zoltan-balazs / jabyinja Goto Github PK

For now a simple "Hello World" programming being interpreted is fine.
Everything is got to start somewhere.

Due to indexing out of the stack an IndexOutOfRange exception can happen.

For example, INVOKEs should push their result to the stack (they do not do that currently)

Due to not being able to convert Objects as easily, we first need to convert it to appropriate type first, then convert it again.

Due to using builtin long's and basic power functions, floating point precision breaks fairly easily.

Rethinking if the current structure is good.
Is it clean enough?
Is there not too much repetition?

The current Main.java file is being parsed incorrectly.

A BufferUnderflowException is being triggered, meaning that either readShort or readInt cannot read enough bytes from the buffer.

This is due https://docs.oracle.com/javase/specs/jvms/se7/html/jvms-4.html#jvms-4.4.5

A Double / Long entry takes up 2 places in the constant pool as they both take up 8 bytes

Due to reading in a signed integer, the low bytes of a long can be incorrect fairly easily.

Parse ClassFile as per language specifications: https://docs.oracle.com/javase/specs/jvms/se7/html/jvms-4.html

Converting a removed Object from the stack isn't as easy as just casting it. We need to convert it to a Number object first and call the appropriate method for the value.

Due to long/double values being 8 byte wide, they take up 2 physical spaces in the local variables

To better ensure that the Class file is parsed correctly, testing must be implemented.

• As of the issue's opening, I have not figured out what testing library to use
• I need reproducible cases to check validity of Class file parsing
• Also need some sample files to parse (probably "Hello World", simple List application, etc.)

All DUP instructions have an off-by-one indexing error