NESHLA:
The High Level, Open Source,
6502 Assembler for the Nintendo Entertainment System

NESHLA is an assembler for the Nintendo NES which gives the features of high level languages such as C without sacrificing any efficiency or speed. It structures and simplifies coding the NES, while still using assembly language. Compilers are inefficient for low end systems such as the NES. Even with optimizers, they would never produce code for fast action games or capable of tapping deep into the NES. It's the best of both worlds!

The assembler is packed with features, macros, functions and header files to make development quick and easy. It does the job, and has made my development on the game Grand Theftendo much easier. However, there is still room for an endless amount of features, tweaks and additions. That's where you come in! Anyone interested in joining the project and contributing is more than welcome! It's written in standard C and should compile and work on any platform with little or no modification. So whatever platform is your choice for development, you can help out!

For more information on the language, have a look at the documentation.

Download

• Binary
  • (neshla-20050417-bin-win32.zip)
• Source
  • (neshla-20050417-src-win32.zip)

The Open Source Project

There are a number of features I would love to see added to NESHLA.

• It would be quite easy to modify it to accommodate any other 6502 system (heck, any other assembly language too). If anyone wants to make a C64HLA, Atari 2600 HLA, or anything else, go right ahead!
• The assemble time is quite fast for a large game on new PCs, but to accommodate slower ones, it would be very useful for an object file/makefile Addison to be implemented.
• When performing arithmetic on a label (such as _somedata+1), the label must currently be declared prior to the use. It would be great for the arithmetic handler to be updated so it can be performed on any label no matter where it's declared.
• The documentation is slightly out of date, and many features have been added since it was written. It would be great for someone to finish it.
• More macros, library functions, and header files are always welcome!

URLs

http://www.bripro.com
http://www.sourceforge.net/projects/neshla
http://neshla.sf.net

NESHLA Programming Manual

• NES Programming FAQ and Important Pointers
  • Introduction
  • General PPU Registers
  • Name and Attribute Tables (the background graphics)
  • Scrolling

• Preprocessor Keywords
  • Introduction
• Defines
• Messages
• Files
• ROM and RAM Banks and Blocks
• Padding
• Interrupt Vectors
• iNES Header

• Variable Declaration and Use
  • Introduction
  • Variable Declarations & Manipulators

• Function Declaration and Use
  • Introduction
  • Declaring Functions
  • return and noreturn
  • Parameters
  • Interrupt Type Declaring
  • Calling Functions

• Integers and Arithmetic Operations
  • Introduction
  • Integers
  • Arithmetic Operations
    • Operators
    • Keywords
    • Examples

• Conditional Statements
  • Introduction
  • If Statements
  • While Statements
  • Do While Statements
  • Forever Statements
  • Switch Statements

• NESHLA Code Library
  • Introduction
  •  LIB_RAM.AS
  •  STD.H (Standard 6502 Functions, Macros and Defines)
    •  STD_ASSIGNMENT.H
    •  STD_BITWISE.H
    •  STD_BOOLEAN.H
    •  STD_JUMPS.AS
    •  STD_MATH.AS
      •  STD_MATH.H
    •  STD_MEMORY.AS
      •  STD_MEMORY.H
    •  STD_PALETTE.AS
    •  STD_STACK.H
  •  NES.H (Standard NES Functions, Macros and Defines)
    •  NES_AUDIO.H
    •  NES_IO.H
    •  NES_MAPPERS.H
    •  NES_SYSTEM.H
    •  NES_VIDEO.H

• Compiler Options
  • Introduction

Brian Provinciano