6809 Simulator/Emulator
=======================

sbc09 stands for Lennart Benschop 6809 Single Board Computer.
It contains a assembler and simulator for the Motorola M6809 processor.

copyleft (c) 1994-2014 by the sbc09 team, see AUTHORS for more details.
license: GNU General Public License version 2, see LICENSE for more details.


Forum thread: http://archive.worldofdragon.org/phpBB3/viewtopic.php?f=8&t=4880


The first file of this shell archive contains C source, the second part
conttains example programs that can be run on the simulator.


Usage of a09 and v09 read /doc/sbc09.creole !



a09.c the 6809 assembler. It's fairly portable (ansi) C. It works on both
      Unix and DOS (TC2.0).

      Features of the assembler.
      - generates binary file starting at  the first address
        where code is actually generated. So an initial block of RMB's
        (maybe at a different ORG) is not included in the file.
      - Accepts standard syntax.
      - full expression evaluator.
      - Statements SET, MACRO, PUBLIC, EXTERN IF/ELSE/ENDIF INCLUDE not yet
        implemented. Some provisions are already made internally for macros
        and/or relocatable objects.

V09.c  the 6809 simulator. Loads a binary image (from a09) at adress $100
       and starts executing. SWI2 and SWI3 are for character output/input.
       SYNC stops simulation. When compiling set -DBIG_ENDIAN if your
       computer is big-endian. Set TERM_CONTROL for a crude single character
       (instead of ANSI line-by-line) input. Works on Unix.
v09tc.c same for Turbo C. Has its own term control.

test09.asm and bench09.asm simple test and benchmark progs.

ef09.asm Implementation of E-Forth, a very rudimentary and portable Forth.
      Type WORDS to see what words you have. You can evaluate RPN integer
      expressions, like "12 34 + 5 * . " You can make new words like
      " : SQUARED DUP * ; " etc.




Running on Fedora Core 6
------------------------
2012-06-04

 * BIG_ENDIAN (already used by LINUX itself, changed to CPU_BIG_ENDIAN)
   Now automatically set according to BIG_ENDIAN and BYTE_ORDER
   if existing.

 * If TERM_CONTROL mode is active the keyboard is not really in raw mode -
   keyboard signals are still allowed.

 * A tracefilter based on register values can be placed in the TRACE area to
   get tracing output triggered by special states 
   

a09 Assembler
-------------

Bugfixes:
 * addres modes  a,INDEXREG b,INDEXREG d,INDEXREG now known
    as *legal*!

Extended version:
    http://lennartb.home.xs4all.nl/A09.c
    (see above)

 * options -x and -s produces output in Intel Binary/Srecord format,
   contains the above mentioned bugfixes (but fixed by the original
   author).




v09* Simulator
--------------

### CC register

E F H I N Z V C  Flag
8 7 6 5 4 3 2 1  Bit
| | | | | | | |
| | | | | | | +- $01
| | | | | | +--- $02
| | | | | +----- $04
| | | | +------- $08
| | | +--------- $10
| | +----------- $20
| +------------- $40
+--------------- $80


# differences from real 6809:

ldd #$0fc9
addb #$40
adca #$00

H is set on VCC but not on real 6809, sim6809 does what?

          
### special behavior

    swi2        output character (STDOUT) in register B
    swi3        read character from keyboard into register B
    sync        exit simulator


### start program
v09 BINARY

### start program with tracing output on STDOUT
v09t BINARY

### run program and leave memory dump (64k)

# memory dump in file dump.v09
v09 -d BINARY 



### Bugfixes

* static int index;
  otherwise the global C library function index() is referenced!
  Write access on it leads to a core dump.

 * com with C-operator ~WERT instead 0^WERT ...
   Already fixed in 1994 edition.
 * BIG_ENDIAN is not useable in FLAG because (POSIX?) Unix
   (especially Linux) defines its byte order.
   If BIG_ENDIAN == BYTE_ORDER -> architecture is big endian!
   Changed to CPU_BIG_ENDIAN, which is refering BIG_ENDIAN and
   BYTE_ORDER automatically (if existent).






eForth
------

ef09.asm:

Backspace character changed from 127 to 8.


Memory-Layout:

 0100   At this address the binary is placed to, the Forth entry point
 03C0   USER area start
 4000   Memory TOP


I/O:
    Keyboard input:
     * ^H or BSP deletes character
     * RETURN -> interrupts (long) output

Bugs:
    SEE     ;
    STAR (*)    : * UM* DROP ;  ... wrong,
            : * M* DROP ; ... correct (sign!)

Typical commands:

 Command alway in upper case!!!

