#include "base/system.h"

uint32_t currentSize = 0;
using namespace std;

void Kernel::syscall(int num, uint32_t arg0, uint32_t arg1, uint32_t arg2, uint32_t arg3)
{
    uint32_t newSize = arg0;
    uint32_t heapStart = userModeHeap.base;

    //om new-size(arg0) är mindre
    if(newSize < currentSize ) {

        for (uint32_t i = heapStart + currentSize; i >= heapStart + newSize; i-=4096) {
          /* "ta bort pages" */
          freeFrame(mmu.cr3.tables[i>>22]->entries[(i>>12)&0x3ff].frame);
          mmu.cr3.tables[i>>22]->entries[(i>>12)&0x3ff].present = false;
          mmu.cr3.tables[i>>22]->entries[(i>>12)&0x3ff].frame = 0;
        }
      currentSize = newSize;
    }
    //om new-size(arg0) är större
    else if(newSize > currentSize) {
        for (uint32_t i = currentSize; i < heapStart + newSize; i+=4096) {
          //skapar pagetable vid pagedir
            if(mmu.cr3.tables[i>>22] == NULL){
              mmu.cr3.tables[i>>22] = new PageTable();
              cout << "New PageTable created" << endl;
            }

          /* "lägg till pages" */
          //cout<<"A1"<<endl;
          mmu.cr3.tables[i>>22]->entries[(i>>12)&0x3ff].present = true;
          mmu.cr3.tables[i>>22]->entries[(i>>12)&0x3ff].frame = allocateFrame();
          //cout<<"A2"<<endl;
        }
      currentSize = newSize;
    }


      printf("output: syscall %d arg0=%08x arg1=%08x arg2=%08x arg3=%08x\n", num, arg0, arg1, arg2, arg3);

    switch(num) {
        case SYS_BRK:
            std::cout << "Brk is not implemented" << std::endl;
            return;
        default:
            std::cout << "Unrecognised syscall: " << num << std::endl;
            return;
  }
}


void Kernel::pageFaultHandler(uint32_t vaddr)
{
    printf("output: Page fault! addr=%08x\n",vaddr);
    throw std::string("output: Program segv");
}