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Groups > comp.sys.acorn.programmer > #440

Re: Font_DecodeMenu

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In article <mpro.lmuj8p02zu8sw01cg.news@stevefryatt.org.uk>,
   Steve Fryatt <news@stevefryatt.org.uk> wrote:
> 1. Preferring, for reasons of non-hack to do something like

I think saying it's a 'hack' to use a deliberate, documented feature of the
BASIC SYS statement is probably pushing it.

Some people use OS_IntOn rather than XOS_GenerateError. I'm not sure which
is fastest or best. There's only one way to find out. Fight!

In my quick test, the OS_IntOn method was 30% faster if we call the SWI by
name, whereas when calling the SWI by number, OS_IntOn was only 4% faster.
This seems to show that calling SWIs by name is slow, especially the X form
of SWIs and BASIC having to interpret a longer SWI name string doesn't help.

>   DEF FNread_string(string%)
>   LOCAL string$
>
>   string$ = ""

The above is not required; BASIC initialises local variables for you.

>   WHILE ?string% <> 0

Why would you ever bother with the "<> 0" part? It's as pointless as LET.

>     string$ += CHR$(?string%)
>     string% += 1
>   ENDWHILE
>   =string$

Finally, I'd use ptr% rather than string% to make it easier to
read/understand. Well, I would if I didn't use XOS_GenerateError in the
first place.

Ta,

Steve

-- 
Steve Revill @ Home
Note: All opinions expressed herein are my own.

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Thread

Font_DecodeMenu Paul Sprangers <Paul@sprie.nl> - 2011-06-14 12:24 +0200
  Re: Font_DecodeMenu Rick Murray <heyrickmail-usenet@yahoo.co.uk> - 2011-06-14 15:54 +0200
    Re: Font_DecodeMenu Martin Wuerthner <spamtrap@mw-software.com> - 2011-06-14 20:52 +0200
    Re: Font_DecodeMenu Paul Sprangers <Paul@sprie.nl> - 2011-06-14 23:56 +0200
  Re: Font_DecodeMenu Steve Fryatt <news@stevefryatt.org.uk> - 2011-06-14 22:43 +0100
    Re: Font_DecodeMenu Rick Murray <heyrickmail-usenet@yahoo.co.uk> - 2011-06-15 06:50 +0200
      Re: Font_DecodeMenu Martin Wuerthner <spamtrap@mw-software.com> - 2011-06-15 13:18 +0200
        Re: Font_DecodeMenu Rick Murray <heyrickmail-usenet@yahoo.co.uk> - 2011-06-15 15:38 +0200
          Re: Font_DecodeMenu Steve Drain <steve@kappa.me.uk> - 2011-06-15 17:20 +0100
      Re: Font_DecodeMenu Steve Fryatt <news@stevefryatt.org.uk> - 2011-06-15 20:24 +0100
        Re: Font_DecodeMenu "Ste (news)" <steve@revi11.plus.com> - 2011-06-15 21:19 +0100
          Re: Font_DecodeMenu Steve Fryatt <news@stevefryatt.org.uk> - 2011-06-15 22:14 +0100
            Re: Font_DecodeMenu "Ste (news)" <steve@revi11.plus.com> - 2011-06-16 14:35 +0100
              Re: Font_DecodeMenu Rick Murray <heyrickmail-usenet@yahoo.co.uk> - 2011-06-16 18:10 +0200
          Re: Font_DecodeMenu Rick Murray <heyrickmail-usenet@yahoo.co.uk> - 2011-06-16 18:04 +0200
            Re: Font_DecodeMenu Rick Murray <heyrickmail-usenet@yahoo.co.uk> - 2011-06-16 18:51 +0200
            Re: Font_DecodeMenu "Ste (news)" <steve@revi11.plus.com> - 2011-06-16 18:12 +0100
              Re: Font_DecodeMenu John Tytgat <this@is.invalid> - 2011-06-21 19:19 +0200
                Re: Font_DecodeMenu Rick Murray <heyrickmail-usenet@yahoo.co.uk> - 2011-06-22 19:18 +0200
                Re: Font_DecodeMenu "Ste (news)" <steve@revi11.plus.com> - 2011-06-25 17:53 +0100
                Re: Font_DecodeMenu John Tytgat <this@is.invalid> - 2011-06-27 13:06 +0200
        Re: Font_DecodeMenu Alan Wrigley <spamhater@keepyourfilthyspamtoyourself.co.uk> - 2011-06-15 22:13 +0100

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