Lisa assembler

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For Apple's 68000-based Lisa computer, see Apple Lisa.

The Lisa assembler (Lazerware's Interactive Symbolic Assembler), written by Randall Hyde (Randy Hyde) in the late 1970s, is an interactive MOS 6502 assembler for Apple II computers.

The latest version of Lisa, V3.2, is known to be both interactive and fast. A syntax mistake can be reported immediately in the edit mode. Lisa can compile about 30,000 lines of code in a minute on a 1 MHz computer.

Lisa, before v.3, was able to compile SWEET16 codes, a virtual 16-bit processor implemented as part of the Integer BASIC. However, Apple II's integer ROM was replaced by Monitor ROM since Apple II+.

The assembler also features "Randy's Hi-res Routines", a set of easy-to-use 2D computer graphics commands. Apple II's hi-res display pages (Hi-Res 1: 280 x 160 and Hi-Res 2: 280 x 192) were implemented by Steve Wozniak using merely 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 weird coloring properties (each pixel uses 1-bit, its color is determined by that bit's place in a byte and its neighboring pixel). These ready-made subroutines were created to help programmers.

Lisa has a built-in disassembler.