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Topic: Parallel Assembly (Read 1238 times) |
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Ric
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Re: Parallel Assembly
« Reply #8 on: Apr 18th, 2017, 09:42am » |
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Thanks Richard,
It is questions like "what are ^I% and H%" and what do they need to be set to.
I assume start% is the start address of the assembly to be created as a thread?
Can I simply exchange start% for the address label?
They may be simple questions, but without answers I am flummoxed.
Regards Ric
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Richard Russell
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Re: Parallel Assembly
« Reply #9 on: Apr 18th, 2017, 1:21pm » |
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on Apr 18th, 2017, 09:42am, Ric wrote:| It is questions like "what are ^I% and H%" and what do they need to be set to. |
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It's all explained in great detail at the MSDN page to which I linked (or in the case of BBCSDL at the SDL Wiki). You cannot expect to call Windows API functions without referring to their descriptions at MSDN. It would be wasteful duplication (and probably a violation of Copyright) for me to reproduce here what is written there, and valuable links to other MSDN references might be lost.
Quote:| They may be simple questions, but without answers I am flummoxed. |
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Every programming language that provides support for calling Windows API functions (and functions in other DLLs), whether it be by BBC BASIC's SYS statement, or Liberty BASIC's CALLDLL statement, or Visual BASIC's __stdcall declaration, requires the programmer to consult MSDN (etc.) to discover how the function is called, what its parameters are and what value (if any) it returns.
Richard.
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Ric
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Re: Parallel Assembly
« Reply #10 on: Apr 19th, 2017, 4:18pm » |
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I have now managed to create threads successfully, using help from MSDN(etc...) and a post by Michael Hutton. So many thanks, now I can see clearly, you were right, it is simple😊 There is just one thing I can not figure, why is the last parameter X TO y and not just an address/variable?
Regards Ric
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Ric
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Re: Parallel Assembly
« Reply #11 on: Apr 28th, 2017, 8:00pm » |
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Richard
It has taken a while but I now understand that it is not x to y after the last comma, but the first six parameters to thread handle. I have created both BASIC and ASM versions of "CreateThread" and in BASIC my laptop will allow 5 threads, but appears to only run two at a time (is this normal?), but in ASM when I try to create more than one thread the program crashes, is this because I can only create two threads at the same time and the current ASM code counts as one of them? Or am I missing something?
The code to create the codes in ASM is
Code: push 0 push 0 push 0 push start push 1024 push 0 CALL "CreateThread" mov [thread1], eax
Regards Ric
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Richard Russell
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Re: Parallel Assembly
« Reply #12 on: Apr 28th, 2017, 9:21pm » |
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on Apr 28th, 2017, 8:00pm, Ric wrote:| when I try to create more than one thread the program crashes, is this because I can only create two threads at the same time and the current ASM code counts as one of them? |
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You ought to be able to run hundreds of threads (at least!). To get a feel for the number of threads typically running on your PC, start Task Manager, select the 'Details' tab and then right-click on any of the column headings. One of the options you will see is 'Select Columns' - click on that and then tick the 'Threads' checkbox. Now you will see how many threads each process is running - the total is likely to be several hundred!
So if you are finding that you cannot start more than two threads there must be another reason. You may be able to discover what that is by using the code listed in the BB4W Help manual under 'Accessing the Windows API... Discovering an unknown error' (or you can read it online here). Copy that code into your program and use it to discover the Windows error when your thread creation fails.
Quote:| The code to create the codes in ASM is |
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Creating a thread using assembler code is unusual and probably makes it rather more difficult to debug. Do you need to? Couldn't you create all the threads you need initially, using BASIC code? There's a considerable overhead in creating a thread so it's more efficient to create it just once, at the start, rather than to repetitively terminate the thread and then create another one.
Richard.
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svein
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Re: Parallel Assembly
« Reply #13 on: Jun 22nd, 2017, 6:12pm » |
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Ric:
This might get you started, don't know who wrote it.
Disregard the middle bit (system info).
