bstacks.nc

nesC写的heed算法

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/*
 * Authors:   Philip Levis
 * History:   July 19, 2002
 *	     
 *
 */

/**
 * @author Philip Levis
 */


includes Bombilla;

module BStacks {
  provides interface BombillaStacks as Stacks;
  provides interface BombillaTypes as Types;
  uses interface BombillaError;
}


implementation {
  
  command result_t Stacks.resetStacks(BombillaContext* context) {
    context->opStack.sp = 0;
    context->rStack.sp = 0;
    return SUCCESS;
  }
  
  command result_t Stacks.pushValue(BombillaContext* context, 
				    int16_t val) {
    if (context->opStack.sp >= BOMB_OPDEPTH) {
      dbg(DBG_ERROR, "VM: Tried to push value off end of stack.\n");
      call BombillaError.error(context, BOMB_ERROR_STACK_OVERFLOW);
      return FAIL;
    }
    else {
      uint8_t sIndex = context->opStack.sp;
      context->opStack.stack[(int)sIndex].type = BOMB_TYPE_VALUE;
      context->opStack.stack[(int)sIndex].value.var = val;
      context->opStack.sp++;
      return SUCCESS;
    }
  }

  command result_t Stacks.pushReading(BombillaContext* context, 
				      uint8_t type, 
				      int16_t val) {
    if (context->opStack.sp >= BOMB_OPDEPTH) {
      dbg(DBG_ERROR, "VM: Tried to push value off end of stack.\n");
      call BombillaError.error(context, BOMB_ERROR_STACK_OVERFLOW);
      return FAIL;
    }
    else {
      uint8_t sIndex = context->opStack.sp;
      context->opStack.stack[(int)sIndex].type = BOMB_TYPE_SENSE;
      context->opStack.stack[(int)sIndex].sense.var = val;
      context->opStack.stack[(int)sIndex].sense.type = type;
      context->opStack.sp++;
      return SUCCESS;
    }
    return SUCCESS;
  }

  command result_t Stacks.pushBuffer(BombillaContext* context, 
                                     BombillaDataBuffer* buffer) {
    if (context->opStack.sp >= BOMB_OPDEPTH) {
      dbg(DBG_ERROR, "VM: Tried to push value off end of stack.\n");
      call BombillaError.error(context, BOMB_ERROR_STACK_OVERFLOW);
      return FAIL;
    }
    else {
      uint8_t sIndex = context->opStack.sp;
      context->opStack.stack[(int)sIndex].type = BOMB_TYPE_BUFFER;
      context->opStack.stack[(int)sIndex].buffer.var = buffer;
      context->opStack.sp++;
      return SUCCESS;
    }

    return SUCCESS;
  }

  command result_t Stacks.pushOperand(BombillaContext* context, 
				      BombillaStackVariable* var) {
    if (context->opStack.sp >= BOMB_OPDEPTH) {
      dbg(DBG_ERROR, "VM: Tried to push value off end of stack.\n");
      call BombillaError.error(context, BOMB_ERROR_STACK_OVERFLOW);
      return FAIL;
    }
    else {
      uint8_t sIndex = context->opStack.sp;
      context->opStack.stack[(int)sIndex] = *var;
      context->opStack.sp++;
      return SUCCESS;
    }

    return SUCCESS;
  }

  command BombillaStackVariable* Stacks.popOperand(BombillaContext* context) {

    BombillaStackVariable* var;
    if (context->opStack.sp == 0) {
      dbg(DBG_ERROR, "VM: Tried to pop off end of stack.\n");
      context->opStack.stack[0].type = BOMB_TYPE_INVALID;
      call BombillaError.error(context, BOMB_ERROR_STACK_UNDERFLOW);
      return &(context->opStack.stack[0]);
    }
    else {
      uint8_t sIndex;
      context->opStack.sp--;
      sIndex = context->opStack.sp;
      var = &(context->opStack.stack[(int)sIndex]);
      return var;
    }
    return NULL;

  }

  command result_t Stacks.pushReturnAddr(BombillaContext* context) {
    BombillaReturnStack* rStack = &(context->rStack);
    if (rStack->sp >= BOMB_CALLDEPTH) {
      dbg(DBG_ERROR, "VM: Return stack overflow.\n");
      call BombillaError.error(context, BOMB_ERROR_RSTACK_OVERFLOW);
      return FAIL;
    }
    else {
      uint8_t sIndex = rStack->sp;
      rStack->stack[(int)sIndex].capsule = context->currentCapsule;
      rStack->stack[(int)sIndex].pc = context->pc;
      rStack->sp++;
      return SUCCESS;
    }
  }

  command result_t Stacks.popReturnAddr(BombillaContext* context) {
    BombillaReturnStack* rStack = &(context->rStack);
    BombillaReturnVariable* var;
    if (rStack->sp <= 0) {
      dbg(DBG_ERROR, "VM: Return stack underflow.\n");
      call BombillaError.error(context, BOMB_ERROR_RSTACK_UNDERFLOW);
      return FAIL;
    }
    else {
      rStack->sp--;
      var = &(rStack->stack[(int)rStack->sp]);
      context->currentCapsule = var->capsule;
      context->pc = var->pc;
      return SUCCESS;
    }
  }
  command uint8_t Stacks.getOpStackDepth(BombillaContext* context) {
    return context->opStack.sp;
  }
  command uint8_t Stacks.getReturnStackDepth(BombillaContext* context) {
    return context->rStack.sp;
  }
  
  command uint8_t Types.checkTypes(BombillaContext* context,
				   BombillaStackVariable* var,
				   uint8_t types) {
    uint8_t rval = (uint8_t)(var->type & types);
    if (!rval) {
      dbg(DBG_USR1|DBG_ERROR, "VM: Operand failed type check: type = %i, allowed types = %i\n", (int)var->type, (int)types);
      call BombillaError.error(context, BOMB_ERROR_TYPE_CHECK);
    }
    return rval;
  }
}