BBC BASIC for the PDP-11 - Changes list
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08-Nov-2009
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Commands:
PROC(addr%), FN(addr%), string buffer is at ^@%-256.

05-Nov-2009
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Commands:
RESTORE [DATA|ERROR], LOCAL [DATA|ERROR], ENDPROC, =, drop and restore locals.

25-Oct-2009
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Word pushed onto empty stack when executing so when structure terminators
check 2(sp) for matching structure opener, not reading past end of allocated
memory. Program structures push structure token on stack, not return address. 

09-Mar-2009
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LOAD/CHAIN can load and tokenise text file. Tokeniser sped up with offsets
to each initial letter, line numbers tokenised correctly, LineFind written
to search for program line for GOTO/GOSUB/RETURN and line editing.

03-Mar-2009
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LOAD file$,addr, 31-bit decimal numbers working, times10 subroutine working.

27-Feb-2009
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HostIO:
Hurrah! Finally managed to get through the stty()/ioctrl() madness on
real UNIX. Using stty() causes no end of problems when switching to and
from raw/cooked/echo mode, needed to output something to kick the output
stream before things like quit would work. Now using ioctrl(), but that's
not available on v6. Will have to work aroud this.
Quit now restores tty characters as well as settings. SIGQUIT calls Quit.
SIGINT terminates read() so Escape works in OSRDCH and Input. Character
delays and crmod turned off in tty. OSARGS 0,0 returns 24 for UNIXFS.

25-Feb-2009
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HostIO:
Bashing away at getting iotty and SIGINT handling working on real UNIX.

Functions:
Calls to MOS entries working, registers returned right way around from USR.

Evaluate:
^<id> implemented.

Commands:
Variable assignment mostly written.

Variables:
Static variables and indirection implemented.

18-Jan-2009
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Execute:
\ line continuation character implemented

04-Sep-2008
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Evaluate:
&oXXX octal numbers, %xxxx binary numbers

Functions:
STRING$, STR$, LEFT$, RIGHT$, VAL, EVAL, LineNum, USR, CALL, RND

Commands:
LIST, REPEAT/UNTIL, GOTO/GOSUB/RETURN, RESTORE, IF, TRACE

Tokens:
Detokeniser

31-Aug-2008
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Interface:
SOUND ON|OFF, =TIME$ checks for null return, GET$#chn, BPUT#chn,s$
GCOL c, COLOUR l,[p|r,g,b], PLOT x,y, SOUND, ENVELOPE

Commands:
NumberToString does integer hex and decimal

Functions:
Added binary functions to dispatch table, OR, EOR, AND, +, -, *, /, DIV
Full general integer arithmetic now fully implemented

Evaluate:
Full seven-level recusive evaluator written, hex numbers, double quotes

Stack:
Push and pop items from BASIC stack, prechecks non-string arguments
before dispatching to function code

Tokens:
Added 'Missing ' token to use in error messages.

12-Feb-2008
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HostIO:
IO_Init
IO calls vector to subroutines
IO_Init sets tty to raw/noecho
quit sets tty to noraw/echo
word0 does delete with vdu 8,32,8
RDCH/WRCH use direct TRAP calls
CLI checks for *Quit command

GeneralIO:
printR0 processes COUNT
IO_ReadLine calls OSWORD 0
IO_Escape generates error if escape state

SysVars:
Added SV_Escape
Added IO calls vector table
Vector table has default UNIX_* entries

Commands:
Command table uses dest-$
Command table is 80-FF
STOP temp. used for QUIT
PRINT uses test code
ERROR, STOP, NEW, LIST done
PAGE=, LOMEM=, HIMEM= done

28-Jan-2008
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Startup:
Doesn't clear sysvars - done by loader

Execute:
Error handler, ON ERROR dispatch
REPORT, RUN, CHAIN

Tokens:
Uses Acorn-style token table
Tokeniser written - needs optimising

Interface:
CLS, CLG, COLOUR, MODE, =MODE, =POS, =VPOS, OSCLI, DRAW, MOVE, PLOT, GCOL
VDU gives 'missing comma'
close, bput, ptr, ext, load, loadprogram
save, =ptr, =ext, =bget, =eof,
oscli, =oscli, adval

Evaluate:
EvalXXX check for char, then evaluate integer
temp. simple integer and string evaluation
   
Functions:
=<program functions>
 
Commands:
PRINT works fully, number conversion not yet implemented