Old MoveJOH_PAS_3 move memory more fast , even copymemory or
zeromemory?
lazarus / 34-Windows

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d2010 · 2025-04-24 15:59

Hello.
In few cases, I move memory (always move-memory fix 32characters fix
exactly one point of project.lpr).
In that case, other user, say Must I replace copymemory with Move_i32,
but
the program-developer must be 100% sure the size=32characters.
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i Procedure
Move_i32(const ASource; var ADest; ACount: Integer);asm  mov ecx,
[eax]  mov [edx], ecx             {4}  mov ecx, [eax + 4]  mov [edx +
4], ecx         {8}  mov ecx, [eax + 8]  mov [edx + 8], ecx        
{12}  mov ecx, [eax + 12]  mov [edx + 12], ecx        {14}  mov ecx,
[eax + 16]  mov [edx + 16], ecx        {16}  mov ecx, [eax + 20]  mov
[edx + 20], ecx        {24}  mov ecx, [eax + 24]  mov [edx + 24], ecx
      {24}  mov ecx, [eax + 28]  mov [edx + 28], ecx      
 {28}end; Example1: 

Code: [Select]Procedure Good10Solutionl
Var cnt:integer;
Begin //more fast
   for  cnt:= 1 to (01 shl 20) do Move_i32(srce,dest,32);
End;

Procedure Slow10Solution;
Var cnt:integer;
Begin
   for  cnt:= 1 to (01 shl 20) do copymemory(dest,srce,32);
End;
C:Q1=Can I use this trick? in general it is very good for
CrossPlatforms = Android, Linux, BeOs..?
C:Q2=It is good-solution for Move_i04,Move_i06? at means I replace
copymemory with
Procedure Move_i04(const ASource; var ADest; ACount: Integer);
Procedure Move_i08(const ASource; var ADest; ACount: Integer);
Procedure Move_f08(src:pchar;ADest:pchar; ACount: Integer);
Thank.

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BrunoK · 2025-04-24 17:11

In a few cases, I move the memory (allal televisions the fixed memory
32 characters to fix a project point.lpr).
In this case, a wearer, pause Jeis repackaging the copy memory with
Move-i32, but
the program-develling which is 100% secure in size of 32 characters.

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i
Good10Solutionl ProcedureVar knt: whole meter;Start  //more quick 
 for cnt:= 1 before (01cl 20) do Move_i32(srce, dest,32);The
End; Slow10SolutionProcedure;Var knt: whole meter;Start   for n:= 1
before (01 wast 20) make a copy(dest,srce,32);The End;

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marcov · 2025-04-24 20:11

These are old D7 tricks, but the FPC move uses sse2 if available, and
afaik so does D2006+

Did you test this is necessary at all?

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Thaddy · 2025-04-25 05:47

Better not use that trick:
The compiler is often more efficient and your code is not portable.
It was OK about 20 years ago, though.