Memory Block
BlitzMax Forums/BlitzMax Programming/Memory Block
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| Hello, Does anyone know if I can allocate a large block of memory, referenced by pointer. Then I can write Ints and Floats, etc into arbitary points within this block? I havent had any time to test this out myself or look it up because I havent been at my BMX computer for days. Im asking this because im writing a small interprative emulator for my own virtual cpu and I need this for both speed and simplicity. I know that banks have this ability but I realy want to try and avoid the overhead of the function calls. Perhaps someone knows also if using this method will use the CPU cache efficiently, because I heard way back that BlitzBasic banks missed the cache. Thanks |
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| MemAlloc should do that, but you can just as well use an array. |
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| If you plan to use it within BM, don't use MemAlloc but TBank and CreateBank. |
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| @Dreamora Using TBank, will that not give me overhead on the function calls? @grable Can I just use MemAlloc to get a pointer to a block of memory then do this: local a:float = 0.4432 ' example values local b:int = 1232 pointer[ mem_address1 ] = a pointer[ mem_address2 ] = b Will that poke both ints and floats into the memory? If so then that is excactly what im after. |
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| Ok, I just coded up a small sample: Global pointer:Byte Ptr pointer = MemAlloc( 255 ) MemClear( pointer, 255 ) pointer[0] = Int( 123 ) pointer[2] = Float( 1.45 ) This compiles and appears to be working. The problem is that as the float is placed into the memory location it is cast to a byte and therefore loses all precision. Is there anyway around this. I realy dont want to resort to fixed point numbers for speed reasons. Perhaps im just indexing the memory wrong for my read/write opperations. Thanks |
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| Global pointer:Byte Ptr pointer = MemAlloc( 255 ) MemClear( pointer, 255 ) Global intpointer:Int Ptr = Int Ptr(pointer) Global floatpointer:Float Ptr = Float Ptr(pointer) intpointer[0] = Int( 123 ) floatpointer[1] = Float( 1.45 ) |
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| Cool, thanks very much. I had a look at the TBank source and this is the same way it was done there. |
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