===== Commodore PET - Software Development =====

The //modern// way... using optimising C cross-compiler on Linux.

This is easier than expected, just install [[https://cc65.github.io/|CC65]]. On any modern Linux, this is as easy as:

<code>
$ apt-get install cc65
</code>

You then get cc65 (the C compiler), ca65 (the assembler) and ld65 (the linker). They work pretty much the same as any modern toolset:

   * Compile your **.C** source code using //cc65//, which will emit a **.S** assembly file
   * Assemble your **.S** assembly listing using //ca65//, which will emit a **.o** binary object file
   * Link your **.o** object files using //ld65//, possibly including the cc65 standard library, which will emit a **.prg** executable

Here's a simple //makefile// to get started with development. It assumes you have a **./src** folder with your C source code and that you resulting binary will be placed in **./bin**. Alter the paths to the location of the cc65 installation as appropriate:

<code>
# Names of the compiler and friends
CC	= cc65
AS	= ca65
LD 	= ld65

# libraries and paths
INCLUDES = --include-dir /usr/share/cc65/include
LIBS	 = --lib /usr/share/cc65/lib/pet.lib

# Compiler flags
ASM_FLAGS= --target pet
LDFLAGS	= --target pet
CFLAGS 	= --target pet -O -Oi -Or -Os

# What our application is named
TARGET	= game.prg

all: $(TARGET)

# The main application
OBJFILES = src/test.o

$(TARGET):  $(OBJFILES)
	$(LD) $(LDFLAGS) --obj $(OBJFILES) $(LIBS) -o bin/$(TARGET)
	
################################
# Main code
################################
src/test.s: src/test.c
	$(CC) $(CFLAGS) $(INCLUDES) src/test.c

src/test.o: src/test.s
	$(AS) $(ASM_FLAGS) src/test.s

###############################
#
# Clean up
#
###############################
clean:
	rm -f src/*.o
	rm -f bin/$(TARGET)
</code>

==== Documentation & Library Reference ====

   * Commodore PET specific functions (which are very few) are defined in **pet.h**, found in the //include// directory of the cc65 installation.
   * CC65 implementation guidance can be found [[https://cc65.github.io/doc/|here]].
   * The CC65 standard library can be found [[https://cc65.github.io/doc/funcref.html|here]].