== AQB: A BASIC Compiler and IDE for Amiga Computers
=== Project Scope
An experiment in alternate history: what AmigaBASIC could have looked like,
had it been developed further tailored to the Amiga OS.
What AQB is not: AQB does not try to be a clone of any particular BASIC
dialect - neither QuickBASIC, FreeBASIC or VisualBASIC nor any particular Amiga
specific BASIC implementation like AmigaBASIC, ACE, HiSoft, GFA, Blitz or AMOS.
While it strives to be as compatible as possible with the Microsoft BASIC
family of languages (and certainly has many QuickBASIC traits) the primary
focus is on the creation of a modern, clean, Amiga OS-compliant, future-proof
BASIC that is tailored towards modern Amiga application development.
To be more specific, FreeBASIC is the source of many core AQB language
constructs (in many respects AQB can be considered a subset of FreeBASIC) with
inspiration for Amiga specific commands mainly from AmigaBASIC, ACE and HiSoft.
Main target is Amiga OS compliant application development.
Improvements over AmigaBASIC include:
* Advanced type system (including UDTs and Pointers, see below)
* Support for non-static functions and subs (enables recursion)
* Module support (similar to UNITs in TurboPascal, with full type safety and
dependencies) * Modern syntax inspired by FreeBASIC and VisualBASIC
* True native 68k compiler
* Integrated IDE besides compiler command line interface with
* syntax highlighting
* auto-indent
* folding support
* source level debugging
=== Requirements
* 3 MB RAM
* OS 2.0 (V36) or newer
=== Installation
Right now no installation is required. Just download a release LHA archive
(https://github.com/gooofy/aqb/releases) and unpack it wherever you like, but
keep the directory structure intact.
=== Latest Changes (0.8.2):
Improvements:
* runtime: WAVE, WAVE FREE, SOUND, SOUND WAIT, SOUND STOP, SOUND START commands
added
* runtime: WAVE() function added
* runtime: IFF8SVX LOAD WAVE, IFF8SVX READ WAVE commands added
* runtime: BITMAP MASK statement added
* runtime: CLEAR statement added
* runtime: MID$, UCASE$, LCASE$, INSTR, LEFT$, RIGHT$ functions added
* runtime: ABS function added
* runtime: EOF() function added
* runtime: CLS, LOCATE, SLEEP FOR, PRINT, PRINT#, INPUT, LINE INPUT moved from
\_aqb to \_brt
* runtime: INPUT#, LINE INPUT#, WRITE, WRITE# statements added
* runtime: DATE$, POINT functions added
* compiler: support pure interface modules that have no code
Bug Fixes:
* ide: EZRequest on source write fails instead of a plain exit()
* ide: ENDIF auto-indentation fixed
* examples: tetris code cleanup, use custom fonts
* compiler: fix float handling in DATA statements
* compiler: fix coord/coord2 error handling
* compiler: do not abort on type system inconsistencies (e.g. unresolved
forwarded types)
* compiler: check and resolve all forward ptrs
* compiler: fix err msg position for constant declaration expression
* compiler: fix string type coercion (fixes #17, thanks to Tom Wilson for
reporting this one)
* compiler: fix negative numeric literal handling in DATA statements
* compiler: fix string handling in DATA statements (fixes #18, thanks to Tom
Wilson for reporting this one)
* compiler: fix ENDIF SLE stack underflow
* runtime: fix INT() behavior (matches ACE now), add CLNG() to online help
* runtime: fix LINE INPUT
* use EXIT\_FAILURE for fatal error conditions (fixes issue #13 by polluks)
* add "$VER" version string
=== Type System
==== Basic types:
* Byte, UByte (8 bits)
* Integer, UInteger (16 bits)
* Long, ULong (32 bits)
* Single (32 Bit FFP floats)
==== Advanced types
* Static (C-like, fast) and dynamic (runtime bounds checking) arrays
* UDTs (structs)
* OOP (FreeBASIC like)
* Pointers (C-like, including function/sub pointers)
* Strings (0-terminated pointers to UByte, C-compatible)
=== Module System and Runtime
AQB tries to keep the set of commands that are built into the compiler to a
minimum and relies on its quite powerful module system to provide most of the
commands as part of the runtime system. This means that while the default
runtime strives to implement a modern QuickBASIC like dialect tailored to the
Amiga, it is quite possible to implement alternative runtime modules that could
provide AQB with a different "personality", e.g. one that is closer to
AmigaBASIC or GFA BASIC or even languages like BlitzBasic ot AMOS.
The goal for AQB's default runtime is to provide a rich set of commands
covering typical Amiga OS programming topics like GUI programming,
multitasking, graphics and audio combined with resource tracking and
error/exception handling. Future plans might also include an automated garbage
collector to make memory allocation easier and safer.
