protected short op_call() {
int nlocals;
int i;
short thislocal;
if (operands[0] == 0) {
/* calls to zero return false */
/*
* Can't just return false because call is not treated as a store in
* execute_instruction
*/
zm.set_variable(storevar, ZFALSE);
} else {
zm.zstack.push(new ZFrameBound(isstore()));
zm.zstack.push(new Integer(storevar));
zm.zstack.push(new Integer(zm.pc));
zm.zstack.push(zm.locals);
// System.err.print("From ");
// System.err.print(Integer.toString(zm.pc, 16));
zm.pc = zm.routine_address(operands[0]);
// System.err.print(" calling routine at ");
// System.err.println(Integer.toString(zm.pc, 16));
nlocals = zm.get_code_byte();
zm.locals = new short[nlocals];
for (i = 0; i < nlocals; i++) {
thislocal = (short) (((zm.get_code_byte() << 8) & 0xFF00) | (zm.get_code_byte() & 0xFF));
if (i < (count - 1)) {
zm.locals[i] = operands[i + 1];
} else {
zm.locals[i] = thislocal;
}
}
}
return ZFALSE;
}
protected void decode_second_half() {
if (isstore()) storevar = zm.get_code_byte();
if (isbranch()) {
branchoffset = zm.get_code_byte();
branchtype = (branchoffset & 0x80) != 0;
if ((branchoffset & 0x40) != 0) /* positive 6-bit number */ branchoffset &= 0x3F;
else if ((branchoffset & 0x20) != 0) /* negative 14-bit number */
branchoffset =
(short) (0xC000 | ((branchoffset << 8) | (((short) zm.get_code_byte()) & 0xFF)));
else
/* positive 14-bit number */
branchoffset =
(short) (((branchoffset & 0x3F) << 8) | (((short) zm.get_code_byte()) & 0xFF));
}
}
protected void decode_first_half() {
int opcode;
int optype, optypes;
int optypes2 = 0; /* It takes a kludge to handle a kludge */
int optypebytes;
int isextended = 0;
opcode = zm.get_code_byte() & 0xFF;
if (opcode == OP_EXTENDED) {
isextended = 0xC0;
}
switch (isextended | opcode & 0xC0) {
case 0xC0: /* variable form */
if (isextended != 0xC0) {
opnum = opcode;
} else {
opnum = (0x100 | (zm.get_code_byte() & 0xFF));
}
if ((opcode & 0x20) == 0) {
/* 2OP */
/*
* note that variable-form je can have more than two arguments, though
* it is a 2OP
*/
opnum = opcode & 0x1F;
}
count = 0;
optypes = zm.get_code_byte();
if ((opnum == OP_CALL_VS2) || (opnum == OP_CALL_VN2)) {
optypebytes = 2;
optypes2 = zm.get_code_byte();
} else optypebytes = 1;
while (optypebytes-- != 0) {
optype = (optypes & 0xC0) >> 6;
if (optype == zm.OP_OMITTED) break;
operands[count++] = zm.get_operand(optype);
optype = (optypes & 0x30) >> 4;
if (optype == zm.OP_OMITTED) break;
operands[count++] = zm.get_operand(optype);
optype = (optypes & 0x0C) >> 2;
if (optype == zm.OP_OMITTED) break;
operands[count++] = zm.get_operand(optype);
optype = (optypes & 0x03);
if (optype == zm.OP_OMITTED) break;
operands[count++] = zm.get_operand(optype);
optypes = optypes2;
}
break;
case 0x80: /* short form */
optype = (opcode & 0x30) >> 4;
if (optype == zm.OP_OMITTED) {
/* 0OP */
opnum = opcode;
count = 0;
} else {
/* 1OP */
opnum = opcode & 0x8F;
count = 1;
operands[0] = zm.get_operand(optype);
}
break;
default: /* long form */
/* always 2OP */
opnum = opcode & 0x1F;
count = 2;
optype = ((opcode & 0x40) >> 6) + 1;
operands[0] = zm.get_operand(optype);
optype = ((opcode & 0x20) >> 5) + 1;
operands[1] = zm.get_operand(optype);
}
}
