/*
    ChibiOS/RT - Copyright (C) 2006-2007 Giovanni Di Sirio.

    This file is part of ChibiOS/RT.

    ChibiOS/RT is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 3 of the License, or
    (at your option) any later version.

    ChibiOS/RT is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#include <windows.h>
#include <stdio.h>

#undef CDECL

/**
 * @addtogroup WIN32SIM_CORE
 * @{
 */

#include <ch.h>

static LARGE_INTEGER nextcnt;
static LARGE_INTEGER slice;

void InitSimCom1(void);
void InitSimCom2(void);
BOOL Com1ConnInterruptSimCom(void);
BOOL Com2ConnInterruptSimCom(void);
BOOL Com1InInterruptSimCom(void);
BOOL Com2InInterruptSimCom(void);
BOOL Com1OutInterruptSimCom(void);
BOOL Com2OutInterruptSimCom(void);

/*
 * Simulated HW initialization.
 */
void InitCore(void) {
  WSADATA wsaData;

  // Initialization.
  if (WSAStartup(2, &wsaData) != 0) {
    printf("Unable to locate a winsock DLL\n");
    exit(1);
  }

  printf("Win32 ChibiOS/RT simulator\n\n");
  printf("Thread structure %d bytes\n", sizeof(Thread));
  if (!QueryPerformanceFrequency(&slice)) {
    printf("QueryPerformanceFrequency() error");
    exit(1);
  }
  printf("Core Frequency   %u Hz\n", (int)slice.LowPart);
  slice.QuadPart /= CH_FREQUENCY;
  QueryPerformanceCounter(&nextcnt);
  nextcnt.QuadPart += slice.QuadPart;

  InitSimCom1();
  InitSimCom2();
  fflush(stdout);
}

/*
 * Interrupt simulation.
 */
void ChkIntSources(void) {
  LARGE_INTEGER n;

  if (Com1InInterruptSimCom()   || Com2InInterruptSimCom()  ||
      Com1OutInterruptSimCom()  || Com2OutInterruptSimCom() ||
      Com1ConnInterruptSimCom() || Com2ConnInterruptSimCom()) {
    if (chSchRescRequiredI())
      chSchDoRescheduleI();
    return;
  }

  // Interrupt Timer simulation (10ms interval).
  QueryPerformanceCounter(&n);
  if (n.QuadPart > nextcnt.QuadPart) {
    nextcnt.QuadPart += slice.QuadPart;
    chSysTimerHandlerI();
    if (chSchRescRequiredI())
      chSchDoRescheduleI();
  }
}

/**
 * Performs a context switch between two threads.
 * @param otp the thread to be switched out
 * @param ntp the thread to be switched in
 */
__attribute__((fastcall))
void port_switch(Thread *otp, Thread *ntp) {
  register struct intctx volatile *esp asm("esp");

  asm volatile ("push    %ebp                                   \n\t" \
                "push    %esi                                   \n\t" \
                "push    %edi                                   \n\t" \
                "push    %ebx");
  otp->p_ctx.esp = esp;
  esp = ntp->p_ctx.esp;
  asm volatile ("pop     %ebx                                   \n\t" \
                "pop     %edi                                   \n\t" \
                "pop     %esi                                   \n\t" \
                "pop     %ebp");
}

/**
 * Halts the system. In this implementation it just exits the simulation.
 */
__attribute__((fastcall))
void port_halt(void) {

  exit(2);
}

/**
 * Threads return point, it just invokes @p chThdExit().
 */
void threadexit(void) {

  asm volatile ("push    %eax                                   \n\t" \
                "call    _chThdExit");
}

/** @} */