AQB is fully link-compatible with the Amiga 68k GCC compiler which means that
AQB modules can be implemented in C as well as BASIC (one could even
mix these languages within one module, i.e. implement some subprograms in
C while others in BASIC).
==== Intuition / Exec event handling
Since the default runtime wants to enable OS friendly programming no busy
waiting is used. Therefore the SLEEP command is used to process pending events,
i.e. you will need to call SLEEP regularly in your program, typically form a
main loop that could look like this:
WHILE running
SLEEP
WEND
For event processing you register subroutines using the ON ... CALL <function>
family of statements, e.g.
ON WINDOW CALL myWindowHandler
see https://github.com/gooofy/aqb/blob/master/examples/demo/gfx1.bas for a
simple example of this approach.
Interesting detail: since AQB supports C-like function pointers, the ON ...
CALL family of statements is not built into the compiler but part of the _aqb
runtime:
PUBLIC DECLARE SUB ON WINDOW CALL (BYVAL p AS SUB)
=== Code Generation and Target Systems
At the time of this writing classic 68k Amiga systems is the only compiler
target. The idea is to focus on one target and try to make AQB work really well
on this platform before expanding to other systems. The AQB compiler is
implemented from scratch in C based on Appel's 1997 book "Modern Compiler
Implementation in C" and tries to keep system requirements (RAM and CPU) low
while still producing somewhat sensible machine code. Originally the AQB code
was based on ComMouses's tiger compiler implementation
(https://github.com/ComMouse/tiger-compiler) which provided a very useful
starting point.
For future expansions to other platforms the current plan is to use an LLVM
based backend for all platforms powerful enough to run LLVM which is probably
true for most NG Amiga systems (AROS, AmigaOS 4 and MorphOS) and most likely
also for highly expanded classic Amiga systems (using accelerator cards
such as PiStom or Vampire).
As for the 68k compiler future plans include further reduction of its memory
footprint ideally to a point where it is useful on 1MB or even 512K Amiga
systems. At that point it might even make sense to implement a 6502 backend
targeting modern 8 bit systems like the MEGA65, Commander X16 or C256 Foenix.
=== Amiga OS System Programming in AQB
AQB datatypes are very similar to C (C-like strings, structs and pointers)
which makes usage of Amiga OS libraries and devices pretty seamless.
Data structures generally can be modeled 1:1 from their C counterparts, a
python script semi-automating the task of converting Amiga C library and device
headers to AQB is in the works. Here is a preview of what the resulting AQB
declarations typically look like:
[...]
TYPE ViewPort
AS ViewPort PTR NextViewPort
AS ColorMap PTR ColorMap
AS CopList PTR DspIns, SprIns, ClrIns
AS UCopList PTR UCopIns
AS INTEGER DWidth, DHeight, DxOffset, DyOffset
AS UINTEGER Modes
AS UBYTE SpritePriorities, ExtendedModes
AS RasInfo PTR RasInfo
END TYPE
TYPE Layer_Info
AS Layer PTR top_layer, check_lp
AS ClipRect PTR obs, FreeClipRects
AS LONG PrivateReserve1, PrivateReserve2
AS SignalSemaphore Lock
AS MinList gs_Head
AS INTEGER PrivateReserve3
AS VOID PTR PrivateReserve4
AS UINTEGER Flags
AS BYTE fatten_count, LockLayersCount
AS INTEGER PrivateReserve5
AS VOID PTR BlankHook, LayerInfo_extra
END TYPE
EXTERN GfxBase AS VOID PTR
DECLARE SUB Move (rp AS RastPort PTR, x AS INTEGER, y AS INTEGER) LIB -240
GfxBase (a1, d0, d1)
DECLARE SUB RectFill (rp AS RastPort PTR, xmin AS INTEGER, ymin AS INTEGER,
xmax AS INTEGER, ymax AS INTEGER) LIB -306 GfxBase (a1, d0, d1, d2, d3)
DECLARE SUB Draw (rp AS RastPort PTR, x AS INTEGER, y AS INTEGER) LIB -246
GfxBase (a1, d0, d1)
DECLARE SUB SetAPen (rp AS RastPort PTR, pen AS INTEGER) LIB -342 GfxBase
(a1, d0)
[...]
=== Benchmark Results
Measured on an A500 configuration (PAL 68000, 3MB RAM) in FS-UAE, Kickstart 1.3
|===
| Benchmark | AmigaBasic | GFA Basic 3.52 | BlitzBasic 2.15 |
HiSoft Basic 2 | AQB
| ctHLBench integer | 33.94s | 7.40s | 6.96s |
12.41s | 1.66s
| ctHLBench real | 23.90s | 6.88s | 4.99s |
4.46s | 3.12s
| fibonacci | no recursion | 54.60s | guru |
28.18 | 4.09s
|===
=== Source Code
https://github.com/gooofy/aqb
|
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