View source for Lazer's Interactive Symbolic Assembler

<!-- Deleted image removed: [[File:Lisa26.gif|right|{{Deletable image-caption|1=Wednesday, 4 March 2009|date=May 2012}}]] -->
'''Lazer's Interactive Symbolic Assembler''' ('''Lisa''') is an interactive 6502 [[Assembler (computing)|assembler]] for Apple II computers written by Randall Hyde in the late 1970s.

The latest version of Lisa for 8-bit code is V3.2. Lisa includes an integrated editor with syntax checking. Lisa can assemble up to 30,000 lines of code in a minute on a 1 [[Megahertz|MHz]] computer, a speed achieved due to the editor's pre-parsing of the source code.

Lisa, before v.3, was able to assemble [[SWEET16]] codes, a virtual [[16-bit|16-bit]] processor implemented as part of the [[Integer BASIC]]. However, the Apple II's Integer BASIC ROMs were replaced by Applesoft BASIC ROMs since the Apple II+, and the latter didn't contain the SWEET16 interpreter code.

The assembler also features "Randy's Hi-res Routines", a set of [[2D computer graphics|2D computer graphics]] commands. Apple II's hi-res display pages (Hi-Res 1: 280 × 160 and Hi-Res 2: 280 × 192) were implemented by [[Biography:Steve Wozniak|Steve Wozniak]] using two TTL chips. Therefore, a software programmer has to deal with the discontinuous addressing of screen pixels (a full screen is split into three parts horizontally) and each pixel's coloring properties (each pixel uses 1-bit, its color is determined by its place in a byte and its neighboring pixel). These ready-made [[Subroutine|subroutine]]s were created to help programmers.

Lisa has a built-in [[Disassembler|disassembler]].

An enhanced version of Lisa, called Lisa 8/16, was developed for the Apple IIgs It has a mouse-based UI and support for the 65816 CPU.

All versions of LISA use a custom interface editor that stores source code in a tokenized form, which makes the source files smaller on disk and in memory.

== References ==
* Ward Douglas Maurer, ''APPLE assembly language with Lazerware software'', Computer Science Press, 1984, {{ISBN|0-914894-82-X}}

== External links ==
* [http://www.appleoldies.ca/anix/index.htm#lisa Lisa history and PD download] at Apple Oldies by Bill Buckels
* [https://www.scribd.com/doc/2429815/Using-6502-Assembly-Language-by-Randy-Hyde How to Program the Apple II Using 6502 Assembly Language, with an Introduction to Sweet-16, 2nd Printing, December 1982, by Randy Hyde]

[[Category:Assemblers]]



{{Sourceattribution|Lazer's Interactive Symbolic Assembler}}