avrora.sim
Interface State

All Superinterfaces:

IORegisterConstants

All Known Implementing Classes:

BaseInterpreter

public interface State

extends IORegisterConstants

The State class represents the state of the simulator, including the contents of registers and memory.

Nested Class Summary

static interface	State.IOReg The IOReg interface models the behavior of an IO register.
static class	State.RWIOReg The RWIOReg class is an implementation of an IO register that has the simple, default behavior of being able to read and write just as a general purpose register or byte in SRAM.

Field Summary

static State.IOReg

RESERVED The RESERVED field of the state class represents an instance of the IOReg interface that will not allow any writes to this register to occur.

Fields inherited from interface avrora.sim.IORegisterConstants

ACSR, ADCH, ADCL, ADCSRA, ADMUX, ASSR, DDRA, DDRB, DDRC, DDRD, DDRE, DDRF, DDRG, EEARH, EEARL, EECR, EEDR, EICRA, EICRB, EIFR, EIMSK, ETIFR, ETIMSK, ICR1H, ICR1L, ICR3H, ICR3L, MCUCR, MCUCSR, NUM_REGS, OCDR, OCR0, OCR1AH, OCR1AL, OCR1BH, OCR1BL, OCR1CH, OCR1CL, OCR2, OCR3AH, OCR3AL, OCR3BH, OCR3BL, OCR3CH, OCR3CL, OSCCAL, PINA, PINB, PINC, PIND, PINE, PINF, PING, PORTA, PORTB, PORTC, PORTD, PORTE, PORTF, PORTG, RAMPZ, SFIOR, SPCR, SPDR, SPH, SPL, SPMCSR, SPSR, SREG, SREG_C, SREG_H, SREG_I, SREG_N, SREG_S, SREG_T, SREG_V, SREG_Z, TCCR0, TCCR1A, TCCR1B, TCCR1C, TCCR2, TCCR3A, TCCR3B, TCCR3C, TCNT0, TCNT1H, TCNT1L, TCNT2, TCNT3H, TCNT3L, TIFR, TIMSK, TWAR, TWBR, TWCR, TWDR, TWSR, UBRR0H, UBRR0L, UBRR1H, UBRR1L, UCSR0A, UCSR0B, UCSR0C, UCSR1A, UCSR1B, UCSR1C, UDR0, UDR1, WDTCR, XDIV, XMCRA, XMCRB

Method Summary

long	getCycles() The getCycles() method returns the clock cycle count recorded so far in the simulation.
byte	getDataByte(int address) The getDataByte() method reads a byte value from the data memory (SRAM) at the specified address.
boolean	getFlag_C() The getFlag_C() method returns the current value of the C bit in the status register as a boolean.
boolean	getFlag_H() The getFlag_H() method returns the current value of the H bit in the status register as a boolean.
boolean	getFlag_I() The getFlag_I() method returns the current value of the I bit in the status register as a boolean.
boolean	getFlag_N() The getFlag_N() method returns the current value of the N bit in the status register as a boolean.
boolean	getFlag_S() The getFlag_S() method returns the current value of the S bit in the status register as a boolean.
boolean	getFlag_T() The getFlag_T() method returns the current value of the T bit in the status register as a boolean.
boolean	getFlag_V() The getFlag_V() method returns the current value of the V bit in the status register as a boolean.
boolean	getFlag_Z() The getFlag_Z() method returns the current value of the Z bit in the status register as a boolean.
Instr	getInstr(int address) The getInstr() can be used to retrieve a reference to the Instr object representing the instruction at the specified program address.
State.IOReg	getIOReg(int ioreg) The getIOReg() method is used to retrieve a reference to the actual IOReg instance stored internally in the state.
byte	getIORegisterByte(int ioreg) The getIORegisterByte() method reads the value of an IO register.
int	getPC() The getPC() retrieves the current program counter.
long	getPostedInterrupts() The getPostedInterrupts() method returns a mask that represents all interrupts that are currently pending (meaning they are ready to be fired in priority order as long as the I flag is on).
byte	getProgramByte(int address) The getProgramByte() method reads a byte value from the program (Flash) memory.
byte	getRegisterByte(Register reg) Read a general purpose register's current value as a byte.
int	getRegisterUnsigned(Register reg) Read a general purpose register's current value as an integer, without any sign extension.
int	getRegisterWord(Register reg) Read a general purpose register pair as an unsigned word.
int	getSP() The getSP() method reads the current value of the stack pointer.
byte	getSREG() The getSREG() method reads the value of the status register.
byte	getStackByte() The getStackByte() method reads a byte from the address specified by SP+1.
boolean	isSleeping() The isSleeping() method returns whether the simulator is currently in a sleep mode.

