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JIT: completely inline timer reading #975

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Sep 5, 2014
Merged

JIT: completely inline timer reading #975

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8 changes: 4 additions & 4 deletions Source/Core/Core/CoreTiming.cpp
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Expand Up @@ -50,13 +50,13 @@ static Event *eventPool = nullptr;
int slicelength;
static int maxSliceLength = MAX_SLICE_LENGTH;

static s64 globalTimer;
static s64 idledCycles;

static u32 fakeDecStartValue;
static u64 fakeDecStartTicks;
static u64 fakeTBStartValue;
static u64 fakeTBStartTicks;

s64 globalTimer;
u64 fakeTBStartValue;
u64 fakeTBStartTicks;

static int ev_lost;

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4 changes: 4 additions & 0 deletions Source/Core/Core/CoreTiming.h
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Expand Up @@ -25,6 +25,10 @@ class PointerWrap;
namespace CoreTiming
{

extern s64 globalTimer;
extern u64 fakeTBStartValue;
extern u64 fakeTBStartTicks;

void Init();
void Shutdown();

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21 changes: 16 additions & 5 deletions Source/Core/Core/PowerPC/Jit64/Jit_SystemRegisters.cpp
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Expand Up @@ -173,15 +173,25 @@ void Jit64::mfspr(UGeckoInstruction inst)
// typical use of this instruction is to call it three times, e.g. mftbu/mftbl/mftbu/cmpw/bne
// to deal with possible timer wraparound. This makes the second two (out of three) completely
// redundant for the JIT.
u32 registersInUse = CallerSavedRegistersInUse();
u32 offset = js.downcountAmount / SystemTimers::TIMER_RATIO;
ABI_PushRegistersAndAdjustStack(registersInUse, false);
ABI_CallFunction((void *)&SystemTimers::GetFakeTimeBase);
ABI_PopRegistersAndAdjustStack(registersInUse, false);
gpr.FlushLockX(EDX);

// An inline implementation of CoreTiming::GetFakeTimeBase, since in timer-heavy games the
// cost of calling out to C for this is actually significant.
MOV(64, R(RAX), M(&CoreTiming::globalTimer));
SUB(64, R(RAX), M(&CoreTiming::fakeTBStartTicks));
// a / 12 = (a * 0xAAAAAAAAAAAAAAAB) >> 67
MOV(64, R(RDX), Imm64(0xAAAAAAAAAAAAAAABULL));
MUL(64, R(RDX));
MOV(64, R(RAX), M(&CoreTiming::fakeTBStartValue));
SHR(64, R(RDX), Imm8(3));
// The timer can change within a long block, so add in any difference
if (offset > 0)
ADD(64, R(RAX), Imm32(offset));
LEA(64, RAX, MComplex(RAX, RDX, SCALE_1, offset));
else
ADD(64, R(RAX), R(RDX));
MOV(64, M(&TL), R(RAX));

// Two calls of TU/TL next to each other are extremely common in typical usage, so merge them
// if we can.
u32 nextIndex = (js.next_inst.SPRU << 5) | (js.next_inst.SPRL & 0x1F);
Expand Down Expand Up @@ -225,6 +235,7 @@ void Jit64::mfspr(UGeckoInstruction inst)
break;
}
gpr.UnlockAll();
gpr.UnlockAllX();
}

void Jit64::mtmsr(UGeckoInstruction inst)
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