Threading.h

#pragma once

#include "stdafx.h"

enum scrThreadState : unsigned int {
    scrThreadStateIdle,
    scrThreadStateRunning,
    scrThreadStateKilled,
    scrThreadState3, // dont know but it wont execute if this is the case (scrThread::Run)
};

struct scrThreadContext {
    unsigned int ThreadID; // 0x04
    unsigned int ProgramID; // 0x08 (*.xsc + 0x38)
    scrThreadState ThreadState; // 0x0C
    char _0x10[0x0C];
    unsigned int TimerA; // 0x1C
    unsigned int TimerB; // 0x20
    float WaitTime; // 0x24
    char _0x28[0x1C];
    unsigned int AllocatedStackSize; // 0x40
    char _0x44[0x0C];
}; // size 0x50

class scrThread {
public:
    virtual void scrThread_ctr() {};
    virtual void Reset(int ProgramID, void *Args, int ArgCount) = 0;
    virtual scrThreadState Run(int OpsToExecute) = 0;
    virtual scrThreadState Tick(int OpsToExecute) = 0;
    virtual void Kill() = 0;

    scrThreadContext Context; // 0x04
    void *Stack; // 0x54
    char _0x58[0x0C];
    char *KillMessage; // 0x64
}; // size 0x68

class GtaThread : public scrThread {
public:
    char ThreadName[24]; // 0x68
    char _0x80[0x0C];
    int NumberOfEvents; // 0x8C - not sure
    char _0x90[0x47];
    // char MissionFlag; // 0xD0
    char CanBePaused; // 0xD7
    char CanRemoveBlipsCreatedByAnyScript; // 0xD8
}; // size unknown

class ScriptHookThread : public GtaThread {
protected:
    void Reset(int ProgramID, void *Args, int ArgCount);
    scrThreadState Run(int OpsToExecute);
    scrThreadState Tick(int OpsToExecute);
    void Kill();
private:
    WORD ThreadIndex;
    PVOID StartAddress;
public:
    BOOL ScriptInitializedCalled;
    ScriptHookThread(PVOID lpStartAddress, PBOOL Result);
    ~ScriptHookThread();
};

// GtaThread scrThread
// TickThreads() -> GtaThread::Tick() -> scrThread::Tick() -> scrThread::Run()

// 0x83B435C4 opsToExecute
// 0x83DCD1E8 currentScriptName
// 0x83DCD600 globals

/*

bool TickThreads(unsigned int opsToExecute)
{
    if(opsToExecute == 0) {
        opsToExecute = 1000000;
    }

    bool r = false;

    // just enumerates the thread pool then executes the GtaThread::Tick for each thread.

    for(int i = 0; i < ThreadPool->Count; i++) {
        GtaThread *Thread = ThreadPool->Threads[i];
        if(Thread->Context.ThreadID != NULL) {
            Thread::Tick();
        }
    }

    return r;
}

If we look at the native TIMERA

lwz       r11, 0(r13)   # Load Word and Zero
li        r10, 0x134    # Load Immediate
lwz       r9, 0(r3)     # Load Word and Zero
lwzx      r8, r10, r11  # Load Word and Zero Indexed
lwz       r7, 0x1C(r8)  # Load Word and Zero
stw       r7, 0(r9)     # Store Word
blr

makes sense now
in scrThread::Run the r13 is packed with the GtaThread parameter

TlsValue(0); // ??

tls_index_0 + 0x134 = GtaThread

*/