Compiler Speed Trials

[britlion]

Finally got a quick chance to test this. Yes, -O3 does improve BM7 - but the 0.16 seconds value isn't really fair. -O3 reports that variables are not used and optimizes out all the loops!

I don't remember that optimization. Which code snippet are you using? BM7 above?

Hmm. You yourself said:

if O3 were in use, this program could be reduced to a single NOP, as it does nothing (it does not print on the screen).

All I did was add the line print M(1),k,i,var to the end of BM7 listed above. It prints it once, and it prints it AFTER it's worked out how long it took; so it's not like the print line took 2 seconds to print. It HAS to be that -O3 recognizes the loops and variables aren't being "used" and deletes them from the code. It normally would be quite right to do so, as well. Using them in a print statement, slows the whole thing back down.

Did you also run this modified version on the other compilers? (they might also be doing some optimizations: so just to be sure). Please paste the benchmark code here, or tell me witch one are you using.

If you made some modifications to BM7 and or BM8, please paste them there. Also, the code MUST be the same (e.g. no function calls for any compiler, of function calls for any of them, etc...).

It's really not modified, apart from asking it to print the values of some variables right before it ends. As for running it on other compilers; I didn't - I don't even /have/ all of them handy. I do have hisoft basic, however, and I tested that one myself. I'll get round to remaking it and add in that print statement to be sure, but I don't think it even has something like the -O3 as an optimization loop. It does seem to treat array variables as fast as any other type of variable.

Do the other compilers allow multidimensional arrays of float / string / Integers?

You asked that before, and I'll say again: Almost all of them only allow single dimension number arrays. (Zip compiler won't deal with strings AT ALL!). Hisoft basic does allow multidimensional arrays and string arrays:

HiSoft BASIC supports numeric and string arrays of up to 2 dimensions. Ordinary string variables behave as in BASIC except that they must not exceed in length the amount of space reserved for them at compile time. By default this is 257 bytes (to allow a string of up to 255 characters, plus 2 bytes for the length) but it can be changed by means of the REM : LEN directive.

Quite outside the array issues, I think Hisoft Basic's string handling is vastly less flexible, but far faster than yours. Your strings are always mutable, and of variable sizes. Hisoft uses far less memory efficient fixed string system, not in the heap, which is faster to use. As always, it's memory size and waste vs speed, here. Luckily I've never seen your neat and efficient strings running too slowly, so I think the only "issue" here is array handling. I don't know why your version of the array handling code is the slowest of the tested integer compilers. Is it to do with it handling more variable types, and having to deal with that?

Does it internally know the difference between an array of strings and an array of bytes? Are these different types to the compiler? A fixed size array of numbers is really just a lookup table. Your variable sized string handling (while brilliant in its memory efficiency) makes string arrays much much more awkward to deal with. If you're using the same code to handle arrays of ANYTHING, I can see why hisoft seems to be going faster, here.