title: "FastBasic Cross Compiler - Fast BASIC interpreter for the Atari 8-bit computers"

FastBasic Cross Compiler

This is the FastBasic cross compiler. It takes a basic sources and compiles to
an assembly file, and then uses the CA65 assembler and LD65 linker (from the
CC65 tools) to build an Atari executable.

Installation

Extract the FastBasic compiler on any folder. The CC65 tools are already
included in the archive.

Basic Usage

For simple compilation of BAS files to XEX (Atari DOS executable), use the
included fb and fb-int scripts.

• On Linux:

  /path/to/fb myprog.bas
  

  or:

  /path/to/fb-int myprog.bas
  

• On Windows:

  C:\path\to\fb myprog.bas
  

  or:

  C:\path\to\fb-int myprog.bas
  

There are two compilers, one for the full version fastbasic-fp, used with the
fb script, and another for the integer only version fastbasic-int, used
with the fb-int script. The advantage of the integer only version is that it
produces smaller executables.

The script generates three files from the basic source:

• XEX file, standard Atari 8-bit executable.

• ASM file, the assembly source.

• LBL file, a list of labels, useful for debugging. This file includes a label
  for each line number in the basic source.

The compilation is a three step process, the included script does each step in
turn:

• The included compiler reads the basic source and produces an assembly file:

  fastbasic-fp myprog.bas myprog.asm

• The CA65 assembler is used to assemble to an object file:

  ca65 -t atari -g myprog.asm -o myprog.o

• The LD65 linker joins the object file with the runtime library to generate the XEX:

  ld65 -C /path/to/fastbasic.cfg myprog.o -o myprog.xex /path/to/fastbasic-fp.lib

Advanced Usage

Passing options to the compiler

The compiler scripts fb and fb-int allows passing options to the compiler,
allowed options are:

• -v
  Shows the compiler version.

• -n
  Disable all the optimizations, the produced code will be the same as the
  native IDE. This is useful to debug problems with the optimizations passes,
  should not be used normally.

• -prof
  Helps profiling the compiler generated code. Outputs statistics of the most
  used tokens and token pairs.

• -d
  Enable parser debug options. This is only useful to debug parser, as it
  writes the full parsing tree with all the tried constructs.

• -l
  In addition to compiling the file, also write to standard output a prettified
  version of the input program, with all abbreviations expanded, one statement
  per line and indented code. This is useful to examine compiler errors in heavily
  abbreviated code.

• -h
  Shows available compiler options.

• -C:linker-file.cfg
  Use a different linker configuration file than the default.

• -S:address
  Sets the start address of the compiled binary. The default value is $2000,
  set in the configuration file fastbasic.cfg. You can specify a different
  address to allow for a bigger DOS, or to have more memory available if you
  don't use a DOS. The address can be specified as decimal or hexadecimal with
  0x at front.

• -X:ca65-option
  Passes the given option to the CA65 assembler. See the CA65 documentation for
  valid options, some useful options are listed bellow:

  • -X:-Ipath
    Adds a path to search for assembly included files, used in your custom ASM
    sources.

  • -X:-Dsymbol
    Define an assembly symbol, used in custom ASM sources.

  When using -X: you can't leave spaces for the option, use multiple -X:
  
  for each space separated argument. For example, you can use -X:-I -X:path
  
  as two options or -X:-Ipath, as both will pass the same option and value.

Linking other assembly files

The compiler support linking to external assembly modules, you can pass them to
the fb command line:

fb myprog.bas myasm.asm

This will compile myprog.bas to myprog.asm and then assemble the two files
together using CA65 and LD65. You can pass multiple .asm (or .o) files to the
command line, but only one basic file.

From the FastBasic source, you can reference any symbol via @name, for example:

' FastBasic code
'
? "External USR sample:"
? USR( @Add_10, 25 )

The ASM file must export the ADD_10 (always uppercase) symbol, for example:

; Assembly module
  .export ADD_10

.proc ADD_10
  pla   ; Parameters are pased over the stack, in reverse order
  tax
  pla
  clc
  adc #10
  bcc no
  inx
no:
  ; Return value in A/X registers
  rts
.endproc

You can also export ZP symbols, to import them use @@name.