Which is faster?

[SFSxOI]

Which one of these methods is faster? Both accomplish the same thing:

Code: Select all

rslt_test_a.l = Random(256) 
test_ret_a$ = Hex(rslt_test_a)

or......

test_ret_a$ = Hex(Random(256))

[ts-soft]

I think, is the same, but the first one is more readable

[berryoxide]

Look at the ASM output and figure out if there are different calls used and count the CPU cycles together if you need
In practice both do the same thing maybe even equally fast, but in theory depending on the compiler and how it parses the source code, there can be a slight 0.1% speed difference that doesn't really count in overall performance...

[Heathen]

#1

Code: Select all

; rslt_test_a.l = Random(256)
  MOV    eax,256
  CALL   PB_Random
  MOV    dword [v_rslt_test_a],eax
; test_ret_a$ = Hex(rslt_test_a)
  MOV    eax,[_PB_StringBasePosition]
  PUSH   eax
  PUSH   eax
  PUSH   dword [v_rslt_test_a]
  CALL  _PB_Hex@8
  LEA    ecx,[v_test_ret_a$]
  POP    edx
  CALL   SYS_AllocateString

#2 (should be slightly faster)

Code: Select all

; test_ret_a$ = Hex(Random(256))
  MOV    eax,[_PB_StringBasePosition]
  PUSH   eax
  PUSH   eax
  MOV    eax,256
  CALL   PB_Random
  PUSH   eax
  CALL  _PB_Hex@8
  LEA    ecx,[v_test_ret_a$]
  POP    edx
  CALL   SYS_AllocateString

[sampb]

Hi all,

How to get "ASM output"?

Thanks in advance

[Psychophanta]

In opposit to ts-soft, sorry but i think the 2nd one is much more readable

Hi all,

How to get "ASM output"?

Thanks in advance

look at the manual, at the GetDisASMString() function

[Trond]

Hi all,

How to get "ASM output"?

Thanks in advance

pbcompiler.exe yourfile.pb /COMMENTED

[Kaeru Gaman]

the performance is not the only thing in question.
normally, you would use a random number not only for output, but also for calculations.
the first version already holds the value in a variable, the second one only provides the string.

[SFSxOI]

well, after checking it out some more and considering the input from you folks i've decided to go with the second one and kind of combine all your words of wisdom into one solution. I only really need the string, it helps 'neaten' the procedure it lives in by reducing clutter in the procedure and makes the overall procedure more readable, and the time differences are not that great between the two enough to really matter. Thanks for your input folks

[pdwyer]

If this is such a tight loop that a difference like this is being sought for perf reasons, you many want to consider a faster random() proc. Not criticising PB's but it's chosen as a good balance of speed and randomness. Just like you wouldn't use it in a security application perhaps you should replace it for a hi-perf one. It's a black box after all.

Depends on what you need

[SFSxOI]

"hi-perf" as in what type of high performance procedure you talking about?

[pdwyer]

There are many different PRNG's, some optimised for randomness benchmarks, some for speed, some for security. Others for all round

http://en.wikipedia.org/wiki/PRNG

I believe a couple are implemented in the tips section already.

Sounds like, from the question, that you are after one optimised for speed.