Entity Mark Butcher spoke thus:
> If I'm understanding you correctly, I think the answer is no. Are you
> asking if MathWallah will execute a program for an HP-49? I'm afraid
> not.
http://approtec.org/mathwallah/
I see, it is not a Forth emulator although it does use RPN and a stack.
> I have an HP-48, by the way. A major problem for me with the
> Reverse Polish Language is its readability. It's very hard to figure
> out what the program is doing. If you can convert the program to AS,
> then MathWallah could run it from one of its custom keys.
Well, I'm using X48 which looks like
http://Spectrumology.com/Time/Time.html#Hp48
I don't like algebraic expressions as they are slow and too symbolic.
I will tell you, writing Forth routines can be a real challenge because of
the interaction of what the stack is doing with the program. In worst
cases
it's helpful to lay squares of paper with actual values out on a table and
pretend it's the stack. A Forth emulator to do this task on the Mac would
be
a great tool tool.
> But I'm intrigued. How did you get the HP-49 program onto your mac? I
> thought HP didn't support macs any more.
They don't and I don't think they ever did. But I transferred its memory
to
a PC then to my Mac as text files.
> Also, I'm not familiar with
> Forth. When you say 'straight out of an HP-49', do you mean Reverse
> Polish Language (RPL)?
Yes, I suppose so. Actually Forth is nothing more than an extension of
your
stack-based arithmetic.
On your "Stack" keyboard you already have DUP(licate) SWAP ROLL ROLLD(own)
DROP(1 object) DROPN (Clear N Stack objects) etc.
Now imagine commands like :
PICKN duplicate N stack object to the bottom
DUPN duplicate N objects sequentially to the bottom
SIZE puts number of objects in a list on the stack
DO...UNTIL...END should be obvious
OVER duplicate line 2
ROT rotate 3 lines up (line 3 will be on bottom)
EVAL evaluate (execute as a program, even a list)
DROP2 delete bottom 2 objects
-> var assign object to this variable
« » delimits a program object
{1,2,3...} delimits a data object
Hope that all makes sense, obviously I'm a Forthhead.
-- Gnarlie
http://www.PowerMops.com/
PowerMops: Forth Programming Language for Macintosh
> On Jun 14, 2004, at 3:30 PM, Gnarlodious wrote:
>
>> Mark:
>> Rather than flounder around trying to figure it out for myself, will
>> you tell me if this is the sort of thing Mathwallah can do? It is
>> Forth straight out of an HP-49.
>>
>> Thanks, Rachel.
>>
>>
>> CHOP:
>>
>> Stack in:
>>
>> 2: .66666
>> 1: {
>> 1,1.00148787245,1.00154083222,1.00185529972,1.00286558276,1.00502512563
>> }
>>
>>
>>
>> << DUP SIZE SWAP OBJ-> DUP 3 + ROLL UVAL SWAP { 1 36 / 22 *
>> DUP 1 - 3 PICK > SWAP 3 PICK < - } -> g
>> <<
>> DO SWAP FP g EVAL + OVER 2 + ROLL * g EVAL SWAP DUP2 XOR
>> * DUP NOT 22 * ROT ABS SIGN - DUP ROT + OVER NOT 36 * ROT SIGN + * DUP
>> DUP SIGN + IP 3 PICK 3 + ROLLD
>> UNTIL
>> SWAP 1 - DUP NOT
>> END
>> >> DROP2
>> >>
>>
>>
>> Stack out:
>>
>> n: most significant element
>> ~
>> 2: least significant element
>> 1: number of elements on stack
>>
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