First thing that spring to mind is an internal EEPROM based lookup table. This will save a lot of IF-THEN and code space.
Or throw all your data in MiscEl or Excel and see if you can extract an accurate enough formula from it (Curve fit).
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Re: A more program space efficient way of doing ta whole heap of IFs????
First thing that spring to mind is an internal EEPROM based lookup table. This will save a lot of IF-THEN and code space.
Or throw all your data in MiscEl or Excel and see if you can extract an accurate enough formula from it (Curve fit).
Steve
It's not a bug, it's a random feature.
There's no problem, only learning opportunities.
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Re: A more program space efficient way of doing ta whole heap of IFs????
Use ELSEIF.
The second test in each line is not needed, because the previous test already checked that condition. And having multiple conditions in an IF line involves temporary system variables to save the intermediate results.
The code in post#1 compiled to 559 words.
This one is 189 words.
PBP 2.60 required, but the same thing can be done without 2.60 and elseif.Code:if supply_in>= 253 then max_duty = 154 ELSEIF supply_in> 250 then max_duty = 155 ELSEIF supply_in> 248 then max_duty = 156 ELSEIF supply_in> 245 then max_duty = 157 ELSEIF supply_in> 240 then max_duty = 159 ELSEIF supply_in> 237 then max_duty = 160 ELSEIF supply_in> 234 then max_duty = 161 ELSEIF supply_in> 231 then max_duty = 163 ELSEIF supply_in> 229 then max_duty = 165 ELSEIF supply_in> 226 then max_duty = 167 ELSEIF supply_in> 223 then max_duty = 169 ELSEIF supply_in> 220 then max_duty = 172 ELSEIF supply_in> 218 then max_duty = 175 ELSEIF supply_in> 215 then max_duty = 179 ELSEIF supply_in> 212 then max_duty = 181 ELSEIF supply_in> 210 then max_duty = 182 ELSEIF supply_in> 207 then max_duty = 184 ELSEIF supply_in> 204 then max_duty = 188 ELSEIF supply_in> 201 then max_duty = 191 ELSEIF supply_in> 199 then max_duty = 195 ELSEIF supply_in> 196 then max_duty = 214 ELSEIF supply_in> 193 then max_duty = 238 ELSEIF supply_in> 187 then max_duty = 251 ELSE max_duty = 255 ENDIF
DT
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Re: A more program space efficient way of doing ta whole heap of IFs????
Here's another way.
Oddly enough, it's 191 words.
Code:supply_in VAR BYTE max_duty VAR BYTE ItemNo VAR BYTE ' LOOKDOWN2 supply_in, >[252,250,248,245,240,237,234,231,229,226,223,220,218,215,212,210,207,204,201,199,196,193,187,0],ItemNo LOOKUP ItemNo,[154,155,156,157,159,160,161,163,165,167,169,172,175,179,181,182,184,188,191,195,214,238,251,255],max_duty
DT
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Re: A more program space efficient way of doing ta whole heap of IFs????
OK, so let's go with Steve's idea and put it in EEPROM.
88 words.
I haven't tested it, but it looks right.Code:supply_in VAR BYTE max_duty VAR BYTE ItemNo VAR BYTE Temp VAR BYTE ' supply_Max DATA 252,250,248,245,240,237,234,231,229,226,223,220,218,215,212,210,207,204,201,199,196,193,187,0 Set_duty DATA 154,155,156,157,159,160,161,163,165,167,169,172,175,179,181,182,184,188,191,195,214,238,251,255 ' FOR ItemNo = 0 TO (Set_duty - supply_Max) READ (supply_max + ItemNo), Temp IF supply_in > Temp THEN READ (Set_duty + ItemNo), Temp max_duty = Temp EXIT ENDIF NEXT ItemNo
Check my work.
DT
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Re: A more program space efficient way of doing ta whole heap of IFs????
Wow....what can I say Darrel....you lost me after the elseif post, but I'm gonna read it again & again until it sinks in!
(also thank you steve ....all great stuff)
Edit: Even just rolling with the ELSEIF melarkey ...my program now compiles at 1643 words ...it was maxing out before (greater than 2048 words), so even if I never get to understand the EEPROM method (& the initial indications aren't favourable, lol!) then nevertheless you've saved the day!
Last edited by HankMcSpank; - 27th May 2011 at 12:49.
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Re: A more program space efficient way of doing ta whole heap of IFs????
PICs have 2 areas of memory: codespace, for your program, and eeprom, you use DATA to store data and READ to get at it (you can also WRITE to it during program execution).
Eeprom is a simple way to store tables and then use For loops to scan through them later. Three common uses; character definitions for LCDs, conversion tables and saving PIN numbers.
I think Melanie has a thread somewhere on how to use some of that eeprom area for codespace.
Last edited by Demon; - 27th May 2011 at 13:26.
My Creality Ender 3 S1 Plus is a giant paperweight that can't even be used as a boat anchor, cause I'd be fined for polluting our waterways with electronic devices.
Not as dumb as yesterday, but stupider than tomorrow!
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Re: A more program space efficient way of doing ta whole heap of IFs????
Thanks Robert (a cool name ;-) )...while I'm fairly clued up on how to get the PIC to work now (as well as being reasonably savvy on the electronics /interfacing aspect), the darned pesky coding world is still totally flat in my eyes!! (this is frustrating as I have a head brimmed with ideas...but no quick way to get them out of my fingertips & into a PIC)Originally Posted by Demon
I'll have to take a night out to get the hang of using EEPROM so I'll have a search for any related threads outlining how to get started with them.
