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28
docs/source/index.rst
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@ -143,6 +143,7 @@ Design principles and features
still able to directly use memory addresses, CPU registers and ROM subroutines,
and inline assembly to have full control when every cycle or byte matters
- Arbitrary number of subroutine parameters (constrained only by available memory)
- Nested subroutines can access variables from outer scopes, this avoids the need and overhead to pass everything via parameters
- Complex nested expressions are possible
- Values are typed. Types supported include signed and unsigned bytes and words, arrays, strings and floats.
- No dynamic memory allocation or sizing! All variables stay fixed size as determined at compile time.
@ -158,7 +159,7 @@ Design principles and features
- The compiler tries to optimize the program and generated code, but hand-tuning of the
performance or space-critical parts will likely still be required. This is supported by
the ability to easily write embedded assembly code directly in the program source code.
- There are many built-in functions such as ``sin``, ``cos``, ``rnd``, ``abs``, ``min``, ``max``, ``sqrt``, ``msb``, ``rol``, ``ror``, ``swap``, ``memset``, ``memcopy``, ``sort`` and ``reverse``
- There are many built-in functions, such as ``sin``, ``cos``, ``rnd``, ``abs``, ``min``, ``max``, ``sqrt``, ``msb``, ``rol``, ``ror``, ``swap``, ``memset``, ``memcopy``, ``sort`` and ``reverse``
.. _requirements:
@ -167,26 +168,25 @@ Required tools
--------------
`64tass <https://sourceforge.net/projects/tass64/>`_ - cross assembler. Install this on your shell path.
A recent .exe version of this tool for Windows can be obtained from my `clone <https://github.com/irmen/64tass/releases>`_ of this project.
For other platforms it is very easy to compile it yourself (make ; make install).
It's very easy to compile yourself.
A recent precompiled .exe for Windows can be obtained from my `clone <https://github.com/irmen/64tass/releases>`_ of this project.
A **Java runtime (jre or jdk), version 8 or newer** is required to run the packaged compiler.
If you're scared of Oracle's licensing terms, most Linux distributions ship OpenJDK instead
and for Windows it's possible to get that as well. Check out `AdoptOpenJDK <https://adoptopenjdk.net/>`_ for
downloads.
A **Java runtime (jre or jdk), version 8 or newer** is required to run the prog8 compiler itself.
If you're scared of Oracle's licensing terms, most Linux distributions ship OpenJDK instead.
Fnd for Windows it's possible to get that as well. Check out `AdoptOpenJDK <https://adoptopenjdk.net/>`_ .
Finally: a **C-64 emulator** (or a real C-64 ofcourse) to run the programs on. The compiler assumes the presence
of the `Vice emulator <http://vice-emu.sourceforge.net/>`_.
Finally: a **C-64 emulator** (or a real C-64 ofcourse) can be nice to test and run your programs on.
The compiler assumes the presence of the `Vice emulator <http://vice-emu.sourceforge.net/>`_.
.. important::
**Building the compiler itself:** (*Only needed if you have not downloaded a pre-built 'fat-jar'*)
(re)building the compiler itself requires a recent Kotlin SDK.
The compiler is developed using the `IntelliJ IDEA <https://www.jetbrains.com/idea/>`_
IDE from Jetbrains, with the Kotlin plugin (free community edition of this IDE is available).
But a bare Kotlin SDK installation should work just as well.
(Re)building the compiler itself requires a recent Kotlin SDK.
The compiler is developed using `IntelliJ IDEA <https://www.jetbrains.com/idea/>`_ ,
but only a Kotlin SDK installation should work as well, because the gradle tool is
used to compile everything from the commandline.
Instructions on how to obtain a working compiler are in :ref:`building_compiler`.
Instructions on how to obtain a prebuilt compiler are in :ref:`building_compiler`.
.. toctree::

