com.adobe.xfa.formcalc

Class Instruction

java.lang.Object

com.adobe.xfa.formcalc.Instruction

public final class Instruction
extends Object

The class Instruction defines all the instructions that the FormCalc virtual machine is capable of executing, as a collection of static methods. Each instruction corresponds to an opcode of this virtual machine.

An execution path of the virtual machine is just a sequence of instructions stored in FormCalc's virtual code space. Each sequence is terminated with an Stop instruction, to represent the end of an execution path.

All instructions have a common interface, consisting of: a the FormCalc YYPARSENAME. Since the FormCalc virtual machine is a stack machine, i.e., its fetches its operand(s) from a runtime stack, and pushes its result back onto the runtime stack, most instructions are single word instructions. A few instructions, like Load, In, Out and Call are multi-word instructions -- some of their operands are stored in the words following the opcode. Other instructions, like If, For and While, also multi-word instructions, contain control flow information to the different execution paths inherent of conditional and iterative instructions.

Method Summary

Modifier and Type	Method and Description
boolean	debugBreakPoint(int nScriptID, int nLine, boolean bSet) Set or clear a debug break-point.
boolean	debugCommand(com.adobe.xfa.formcalc.CalcParser oParser, int eCmd) Set internal state to enable either step-over, step-into or step-out.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

debugBreakPoint

public boolean debugBreakPoint(int nScriptID,
                               int nLine,
                               boolean bSet)

Set or clear a debug break-point. It sets or clears a flag in the moDebugLineNo array, which is an array of line numbers parallel to the moCodeBase array.

Parameters:

nLine - line of source code.

bSet - true to set a break-point, false to clear it.

Returns:

true if successful.

debugCommand

public boolean debugCommand(com.adobe.xfa.formcalc.CalcParser oParser,
                            int eCmd)

Set internal state to enable either step-over, step-into or step-out. The debug-mode execution loop calls the debug host's Stopped method when mnDebugStopAtStackDepth is greater than or equal to the current stack depth.

Parameters:

oParser - the FormCalc parser.

eCmd - a value of the CalcDebugCommand enum representing step-over, step-into or step-out.

Returns:

true if successful.