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Re: A more program space efficient way of doing ta whole heap of IFs????
Option 2:
Could also shave it a lil more, but use a single and larger Lookup...
couldn't be more simple I guessCode:DATA @188, ....all duty result from 188........256 bytes available btw . . . . if supply_in< 188 then max_duty = 255 else READ Supply_in, Max_duty endif
I know you love challenge Darrel :P
Steve
It's not a bug, it's a random feature.
There's no problem, only learning opportunities.
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Re: A more program space efficient way of doing ta whole heap of IFs????
I originally shyed away from using suggestion, on account the initial idea provided rescued me back sufficient space, but alas, things have just got too tight, so I've just tried this latter suggestion...it worked first time & has rescued me back a good bit of space (room to breathe again!)
I'll admit I don't totally understand what's going one (other than we're storing stuff in EEPROM, then cleverly marrying it up), I'll addess my inner "huh?" demons & work this out soon, but for now I'm just chuffed the enigma works...as a bonus it's far easier for me to mate the values (the formatting on here clouds it, but it's as clear as day in reality)
Many thanks.
Last edited by HankMcSpank; - 19th June 2011 at 12:51.
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Re: A more program space efficient way of doing ta whole heap of IFs????
Darrel,
Let me ask a very dumb question here about your ELSEIF program. Lets say for example that variable supply_in= 251. Does the program exits the IF..ENDIF block after it encounters the lines
ELSEIF supply_in> 250 then
max_duty = 155
or does it keep going through the rest of the ELSEIF lines in the IF..ENDIF block? I checked the manual but I didn't see the answer to my question.
Thanks,
Robert
"No one is completely worthless. They can always serve as a bad example."
Anonymous
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Coding Examples
Darrel,
I have to say your coding examples are nothing short of excellent.
That is one place that I think the PBP manual could be improved. I came over from the basic stamp, their manual was quite good with examples.
The hardest thing for me to do is to go from a technical description of a given PBP command to a real world working piece of code. Whereas, once I see how to correctly use a given PBP statement, then I can usually write my way through my own code. Where I usually have trouble is with the syntax and good examples are invaluable. There seems to be a lot of wasted blank paper in the manual that could be filled up with more syntax examples.
If MElabs could produce a webpage where a person could goto and enter any given PBP statement and see a few (several) examples of good code, it would help the newbie greatly. I know there are a few of those over at MElabs but there could be more.
Please pass this along to the MElabs people.
You are a real asset to the group... and I look forward to future releases of PBP that might?? include some of your excellent coding work implemented as new PBP statements.
Last edited by Heckler; - 27th May 2011 at 15:01.
Dwight
These PIC's are like intricate puzzles just waiting for one to discover their secrets and MASTER their capabilities.
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Re: A more program space efficient way of doing ta whole heap of IFs????
If there is a mathematical relationship between supply_in and max_duty, it might be more efficient to just compute max_duty as supply_in varies.
Also, if the relationship could be refined to eliminate the max _duty granular discontinuities (i.e. if it can vary in steps of 1 or any constant step), a loop might be better.
Last edited by dhouston; - 27th May 2011 at 16:49.
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Re: A more program space efficient way of doing ta whole heap of IFs????
I'd considered that, but alas the supply_in vs the max_duty required is all over the shop....hence the multiple ifs!
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Re: Coding Examples
This forum, PBPGroup, Rentron.com & Melabs website are full of handy code example, take a pick, modify them, try to make them better.
To me the PBP book is perfect. It explain what a specific command do. Just build a test program around it and you're all set. There's by far worst reference book... check MPASM assembler, most (see any) API/DLL reference... list is long
Programming... It's like everything, practice makes "perfect", the more you do, the easier it gets. Call it experience if you like. It take months, years, decade... it's a never ending learning process... welcome on the dark side
Steve
It's not a bug, it's a random feature.
There's no problem, only learning opportunities.
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Re: A more program space efficient way of doing ta whole heap of IFs????
That one''s easy (programmer by trade), it exits the nested IFs after assigning 155.Darrel,
Let me ask a very dumb question here about your ELSEIF program
ELSEIF supply_in> 250 then
max_duty = 155
...
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Re: A more program space efficient way of doing ta whole heap of IFs????
Ooh, I see. Thank you Robert.
"No one is completely worthless. They can always serve as a bad example."
Anonymous
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Re: A more program space efficient way of doing ta whole heap of IFs????
When in doubt, use debug feature.
If you don't have a debug feature (using Wordpad instead of an IDE), then make one up. Just put in a bunch of LEDs on empty ports, and then make them blink different ways in different places in your code.
Or even better, get the easiest LCD on the market, the HD44780, and send debug messages (abbreviated syntax, just for example):
We do something similar as mainframe programmers; it's called using DISPLAY statements. There is no limit to what you can use as a debug feature. If it works for you, then it's perfect.Code:LCDOUT "Program start", var1, var2 Label_A: LCDOUT "Label A", var1, var2 Program logic... IF var1 < var2 then goto Label_A Label_B: LCDOUT "Label B", var1, var2 More program logic... IF var1 < var2 then goto Label_B LCDOUT "Program end", var1, var2
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