Code: REM!WC MAXIMUM_PROCESSORS = 32 CREATE_SUSPENDED = &4 INFINITE = &FFFFFFFF _TRUE = 1 A% = 1 B% = 1 :\ \\ assemble two different (pointless) routines to increment A% and B% \ DIM code 50, L%-1 FOR pass=8 TO 10 STEP 2 P% = code [ OPT pass .ThreadProc1 inc dword [^A%] cmp dword [^A%],0 jne ThreadProc1 ret .ThreadProc2 inc dword [^B%] cmp dword [^B%],0 jne ThreadProc2 ret ] NEXT :\ \\ Declare SYSTEM_INFO structure \ DIM _SYSTEM_INFO{ wProcessorArchitecture%, \ Only lower word if valid: high word is wReserved - was dwOemID \ dwPageSize%, \ \ lpMinimumApplicationAddress%, \ \ lpMaximumApplicationAddress%, \ \ dwActiveProcessorMask%, \ \ dwNumberOfProcessors%, \ \ dwProcessorType%, \ \ dwAllocationGranulatiry%, \ \ wProcessorLevel{l&,h&}, \ \ wProcessorRevision{l&,h&} } SYS "GetSystemInfo", _SYSTEM_INFO{} PRINT "Number of processors available: ";_SYSTEM_INFO.dwNumberOfProcessors% :\ \\ Create the threads and store their handles in an array \ DIM hThread%(1) :\ \\ ON ERROR and ON CLOSE to cleanup thread handles \ ON ERROR PROCCleanup:REPORT:END ON CLOSE PROCCleanup:QUIT :\ \\ Create the threads in a suspended state \ SYS "CreateThread", 0, 1024, ThreadProc1, 0, CREATE_SUSPENDED, 0 TO hThread%(0) IF hThread%(0) = 0 THEN ERROR,"Failed to create Thread 1." SYS "CreateThread", 0, 1024, ThreadProc2, 0, CREATE_SUSPENDED, 0 TO hThread%(1) IF hThread%(1) = 0 THEN ERROR,"Failed to create Thread 2." :\ \\ Get the current ideal processor for each thread \ SYS "SetThreadIdealProcessor", hThread%(0), MAXIMUM_PROCESSORS TO current0% PRINT "Thread 1 is currently on : ";current0% SYS "SetThreadIdealProcessor", hThread%(1), MAXIMUM_PROCESSORS TO current1% PRINT "Thread 2 is currently on : ";current1% IF current0% = current1% AND _SYSTEM_INFO.dwNumberOfProcessors%>1 THEN SYS "SetThreadIdealProcessor", hThread%(1), 1 TO R% IF R%=-1 THEN PRINT"Couldn't change the processor for the 2nd thread." ENDIF :\ \\ Wait a bit, check out Task Manager maybe... \ PRINT "Waiting....." WAIT 500 PRINT "Starting threads." PRINT A%,B% :\ \\ |||Fry||| those processors \ SYS "ResumeThread", hThread%(0) SYS "ResumeThread", hThread%(1) :\ \\ Wait until both threads have stopped and then exit \ SYS "WaitForMultipleObjects", 2, ^hThread%(0), _TRUE, INFINITE TO R% PRINT A%,B% PROCCleanup END :\ \\ Close the thread objects \ DEFPROCCleanup FOR I%=0 TO 1 IF hThread%(I%) THEN SYS "CloseHandle", hThread%(I%) : hThread%(I%) = 0 NEXT ENDPROC
Svein
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Richard Russell
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Re: Parallel Assembly
« Reply #14 on: Jun 22nd, 2017, 7:51pm » |
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on Jun 22nd, 2017, 6:12pm, svein wrote:| This might get you started, don't know who wrote it. |
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It's important to note this comment:
Code: \\ |||Fry||| those processors
... and it certainly does! I would be very cautious about running this program unless you are confident about the efficiency of your CPU's cooling system!
Another thing to note is that, as it stands, the program cannot be terminated other than by using Task Manager (which will kill the BB4W IDE at the same time); the threads would exit eventually but only after 2^32 loops!
I wonder if the original author thought that closing a thread's handle terminates the thread (there's an ON CLOSE handler that closes both thread handles) but it doesn't. In fact it's perfectly OK to close a thread's handle immediately after it has been started; it won't affect anything unless the handle is needed later.
I would prefer to adapt the program so that the threads are forced to terminate on clicking Close, which can be achieved by changing the last few lines as follows:
Code: REM Wait until both threads have stopped and then exit REPEAT SYS "WaitForMultipleObjects", 2, ^hThread%(0), _TRUE, 100 TO R% UNTIL R% <> 258 PRINT A%,B% PROCCleanup END REM Close the thread objects DEFPROCCleanup A% = TRUE : B% = TRUE FOR I%=0 TO 1 IF hThread%(I%) THEN SYS "CloseHandle", hThread%(I%) : hThread%(I%) = 0 NEXT ENDPROC
My final suggestion would be to give careful thought to whether 'SetThreadIdealProcessor' or 'SetThreadAffinityMask' is most appropriate for your program.
Richard.
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Ric
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Re: Parallel Assembly
« Reply #15 on: Jun 23rd, 2017, 5:33pm » |
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Thanks guys, I have managed to create the style of code I was after which works very similar to the last two posts. I have had to go off on a tangent, but will be back to this at a later date.
Ric
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