pskupinski/65816.js

A JavaScript 65816 Microprocessor Emulator

65816.js's Issues

STA(d,S),Y is broken

STA(d,S),Y instead of storing data where expected, loads it from the correct location but then mistakenly uses it as an address and stores A at some random spot in memory.

No support for loading binary files

Right now the emulator only takes strings. There should also be support for loading a binary from a given URL and interpreting that.

https://github.com/mozilla/pdf.js/blob/master/src/core.js#L28 - is a good example of this functionality.

No performance tests exist to measure gains made

Tests need to be added to allow for an individual to measure performance gains or regressions against a previous version.

TXA and TYA are broken

SEP #$30
LDA #1
XBA
LDX #3 
TXA
REP #$30
STA $700

Observed:

[$701]:[$700] contains $0003

Expected:

[$701]:[$700] should contain $0103. An 8-bit transfer should not touch the high bits of the register.

Unit tests failing on IE6-9

As of right now 189 tests fail on both IE6 and IE9 showing that some sort of investigation into why should be done.

cpu.js is far too large

A serious effort needs to be put into cutting down the number of lines of code in cpu.js.

A great deal of code follows a similar pattern and could be turned into generic, reusable functions and customized for the operation being performed. The focus should be on writing a library of functions for the different addressing modes and using those instead of using roughly the same code in plenty of places.

Unit tests do not cover all of the functionality of the emulator

For many instructions there do not exist any unit tests at all and this needs to be resolved.