WORD        list of defined words of the current vocabulary

BYE     exit Forth (back to shell)
DUMP        hex memory dump 
SEE         HL-word decompiler, corrected:
        * stops at EXIT
        * handles more special primitives (literals, strings,
          variable, constants))
        * handles Direct Threading
        * output line by line with address
.S      shows the content of the parameter stack

count FOR ... NEXT
        replacement for
        hi lo DO ...  I ... LOOP
        hi lo - 1+ FOR ... R@ lo + ... NEXT




Extensions:

    ZEQUAL      0=      Primitive
    PLUS1       1+      Primitive, added
2012-06-07
    ROLL        ROLL        HL, added
    CONST       CONSTANT    HL, added
    doCONST             Primitive, added

2012-06-08
    TWOSTAR     2*      Primtive, added
    TWOSLASH    2/      Primtive, added
    MINUS1      1-      Primtive, added
    SWAPHL      ><      Primtive, added
    STAR256     256*        Primtive, added
    SLASH256    256/        Primtive, added
    CMOVE       CMOVE       Primtive
    FILL        FILL        Primtive
2012-06-09
    ULESS       U<      Primitive
    LESS        <       Primitive
    DO      DO      HL, added
    QDO     ?DO     HL, added
    DODO        (DO)        Primitive, added
    DOQDO       (?DO)       Primitive, added
    LOOP        LOOP        HL, added
    PLOOP       +LOOP       HL, added
    DOLOOP      (LOOP)      Primitive, added
    DOPLOOP     (+LOOP)     Primitive, added
    
2012-06-11
    NEGAT       NEGATE      Primitive, alternative added
    UMSTA       UM*     Primitive, but without MUL
    LSHIFT      LSHIFT      Primitive, added
    RSHIFT      RSHIFT      Primitive, added
2012-06-12
    LEAVE       LEAVE       Primitive, added (fig Forth)
    MDO     -DO     HL, added
    DOMDO       (-DO)       Primitive, added
    I       I       Primitive, added (same as R@)
    CMOVEW      CMOVE       Primitive, other implementation
    STAR        *       korr.: uses M* (instead UM*)
    BLANK       BL      Constant

2012-06-19
    USLASH      U/      Primitive, same as UM/MOD
                    UM/MOD uses USLASH

2012-06-20
    DPLUS       D+      Primitive
    DSUB        D-      HL
    ZERO        0       Constant
    ONE     1       Constant
    TWO     2       Constant
    MONE        -1      Constant
    DOCLIT      doCLIT      Primitive
2012-06-21
    SEE     SEE     extended: handles LIT, CLIT
2012-06-22
    SEE     SEE     extended: handles
                    BRANCH,?BRANCH,?DO,-DO,LOOP,+LOOP,."..."

2012-09-07
    SEE     SEE     ABORT", (DO) added, remarks corrected.

TODO:
 * XXX marked  open points
 * SEE:
  * handling of
    - [COMPILE]
    - DOCONST, DOVAR, DOUSE


TEST:

HEX ok
0 8000 8001 U/ . . FFFE 2 ok
FFFE 8001 U* . . U* ?  ok
FFFE 8001 UM* . . 7FFF FFFE ok
FFFE 8001 UM* 2 0 D+ . . 8000 0 ok

0 8000 7FFF U/ . . FFFF FFFF ok
0 FFFF FFFF U/ . . FFFF FFFF ok
0 FFFE FFFF U/ . . FFFE FFFE ok
FFFF FFFF UM* . . FFFE 1 ok
FFFF FFFE FFFF U/ . . FFFF FFFE ok





Links/References
================


Source:
  http://groups.google.com/group/alt.sources/browse_thread/thread/8bfd60536ec34387/94a7cce3fdc5df67
  Autor: Lennart Benschop  lennart@blade.stack.urc.tue.nl, 
                lennartb@xs4all.nl (Webpage, Subject must start with "Your Homepage"!)

  Newsgroups: alt.sources
  From: lennart@blade.stack.urc.tue.nl (Lennart Benschop)
  Date: 3 Nov 1993 15:21:16 GMT
  Local: Mi 3 Nov. 1993 17:21
  Subject: 6809 assembler and simulator (examples) 2/2


Homepage/Download links of Lennart Benschop:
  http://lennartb.home.xs4all.nl/m6809.html
  http://lennartb.home.xs4all.nl/sbc09.tar.gz
  http://lennartb.home.xs4all.nl/A09.c


Emulator for 6809 written in Python, can run sbc09 ROM:
  https://github.com/jedie/DragonPy/


Newer posting in alt.sources (1994):

  Newsgroups: alt.sources
  From: lenn...@blade.stack.urc.tue.nl (Lennart Benschop)
  Date: 17 May 1994 08:13:25 GMT
  Local: Di 17 Mai 1994 10:13
  Subject: 6809 assembler/simulator (3 of 3)


Referenced by:

  http://foldoc.org/6809
    Reference points to posting with buggy version from 1993.

  http://lennartb.home.xs4all.nl/m6809.html
    BAD LINK: http://www.sandelman.ocunix.on.ca/People/Alan_DeKok/interests/6809.html
    -> http://www.sandelman.ottawa.on.ca/People/Alan_DeKok/interests/
    6809 specific site will be redirected, but does not exist.

    Internet-Archiv:
    https://web.archive.org/web/20070112041235/http://www.striker.ottawa.on.ca/6809/
    2014-05-01: Lennart B. lennartb@xs4all.nl has been informed.

  http://archive.worldofdragon.org/phpBB3/viewtopic.php?f=5&t=4308&start=60#p9750