Package mars.simulator

Class Exceptions

java.lang.Object
mars.simulator.Exceptions
public class Exceptions extends Object
Represents an error/interrupt that occurs during execution (simulation).
Version:
August 2005
Author:
Pete Sanderson

  • Field Details

    • EXTERNAL_INTERRUPT_KEYBOARD

      public static final int EXTERNAL_INTERRUPT_KEYBOARD
      The exception number is stored in coprocessor 0 cause register ($13) Note: the codes for External Interrupts have been modified from MIPS specs in order to encode two pieces of information. According to spec, there is one External Interrupt code, 0. But then how to distinguish keyboard interrupt from display interrupt? The Cause register has Interrupt Pending bits that can be set. Bit 8 represents keyboard, bit 9 represents display. Those bits are included into this code, but shifted right two positions since the interrupt code will be shifted left two positions for inserting cause code into bit positions 2-6 in Cause register. DPS 23 July 2008.
      See Also:
      Constant Field Values

    • EXTERNAL_INTERRUPT_DISPLAY

      public static final int EXTERNAL_INTERRUPT_DISPLAY
      See Also:
      Constant Field Values

    • ADDRESS_EXCEPTION_LOAD

      public static final int ADDRESS_EXCEPTION_LOAD
      See Also:
      Constant Field Values

    • ADDRESS_EXCEPTION_STORE

      public static final int ADDRESS_EXCEPTION_STORE
      See Also:
      Constant Field Values

    • SYSCALL_EXCEPTION

      public static final int SYSCALL_EXCEPTION
      See Also:
      Constant Field Values

    • BREAKPOINT_EXCEPTION

      public static final int BREAKPOINT_EXCEPTION
      See Also:
      Constant Field Values

    • RESERVED_INSTRUCTION_EXCEPTION

      public static final int RESERVED_INSTRUCTION_EXCEPTION
      See Also:
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    • ARITHMETIC_OVERFLOW_EXCEPTION

      public static final int ARITHMETIC_OVERFLOW_EXCEPTION
      See Also:
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    • TRAP_EXCEPTION

      public static final int TRAP_EXCEPTION
      See Also:
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    • DIVIDE_BY_ZERO_EXCEPTION

      public static final int DIVIDE_BY_ZERO_EXCEPTION
      See Also:
      Constant Field Values

    • FLOATING_POINT_OVERFLOW

      public static final int FLOATING_POINT_OVERFLOW
      See Also:
      Constant Field Values

    • FLOATING_POINT_UNDERFLOW

      public static final int FLOATING_POINT_UNDERFLOW
      See Also:
      Constant Field Values

  • Constructor Details

    • Exceptions

      public Exceptions()

  • Method Details

    • setRegisters

      public static void setRegisters​(int cause)
      Given MIPS exception cause code, will place that code into coprocessor 0 CAUSE register ($13), set the EPC register to "current" program counter, and set Exception Level bit in STATUS register.
      Parameters:
      cause - The cause code (see Exceptions for a list)

    • setRegisters

      public static void setRegisters​(int cause, int addr)
      Given MIPS exception cause code and bad address, place the bad address into VADDR register ($8) then call overloaded setRegisters with the cause code to do the rest.
      Parameters:
      cause - The cause code (see Exceptions for a list). Should be address exception.
      addr - The address that caused the exception.