/************************
 *** Team Kitty, 2019 ***
 ***       Sync       ***
 ***********************/

/* This file contains all of the functions required to handle
 * the system handover from Syncboot.
 */

#include <kernel.h>

static void UpdateSegments(void);
static void InstallInterrupt(size_t ISR, size_t Function);
static void InstallTrap(size_t ISR, size_t Function);



/* Main system handover from UEFI.
 * Prepares the processor, the screen, and memory. */
void PrepareSystem(FILELOADER_PARAMS* FLOP) {
    Memory_Info.MemoryMap = FLOP->MemoryMap;
    Memory_Info.MemoryMapSize = FLOP->MemoryMap_Size;
    Memory_Info.MemoryMapDescriptorSize = FLOP->MemoryMapDescriptorSize;
    Memory_Info.MemoryMapDescriptorVersion = FLOP->MemoryMapDescriptorVersion;

    if(SetIdentityMap(FLOP->RTServices) == NULL) {
        Memory_Info.MemoryMap = FLOP->MemoryMap;
    }

    SetupPrinting(FLOP->GPU_Info->GPUs[0]);
    /* All print functions are now available. */

    PrepareAVX();



    /* Bit 5 of CR0 is Numeric Error, which enables
     * the internal x87 Floating Point Math error
     * reporting. */
    size_t CR0 = ReadControlRegister(0);
    // Mask CR0 to only see bit 5
    if( !(CR0 & (1 << 5))) {
        // Preserve CR0, but set bit 5.
        size_t TempReg = CR0 ^ (1 << 5);
        // Write it back
        WriteControlRegister(0, TempReg);

        // Double check. Some processors can be tricky.
        TempReg = ReadControlRegister(CR0);
        if(TempReg == CR0)
            printf("Error setting CR0.NE\r\n");

    }

    /* Bit 10 of CR4 is OSXMMEXCPT, which enables
     * SSE instructions. */
    size_t CR4 = ReadControlRegister(4);
    // Mask CR4 to only see bit 10
    if( !(CR4 & (1 << 10))) {
        // Preserve CR4, but set bit 10.
        size_t TempReg = CR4 ^ (1 << 10);
        // Write it back
        WriteControlRegister(4, TempReg);

        // Double check. Some processors can be tricky.
        TempReg = ReadControlRegister(4);
        if(TempReg == CR4)
            printf("Error setting CR4.OSXMMEXCPT\r\n");
    }

    // Set up memory management
    InstallGDT();
    InstallIDT();
    InstallMemoryMap();
    InstallPaging();

    // Clean up UEFI's mess
    ReclaimEfiBootServicesMemory();
    ReclaimEfiLoaderCodeMemory();

    // Let Intel ME take over power management
    PreparePowerManagement();

}

/* A temporary system for keeping track of system performance. */

size_t ClockTick() {

    // We will be reading a register, so we need to split it up.
    size_t RegHigh = 0, RegLow = 0;
    
    __asm__ __volatile__("rdtscp" : "=a" (RegLow), "=d" (RegHigh) : : "%rcx");

}