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Tinine
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Joined: 30/03/2016
Location: United Kingdom
Posts: 1646

Posted: 04:17pm 18 Aug 2020

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CaptainBoing said interesting. So in the "translated" code, are GOTO lines actual memory addresses?

Yes, here is an example of my quadrature decoder and counter. Unfortunately, I don't have the ASM output but it reads pretty much the same, except for IFs and GOTOs being replaced with some kind of cmp/jmp.

The label and variable names are preserved.
The only oddity in PropBasic is that when testing more than one condition, they need to be on separate lines.

DEVICE P8X32A, XTAL1, PLL16X
FREQ 80_000_000

Chan_A PIN 0 INPUT
Chan_B PIN 1 INPUT
Chan_Z PIN 2 INPUT

Counter VAR LONG = 0
Idx_Monitor VAR LONG = 0
Idx_Count VAR LONG = 0
Count_Error VAR LONG = 0

PROGRAM Start

Start:

'Decide where to start
If Chan_A = 1 And
� �Chan_B = 1 Then
� �Goto A1B1
Endif

If Chan_A = 0 And
� �Chan_B = 0 Then
� �Goto A0B0
Endif

If Chan_A = 1 And
� �Chan_B = 0 Then
� �Goto A1B0
Endif

If Chan_A = 0 And
� �Chan_B = 1 Then
� �Goto A0B1
Endif

'Should keep hopping between these labels unless an illegal
'condition crops up.
�
A1B1:
If Chan_A = 0 Then
� Dec Counter
� Goto A0B1
Elseif Chan_B = 0 Then
� Inc Counter
� Goto A1B0
Endif
Goto A1B1

A0B0:
If Chan_A = 1 Then
� Dec Counter
� Goto A1B0
Elseif Chan_B = 1 Then
� Inc Counter
� Goto A0B1
Endif
Goto A0B0

A1B0:
If Chan_A = 0 Then
� Inc Counter
� Goto A0B0
Elseif Chan_B = 1 Then
� Dec Counter
� Goto A1B1
Endif
Goto A1B0

A0B1:
If Chan_A = 1 Then
� Inc Counter
� Goto A1B1
Elseif Chan_B = 0 Then
� Dec Counter
� Goto A0B0
Endif
Goto A0B1
End

Edited 2020-08-19 02:30 by Tinine

capsikin
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Joined: 30/06/2020
Location: Australia
Posts: 341

Posted: 02:11am 19 Aug 2020

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CaptainBoing said a little code. Times in mS (natch)

I tried to avoid timing anything but the switch and made the workload as identical as I could. Select is around twice as fast as a On x GoSub but it's all relative and tweakable

I modified the program for a CMM2 to try and do some comparisons, but it seems like the speed depends on how many lines come before the code (at least for goto). So I modified it more to show that.

I thought I saw someone talking about some basics searching through the program lines to find the jump target, maybe it's doing that.

It took about 1000 ms with the GOTO and a bunch of statement lines before the code, faster without the goto or without the extra lines. (maybe reduce the number of loops on a slower processor)

Dim Integer n,t,tt

print:print

tt=0
tt=0
tt=0
tt=0
tt=0
tt=0
tt=0
tt=0
tt=0
tt=0
tt=0
tt=0
tt=0
tt=0
tt=0
tt=0
tt=0
tt=0
tt=0
tt=0
tt=0
tt=0
tt=0
tt=0

'tt=0
'tt=0
'tt=0
'tt=0
'tt=0
'some redundant lines to test if it slows things down loater.

timer=0
for n=1 to 100000

'comment out goto to just test the for loop
goto 10
10
Next

t=timer

?t,
?"with just for loop or with numbers GoTo":?

print "if goto command is used, speed depends on how many statement lines I add before it."

print "if goto command is not used, speed stays the same (for loop not affected by earlier lines)"

print "goto not affected by any lines after, or comment lines before."
end

tt=0
tt=0
tt=0
tt=0
tt=0
tt=0
tt=0
tt=0
tt=0
tt=0
tt=0
tt=0
tt=0
tt=0
tt=0
tt=0
tt=0
tt=0
tt=0
tt=0
tt=0
tt=0
tt=0
tt=0

capsikin
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Joined: 30/06/2020
Location: Australia
Posts: 341

Posted: 02:50am 19 Aug 2020

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Tinine said Yes! The moral of the story is don't write spaghetti code!

Don't blame GOTO.

I kind of agree, and for a two line loop like

10 PRINT "Hello World!"
20 GOTO 10

I don't think it's unclear at all,
but for larger structures, even just 4 or 5 lines, the indentation conventions make standard structures easier to read.
(in general - not saying they work well for everything).

That said the indentation conventions don't highlight an EXIT DO or EXIT SUB like they do with the start and end of the DO or SUB structure - I wonder if there's a good way to do this. And you can indent any GOTO code if you can work out a clear way to do it (loops might not be too hard, but you don't need GOTO for making loops).

Also if you use labels rather than line numbers, GOTO doesn't show you if you're jumping forward or backwards.
Edited 2020-08-19 12:51 by capsikin

hitsware2

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Joined: 03/08/2019
Location: United States
Posts: 719

Posted: 04:14pm 19 Aug 2020

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> Also if you use labels rather than line numbers,
> GOTO doesn't show you if you're jumping forward
> or backwards.

FWIW : Having line numbers doesn't mean they are sequential .

my site

CaptainBoing

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Joined: 07/09/2016
Location: United Kingdom
Posts: 2170

Posted: 04:03pm 20 Aug 2020

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Tinine said
Makes no real difference, actually but it just makes me feel better to know that I have greater efficiency. �

Here's another one to scratch the efficiency pedant itch for you then:

>
Clear
Dim Integer a,t

> timer=0:for a=1 to 1000000:next a:t=timer:print t
30168
> timer=0:for a=1 to 1000000:next:t=timer:print t
23828
>

Drop the variable off the Next and shave some mS. The last loop executes in only 79% of the time (aatch, that is quite a bit!)

Like you said, Makes no real difference but, Ooh, yeah! feels good!

Edited 2020-08-21 03:03 by CaptainBoing

Poppy

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Joined: 25/07/2019
Location: Germany
Posts: 486

Posted: 07:40pm 20 Aug 2020

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CaptainBoing said Ooh, yeah! feels good!

Isn�t this actually all about BASIC?

Andre ... such a GURU?

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