107
docs/source/programming.rst
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@ -12,57 +12,56 @@ Elements of a program
---------------------
Program
Consists of one or more *modules*.
Consists of one or more *modules*.
Module
A file on disk with the ``.p8`` suffix. It contains *directives* and *code blocks*.
Whitespace and indentation in the source code are arbitrary and can be tabs or spaces or both.
You can also add *comments* to the source code.
One moudule file can *import* others, and also import *library modules*.
A file on disk with the ``.p8`` suffix. It can contain *directives* and *code blocks*.
Whitespace and indentation in the source code are arbitrary and can be mixed tabs or spaces.
A module file can *import* other modules, including *library modules*.
Comments
Everything after a semicolon ``;`` is a comment and is ignored by the compiler.
If the whole line is just a comment, it will be copied into the resulting assembly source code.
This makes it easier to understand and relate the generated code. Examples::
A = 42 ; set the initial value to 42
; next is the code that...
Everything after a semicolon ``;`` is a comment and is ignored by the compiler.
If the whole line is just a comment, this line will be copied into the resulting assembly source code for reference.
Directive
These are special instructions for the compiler, to change how it processes the code
and what kind of program it creates. A directive is on its own line in the file, and
starts with ``%``, optionally followed by some arguments.
These are special instructions for the compiler, to change how it processes the code
and what kind of program it creates. A directive is on its own line in the file, and
starts with ``%``, optionally followed by some arguments.
Code block
A block of actual program code. It defines a *scope* (also known as 'namespace') and
can contain Prog8 *code*, *variable declarations* and *subroutines*.
More details about this below: :ref:`blocks`.
A block of actual program code. It has a starting address in memory,
and defines a *scope* (also known as 'namespace').
It contains variables and subroutines.
More details about this below: :ref:`blocks`.
Variable declarations
The data that the code works on is stored in variables ('named values that can change').
The compiler allocates the required memory for them.
There is *no dynamic memory allocation*. The storage size of all variables
is fixed and is determined at compile time.
Variable declarations tend to appear at the top of the code block that uses them.
They define the name and type of the variable, and its initial value.
Prog8 supports a small list of data types, including special 'memory mapped' types
that don't allocate storage but instead point to a fixed location in the address space.
The data that the code works on is stored in variables ('named values that can change').
The compiler allocates the required memory for them.
There is *no dynamic memory allocation*. The storage size of all variables
is fixed and is determined at compile time.
Variable declarations tend to appear at the top of the code block that uses them.
They define the name and type of the variable, and its initial value.
Prog8 supports a small list of data types, including special 'memory mapped' types
that don't allocate storage but instead point to a fixed location in the address space.
Code
These are the instructions that make up the program's logic. There are different kinds of instructions
('statements' is a better name):
These are the instructions that make up the program's logic.
Code can only occur inside a subroutine.
There are different kinds of instructions ('statements' is a better name) such as:
- value assignment
- looping (for, while, repeat, unconditional jumps)
- conditional execution (if - then - else, when, and conditional jumps)
- subroutine calls
- label definition
- value assignment
- looping (for, while, repeat, unconditional jumps)
- conditional execution (if - then - else, when, and conditional jumps)
- subroutine calls
- label definition
Subroutine
Defines a piece of code that can be called by its name from different locations in your code.
It accepts parameters and can return a value (optional).
It can define its own variables, and it is even possible to define subroutines nested inside other subroutines.
Their contents is scoped accordingly.
Nested subroutines can access the variables from outer scopes.
This removes the need and overhead to pass everything via parameters.
Label
This is a named position in your code where you can jump to from another place.
@ -90,16 +89,20 @@ Scope
Blocks, Scopes, and accessing Symbols
-------------------------------------
**Blocks** are the top level separate pieces of code and data of your program. They are combined
into a single output program. No code or data can occur outside a block. Here's an example::
**Blocks** are the top level separate pieces of code and data of your program. They have a
starting address in memory and will be combined together into a single output program.
They can only contain *directives*, *variable declarations*, *subroutines* and *inline assembly code*.
Your actual program code can only exist inside these subroutines.
(except the occasional inline assembly)
main $c000 {
; this is code inside the block...
}
Here's an example::
main $c000 {
; this is code inside the block...
}
The name of a block must be unique in your entire program.
Also be careful when importing other modules; blocks in your own code cannot have
Be careful when importing other modules; blocks in your own code cannot have
the same name as a block defined in an imported module or library.
If you omit both the name and address, the entire block is *ignored* by the compiler (and a warning is displayed).
@ -109,7 +112,7 @@ want to work on later, because the contents of the ignored block are not fully p
The address can be used to place a block at a specific location in memory.
Usually it is omitted, and the compiler will automatically choose the location (usually immediately after
the previous block in memory).
The address must be >= ``$0200`` (because ``$00``--``$ff`` is the ZP and ``$100``--``$200`` is the cpu stack).
It must be >= ``$0200`` (because ``$00``--``$ff`` is the ZP and ``$100``--``$1ff`` is the cpu stack).
.. _scopes:
@ -133,14 +136,13 @@ Scopes are created using either of these two statements:
- subroutines (nested named scope)
.. note::
In contrast to many other programming languages, a new scope is *not* created inside
Unlike many other programming languages, a new scope is *not* created inside
for, while and repeat statements, nor for the if statement and branching conditionals.
This is a bit restrictive because you have to think harder about what variables you
want to use inside a subroutine. But it is done precisely for this reason; memory in the
target system is very limited and it would be a waste to allocate a lot of variables.
Right now the prog8 compiler is not advanced enough to be able to 'share' or 'overlap'
variables intelligently by itself. So for now, it's something the programmer has to think about.
This can be a bit restrictive because as a programmer you have to think harder about what variables you
want to use inside a subroutine. But it is done precisely for this reason: memory in prog8's
target systems is usually very limited and it would be a waste to allocate a lot of variables.
The prog8 compiler is not yet advanced enough to be able to share or overlap
variables intelligently. So for now that is something the programmer has to think about.
Program Start and Entry Point
@ -159,12 +161,12 @@ taking no parameters and having no return value.
As any subroutine, it has to end with a ``return`` statement (or a ``goto`` call)::
main {
sub start () {
; program entrypoint code here
return
}
}
main {
sub start () {
; program entrypoint code here
return
}
}
The ``main`` module is always relocated to the start of your programs
@ -175,7 +177,6 @@ calls with the SYS statement.
Variables and values
--------------------

5
docs/source/syntaxreference.rst
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@ -172,13 +172,13 @@ Code blocks
-----------
A named block of actual program code. Itefines a *scope* (also known as 'namespace') and
can contain Prog8 *code*, *directives*, *variable declarations* and *subroutines*::
can only contain *directives*, *variable declarations*, *subroutines* or *inline assembly*::
<blockname> [<address>] {
<directives>
<variables>
<statements>
<subroutines>
<inline asm>
}
The <blockname> must be a valid identifier.
@ -191,7 +191,6 @@ Also read :ref:`blocks`. Here is an example of a code block, to be loaded at ``
}
Labels
------

2
docs/source/todo.rst
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@ -11,7 +11,7 @@ Memory Block Operations integrated in language?
array/string memory block operations?
- vector inc/dec/add/sub/mul/div...? (on array or string):
arrayvar++ / arrayvar-- / arrayvar += 2 / arrayvar -= 2 / arrayvar *= 3 / arrayvar /= 3
``arrayvar++ / arrayvar-- / arrayvar += 2 / arrayvar -= 2 / arrayvar *= 3 / arrayvar /= 3``
- array operations
copy (from another array with the same length), shift-N(left,right), rotate-N(left,right)