Tandy's Little Wonder (1993)(Farna Systems).pdf - TRS-80 Color ...

EXTENDED the CF83 FORTH language. This is one of themost important features of FORTH: you can extend andcustomize it to meet your own particular needs. And, you cando so almost without limit! (Except, of course, that you can’tuse the word until after you have defined it).CF83 FORTH is modular. Unlike other languages where youhave to buy the entire package whether you need it or not,CF83 FORTH is organized onto individual disks that you canbuy one or more at a time. You only buy what you need, andonly when you need it. As an additional savings, each module’sinstruction manual is stored on the module’s disk (printedmanuals are available though). Prices are significantly lowerwithout the printed manuals. You can view the stored manualon the screen and, if you need one, you can print a hardcopyon your own printer.CF83 FORTH is a 1983 Standard FORTH for the 64K CoCo2, 128K CoCo 3, and 512K CoCo 3, with at least onestandard single sided 35 track floppy disk drive. As ofJanuary 1993, the CF83 FORTH system included the followingmodules:CF83: FORTH-83 Standard Required Words. This moduleis the foundation - you must have this one for any of theothers to work).CF83-1: Technical Reference ManualCF83-2: FORTH TutorialCF83-3: Block Editor. You need a FORTH editor to writeyour programs in CF83 FORTH. Unless you can write yourown editor, you’d better get this one!CF83-4: Double Number Set. CF83 only handles 16-bitintegers by itself. This set lets you handle 32-bit integers.CF83-5: Assembler Set. Integrate machine code routinesthat have to be real fast with this full-featured assembler.CF83-6: System Extension Set. Helps you define newcontrol words more effectively.CF83-7: Controlled Reference Set. Words that performmany different functions. Includes recursion, block control,and system maintenance routines.CF83-8: Uncontrolled Reference Set. Includes case structure,string operations, printer control, and more.CF83-9: PMODE Graphics Set. Use PMODE graphics inprograms.CF83-12: Turns your CF83 FORTH programs into binaryfiles that will EXEC directly from BASIC. Includes systemsaving and general disk file handling & creation.The entire set could be purchased for as little as $120, notbad for such a high-level language. Most general users wouldonly need three or four modules though, bringing the costdown to under $50. Just recently, however, the main FORTHmodule (CF83) was placed into the Public Domain, makingthis language even more attractive! Contact BDS Softwarefor more info on PD modules.page 46Tandy's Little WonderModules that were under development at the time this waswritten include:CF83-10: HMODE Graphics Set. Use high-resolution CoCo3 graphics.CF83-11: Sound, Joysticks, Timer, & Random NumbersCF83-13: Floating Point Numbers SetCF83-14: Trigonometry SetCF83-15: Complex Numbers SetREFERENCE:(1) Medding, Olaf; “FORTH-Based Message Service”;FORTH DIMENSIONS, Volume XIV, Number 5, January-February 1993; FORTH Interest Group, P.O. Box 2154,Oakland, CA. 94621FORTH09 is a CF83 FORTH implementaion for the OS-9operating system. It is also available from BDS Software.Actual machine language (M/L) and assembly language(A/L) programming is beyond the scope of thisbook. Machine Language refers to the actual code that theMPU reads directly. One CAN write directly in this code,but most programmers use an Assembler to put the codetogether, thus the term Assembly Language (M/L and A/Lare usually used interchangeably).Writing directly in M/L requires poking the certain values inthe correct memory locations. This is exactly what is beingdone when a BASIC program has a routine like the one shownin the double speed program (PEEK, POKE, EXEC Enhancements,lines 440-480). A data set (in this case A$)contains a list of values that is then poked into memory by ashort BASIC program.An assembler makes life easier for the programmer. Theprogram is written in mnemonic instruction code with aneditor (usually bundled with the assembler... Tandy'sEDTASM+ name comes from EDiTor/ASseMbler). Theinstruction code is a set of instructions that are programedinto the CPU itself. These instructions operate on andaccess data in different ways through addressing modes. The6809 has 59 instructions and ten addressing modes for atotal of 1464 different operations. Variations of thesemodes bring the total number of modes up to 19. This codemust then be assembled into a list of binary data (m/l code)that the CPU can use directly.Mnemonic instructions are abbreviations of what the commandactually does. The instruction itself (ADDB, forexample) is called the "opcode" (operation code). This isfollowed by a value for the instruction to act on or with,called the "operand" or argument. Together, the opcode andoperand define exactly what the instruction does. The mnemonic"ADDB #1" means "add the contents of register B in