Method _exec

output/java/1.4.15/Interpreter.java:172–487

(STWriter out, InstanceScope scope)

    }

    protected int _exec(STWriter out, InstanceScope scope) {
        final ST self = scope.st;
        int start = out.index(); // track char we're about to write
        int prevOpcode = 0;
        int n = 0; // how many char we write out
        int nargs;
        int nameIndex;
        int addr;
        String name;
        Object o, left, right;
        ST st;
        Object[] options;
        byte[] code = self.impl.instrs;        // which code block are we executing
        int ip = 0;
        while ( ip<self.impl.codeSize ) {
            if ( trace|| debug ) trace(scope, ip);
            short opcode = code[ip];
            //count[opcode]++;
            scope.ip = ip;
            ip++; //jump to next instruction or first byte of operand
            switch ( opcode ) {
                case Bytecode.INSTR_LOAD_STR:
                    // just testing... load_str(self, ip);
                    ip += Bytecode.OPND_SIZE_IN_BYTES;
                                                                                     break;
                case Bytecode.INSTR_LOAD_ATTR:
                    nameIndex = getShort(code, ip);
                    ip += Bytecode.OPND_SIZE_IN_BYTES;
                    name = self.impl.strings[nameIndex];
                    try {
                        o = getAttribute(scope, name);
                        if ( o== ST.EMPTY_ATTR ) o = null;
                        }
                    catch (STNoSuchAttributeException nsae) {
                        errMgr.runTimeError(this, scope, ErrorType.NO_SUCH_ATTRIBUTE, name);
                        o = null;
                    }
                    operands[++sp] = o;
                    break;
                case Bytecode.INSTR_LOAD_LOCAL:
                    int valueIndex = getShort(code, ip);
                    ip += Bytecode.OPND_SIZE_IN_BYTES;
                    o = self.locals[valueIndex];
                    if ( o== ST.EMPTY_ATTR ) o = null;
                    operands[++sp] = o;
                    break;
                case Bytecode.INSTR_LOAD_PROP:
                    nameIndex = getShort(code, ip);
                    ip += Bytecode.OPND_SIZE_IN_BYTES;
                    o = operands[sp--];
                    name = self.impl.strings[nameIndex];
                    operands[++sp] = getObjectProperty(out, scope, o, name);
                    break;
                case Bytecode.INSTR_LOAD_PROP_IND:
                    Object propName = operands[sp--];
                    o = operands[sp];
                    operands[sp] = getObjectProperty(out, scope, o, propName);
                    break;