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https://gitea.wildfiregames.com/0ad/0ad.git
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janwas
c0ed950657
this snowballed into a massive search+destroy of the hodgepodge of mostly equivalent types we had in use (int, uint, unsigned, unsigned int, i32, u32, ulong, uintN). it is more efficient to use 64-bit types in 64-bit mode, so the preferred default is size_t (for anything remotely resembling a size or index). tile coordinates are ssize_t to allow more efficient conversion to/from floating point. flags are int because we almost never need more than 15 distinct bits, bit test/set is not slower and int is fastest to type. finally, some data that is pretty much directly passed to OpenGL is now typed accordingly. after several hours, the code now requires fewer casts and less guesswork. other changes: - unit and player IDs now have an "invalid id" constant in the respective class to avoid casting and -1 - fix some endian/64-bit bugs in the map (un)packing. added a convenience function to write/read a size_t. - ia32: change CPUID interface to allow passing in ecx (required for cache topology detection, which I need at work). remove some unneeded functions from asm, replace with intrinsics where possible. This was SVN commit r5942.
105 lines
3.2 KiB
C++
105 lines
3.2 KiB
C++
/**
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* =========================================================================
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* File : counter.cpp
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* Project : 0 A.D.
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* Description : Interface for counter implementations
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* =========================================================================
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*/
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// license: GPL; see lib/license.txt
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#include "precompiled.h"
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#include "counter.h"
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#include "lib/bits.h"
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#include "lib/sysdep/cpu.h" // cpu_CAS
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#include "tsc.h"
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#include "hpet.h"
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#include "pmt.h"
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#include "qpc.h"
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#include "tgt.h"
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// to add a new counter type, simply include its header here and
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// insert a case in ConstructCounterAt's switch statement.
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//-----------------------------------------------------------------------------
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// create/destroy counters
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/**
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* @return pointer to a newly constructed ICounter subclass of type <id> at
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* the given address, or 0 iff the ID is invalid.
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* @param size maximum allowable size [bytes] of the subclass instance
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**/
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static ICounter* ConstructCounterAt(size_t id, void* address, size_t size)
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{
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// rationale for placement new: see call site.
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// counters are chosen according to the following order. rationale:
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// - TSC must come before QPC and PMT to make sure a bug in the latter on
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// Pentium systems doesn't come up.
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// - PMT works, but is inexplicably slower than QPC on a PIII Mobile.
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// - TGT really isn't as safe as the others, so it should be last.
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// - low-overhead and high-resolution counters are preferred.
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switch(id)
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{
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case 0:
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debug_assert(sizeof(CounterHPET) <= size);
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return new(address) CounterHPET();
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case 1:
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debug_assert(sizeof(CounterTSC) <= size);
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return new(address) CounterTSC();
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case 2:
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debug_assert(sizeof(CounterQPC) <= size);
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return new(address) CounterQPC();
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case 3:
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debug_assert(sizeof(CounterPMT) <= size);
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return new(address) CounterPMT();
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case 4:
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debug_assert(sizeof(CounterTGT) <= size);
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return new(address) CounterTGT();
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default:
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return 0;
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}
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}
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static volatile uintptr_t isCounterAllocated;
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ICounter* CreateCounter(size_t id)
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{
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// we placement-new the Counter classes in a static buffer.
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// this is dangerous, but we are careful to ensure alignment. it is
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// unusual and thus bad, but there's also one advantage: we avoid
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// using global operator new before the CRT is initialized (risky).
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//
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// alternatives:
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// - defining as static doesn't work because the ctors (necessary for
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// vptr initialization) run during _cinit, which comes after our
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// first use of them.
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// - using static_calloc isn't possible because we don't know the
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// size until after the alloc / placement new.
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if(!cpu_CAS(&isCounterAllocated, 0, 1))
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debug_assert(0); // static counter memory is already in use!
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static const size_t memSize = 200;
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static u8 mem[memSize];
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u8* alignedMem = (u8*)round_up((uintptr_t)mem, (uintptr_t)16u);
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const size_t bytesLeft = mem+memSize - alignedMem;
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ICounter* counter = ConstructCounterAt(id, alignedMem, bytesLeft);
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return counter;
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}
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void DestroyCounter(ICounter*& counter)
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{
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debug_assert(counter);
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counter->Shutdown();
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counter->~ICounter(); // must be called due to placement new
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counter = 0;
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isCounterAllocated = 0;
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}
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