Lazer's Interactive Symbolic Assembler (Lisa) is an interactive 6502

assembler Assembler may refer to: Arts and media * Nobukazu Takemura, avant-garde electronic musician, stage name Assembler * Assemblers, a fictional race in the ''Star Wars'' universe * Assemblers, an alternative name of the superhero group Champions of A ...

for

Apple II The Apple II (stylized as ) is an 8-bit home computer and one of the world's first highly successful mass-produced microcomputer products. It was designed primarily by Steve Wozniak; Jerry Manock developed the design of Apple II's foam-m ...

computers written by

Randall Hyde Randall Hyde (born 1956) is best known as the author of ''The Art of Assembly Language'', a popular book on assembly language programming. He created the Lisa assembler in the late 1970s and developed the High Level Assembly (HLA) language. Bio ...

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

MHz The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), equivalent to one event (or cycle) per second. The hertz is an SI derived unit whose expression in terms of SI base units is s−1, meaning that one he ...

computer, a speed achieved due to the editor's pre-parsing of the source code. Lisa, before v.3, was able to assemble

SWEET16 SWEET16 is an interpreted byte-code instruction set invented by Steve Wozniak and implemented as part of the Integer BASIC ROM in the Apple II series of computers. It was created because Wozniak needed to manipulate 16-bit pointer (computer prog ...

codes, a virtual

16-bit 16-bit microcomputers are microcomputers that use 16-bit microprocessors. A 16-bit register can store 216 different values. The range of integer values that can be stored in 16 bits depends on the integer representation used. With the two mos ...

processor implemented as part of the

Integer BASIC Integer BASIC is a BASIC interpreter written by Steve Wozniak for the Apple I and Apple II computers. Originally available on cassette for the Apple I in 1976, then included in ROM on the Apple II from its release in 1977, it was the first version ...

. 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 is the computer-based generation of digital images—mostly from two-dimensional models (such as 2D geometric models, text, and digital images) and by techniques specific to them. It may refer to the branch of computer ...

commands. Apple II's hi-res display pages (Hi-Res 1: 280 × 160 and Hi-Res 2: 280 × 192) were implemented by

Steve Wozniak Stephen Gary Wozniak (; born August 11, 1950), also known by his nickname "Woz", is an American electronics engineer, computer programmer, philanthropist, inventor, and technology entrepreneur. In 1976, with business partner Steve Jobs, he c ...

using two

TTL TTL may refer to: Photography * Through-the-lens metering, a camera feature * Zenit TTL, an SLR film camera named for its TTL metering capability Technology * Time to live, a computer data lifespan-limiting mechanism * Transistor–transistor lo ...

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 that it's place in a byte and its neighboring pixel). These ready-made

subroutine In computer programming, a function or subroutine is a sequence of program instructions that performs a specific task, packaged as a unit. This unit can then be used in programs wherever that particular task should be performed. Functions may ...

s were created to help programmers. Lisa has a built-in

disassembler A disassembler is a computer program that translates machine language into assembly language—the inverse operation to that of an assembler. A disassembler differs from a decompiler, which targets a high-level language rather than an assembly lan ...

. 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 The W65C816S (also 65C816 or 65816) is an 8/16-bit microprocessor (MPU) developed and sold by the Western Design Center (WDC). Introduced in 1985, the W65C816S is an enhanced version of the WDC 65C02 8-bit computing, 8-bit MPU, itself a CMOS enha ...

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,

External links

Lisa history and PD download
at Apple Oldies by Bill Buckels
How to Program the Apple II Using 6502 Assembly Language, with an Introduction to Sweet-16, 2nd Printing, December 1982, by Randy Hyde
Assemblers Apple II software {{programming-software-stub