16: StackReq(0,1); Push(NVALUE(code[ptr++])); break;
    case OP_INT32: StackReq(0,1); t1=UVALUE(code[ptr++]<<16,TY_NUMBER); t1.u|=code[ptr++]; Push(t1); break;
    case OP_LAND: StackReq(2,1); t1=Pop(); t2=Pop(); if(v_bool(t1) && v_bool(t2)) Push(NVALUE(1)); else Push(NVALUE(0)); break;
    case OP_LNOT: StackReq(1,1); if(v_bool(Pop())) Push(NVALUE(0)); else Push(NVALUE(1)); break;
    case OP_LOR: StackReq(2,1); t1=Pop(); t2=Pop(); if(v_bool(t1) || v_bool(t2)) Push(NVALUE(1)); else Push(NVALUE(0)); break;
    case OP_LOSELEVEL: gameover=-1; Throw(0); break;
    case OP_NIP: StackReq(2,1); t1=Pop(); Pop(); Push(t1); break;
    case OP_RET: return;
    case OP_SWAP: StackReq(2,2); t1=Pop(); t2=Pop(); Push(t1); Push(t2); break;
    case OP_WINLEVEL: key_ignored=0; gameover=1; Throw(0); break;
    default: Throw("Internal error: Unrecognized opcode");
  }
}

static Value send_message(Uint32 from,Uint32 to,Uint16 msg,Value arg1,Value arg2,Value arg3) {
  MessageVars saved=msgvars;
  Uint16 c=objects[to]->class;

  for(i=0;i<64*64;i++) playfield[i]=VOIDLINK;
  firstobj=lastobj=VOIDLINK;
  if(!objects) return;
  for(i=0;i<nobjects;i++) free(objects[i]);
  nobjects=0;
  free(objects);
  objects=0;
  gameover=0;
}

const char*execute_turn(int key) {
  if(setjmp(my_env)) return my_error;
  changed=0;
  key_ignored=0;
  lastimage_processing=0;
  vstackptr=0;
  
  return 0;
}