Color BASIC: Difference between revisions

Revision as of 14:02, 10 January 2009

Revision as of 03:02, 7 March 2009

Line 1:

{{Refimprove|date=March 2009}}

'''Color BASIC''' is the implementation of [[Microsoft BASIC]] that is included in the [[Read-only memory|ROM]] of the Tandy/Radio Shack [[TRS-80 Color ComputersComputer]]s ("CoCos") manufactured between 1980 and 1991. [[BASIC]] (Beginners All-purpose Symbolic Instruction Code) is a high level language with simple syntax that ismakes it easy for novices to write simple programs. BASIC is interpreted, that is, decoded as it is run. Because of this, it is simple to edit and [[debug]] but its performance is significantly lesslower than a compiled language such as [[C (programming language)|C]] or [[assembly language]].

==Background==

Color BASIC 1.0 was released with the original 4k TRS-80 Color Computer in 1980. It resides on 8k bytes of ROM, and is responsible for all 'housekeeping' duties on the system. This includes hardware initialization, memory management, etc. Like most implementations of BASIC, each line of code starts with a line number and consists of one or more statements with variables and operators. 16k of memory is required for the next level of BASIC, Extended Color BASIC. ("ECB") Extended BASIC is required for the floppy disk controller, which then gives you Disk Extended Color BASIC. ("DECB")

Color BASIC 1.0 was released with the original 4k TRS-80 Color Computer in 1980. It resides on 8k bytes of ROM, and is responsible for all 'housekeeping' duties on the system. This includes hardware initialization, memory management, etc. Like most implementations of BASIC, each line of code starts with a line number and consists of one or more statements with variables and operators.

16k of memory is required for the next level of BASIC, Extended Color BASIC. ("ECB")

Extended BASIC is required for the floppy disk controller, which then gives you Disk Extended Color BASIC. ("DECB")

==Variables==

Color BASIC understands one type of numeric variable and string variables. Variable names in Color BASIC have the first two characters significant. The first character of the variable name must be a letter. The second can be either a letter or number. String variables are indicated by adding a dollar sign ($) after the variable name.

===Examples===

A=5<br>

Line 27 ⟶ 22:

A(1)=1<br>

A$(1)="BOOKS"<br>

Multiple dimensions are separated by commas

Line 35 ⟶ 29:

==Operators and Symbols==

Color BASIC provides several operators for both mathematic and, (to a lesser extent), string operations.

Color BASIC provides several operators for both mathematic and (to a lesser extent) string operations

+ can be used to concatenate strings or for mathematical addition<br>

Line 95 ⟶ 88:

==Commands==

'''AUDIO [ON|OFF]''' Connects or disconnects cassette audio from the TV sound<br>

'''CLEAR ''variable space''[,''highest memory ___location'']''' reserves memory for string variables, and optionally, a machine language program<br>

Line 165 ⟶ 157:

==Documented ROM subroutines==

There are a few subroutines available for machine language programs in the Color BASIC ROM that are available for general purpose programming.

Line 174 ⟶ 165:

'''BLKOUT''', address [$A008]: writes a block to cassette<br>

'''JOYIN''', address [$A00A]: reads joystick values<br>

==References==