[SLOF] [PATCH] Fix output word

[Laurent Vivier]

On 27/09/2017 09:25, Thomas Huth wrote:
> On 26.09.2017 13:28, Laurent Vivier wrote:
>> We can select the console output, but it does not really work
>>
>> Implement term-io-emit, as we have term-io-key to really
>> send characters to the output selected by stdout.
>>
>> Signed-off-by: Laurent Vivier <lvivier at redhat.com>
>> ---
>>  slof/fs/term-io.fs | 14 ++++++++++++++
>>  1 file changed, 14 insertions(+)
>>
>> diff --git a/slof/fs/term-io.fs b/slof/fs/term-io.fs
>> index 52ce12a..a0b0f4b 100644
>> --- a/slof/fs/term-io.fs
>> +++ b/slof/fs/term-io.fs
>> @@ -40,6 +40,20 @@
>>  
>>  1 BUFFER: (term-io-char-buf)
>>  
>> +: term-io-emit ( char -- )
>> +    s" stdout" get-chosen IF
>> +        decode-int nip nip dup 0= IF 0 EXIT THEN
>> +	swap (term-io-char-buf) c!
>> +	>r (term-io-char-buf) 1 s" write" r@ $call-method
>> +	drop
>> +	r> drop
>> +    ELSE
>> +        [ ' emit behavior compile, ]
>> +    THEN
>> +;
> 
> While this is basically the right direction, I've got three concerns /
> remarks:
> 
> 1) Please don't use TABs in Forth code (see Coding Style in README)

Yes, sorry, I've seen that after having sent the patch.

> 
> 2) Have you checked whether it also works with VGA screens? The code in
>    slof/fs/display.fs ticks to EMIT again ... it looks like it should
>    work, but better test it first...

In fact, it doesn't work... The serial console is mirrored to the VGA
display, and when we try to switch to the second serial console, only
the input moves (output stays on the first console and VGA).

> 
> 3) Speed ... This rather code is called for every character that we
>    print out. While it likely does not really matter for input, the
>    output of text was always a rather critical thing in SLOF. Could
>    you please do some speed measurements first? Something like:
> 
>    milliseconds 2000 0 do 41 emit loop milliseconds swap - cr .d cr
> 
>    ... and then compare the values before and after your change.

Without:

  797 796 807

With:

  4772 4710 4782

So it's 6 times slower... what can we do for that?

Thanks,
Laurent