Field Detail

RESERVED

public static final State.IOReg RESERVED

The RESERVED field of the state class represents an instance of the IOReg interface that will not allow any writes to this register to occur. These reserved IO registers are specified in the hardware manuals.

Method Detail

getPostedInterrupts

public long getPostedInterrupts()

The getPostedInterrupts() method returns a mask that represents all interrupts that are currently pending (meaning they are ready to be fired in priority order as long as the I flag is on).

Returns:

a mask representing the interrupts which are posted for processing

getRegisterByte

public byte getRegisterByte(Register reg)

Read a general purpose register's current value as a byte.

Parameters:

reg - the register to read

Returns:

the current value of the register

getRegisterUnsigned

public int getRegisterUnsigned(Register reg)

Read a general purpose register's current value as an integer, without any sign extension.

Parameters:

reg - the register to read

Returns:

the current unsigned value of the register

getRegisterWord

public int getRegisterWord(Register reg)

Read a general purpose register pair as an unsigned word. This method will read the value of the specified register and the value of the next register in numerical order and return the two values combined as an unsigned integer The specified register should be less than r31, because r32 (the next register) does not exist.

Parameters:

reg - the low register of the pair to read

Returns:

the current unsigned word value of the register pair

getSREG

public byte getSREG()

The getSREG() method reads the value of the status register. The status register contains the I, T, H, S, V, N, Z, and C flags, in order from highest-order to lowest-order.

Returns:

the value of the status register as a byte.

getFlag_I

public boolean getFlag_I()

The getFlag_I() method returns the current value of the I bit in the status register as a boolean.

Returns:

the value of the flag

getFlag_T

public boolean getFlag_T()

The getFlag_T() method returns the current value of the T bit in the status register as a boolean.

Returns:

the value of the flag

getFlag_H

public boolean getFlag_H()

The getFlag_H() method returns the current value of the H bit in the status register as a boolean.

Returns:

the value of the flag

getFlag_S

public boolean getFlag_S()

The getFlag_S() method returns the current value of the S bit in the status register as a boolean.

Returns:

the value of the flag

getFlag_V

public boolean getFlag_V()

The getFlag_V() method returns the current value of the V bit in the status register as a boolean.

Returns:

the value of the flag

getFlag_N

public boolean getFlag_N()

The getFlag_N() method returns the current value of the N bit in the status register as a boolean.

Returns:

the value of the flag

getFlag_Z

public boolean getFlag_Z()

The getFlag_Z() method returns the current value of the Z bit in the status register as a boolean.

Returns:

the value of the flag

getFlag_C

public boolean getFlag_C()

The getFlag_C() method returns the current value of the C bit in the status register as a boolean.

Returns:

the value of the flag

getStackByte

public byte getStackByte()

The getStackByte() method reads a byte from the address specified by SP+1. This method should not be called with an empty stack, as it will cause an exception consistent with trying to read non-existent memory.

Returns:

the value on the top of the stack

getSP

public int getSP()

The getSP() method reads the current value of the stack pointer. Since the stack pointer is stored in two IO registers, this method will cause the invocation of the .read() method on each of the IOReg objects that store these values.

Returns:

the value of the stack pointer as a byte address

getPC

public int getPC()

The getPC() retrieves the current program counter.

Returns:

the program counter as a byte address

getInstr

public Instr getInstr(int address)

The getInstr() can be used to retrieve a reference to the Instr object representing the instruction at the specified program address. Care should be taken that the address in program memory specified does not contain data. This is because Avrora does have a functioning disassembler and assumes that the Instr objects for each instruction in the program are known a priori.

Parameters:

address - the byte address from which to read the instruction

Returns:

a reference to the Instr object representing the instruction at that address in the program

getDataByte

public byte getDataByte(int address)

The getDataByte() method reads a byte value from the data memory (SRAM) at the specified address.

Parameters:

address - the byte address to read

Returns:

the value of the data memory at the specified address

Throws:

java.lang.ArrayIndexOutOfBoundsException - if the specified address is not the valid memory range

getProgramByte

public byte getProgramByte(int address)

The getProgramByte() method reads a byte value from the program (Flash) memory. The flash memory generally stores read-only values and the instructions of the program. Care should be taken that the program memory at the specified address does not contain an instruction. This is because, in general, programs should not read instructions as data, and secondly, because no assembler is present in Avrora and therefore the actual byte value of an instruction may not be known.

Parameters:

address - the byte address at which to read

Returns:

the byte value of the program memory at the specified address

Throws:

java.lang.ArrayIndexOutOfBoundsException - if the specified address is not the valid program memory range

getIORegisterByte

public byte getIORegisterByte(int ioreg)

The getIORegisterByte() method reads the value of an IO register. Invocation of this method causes an invocatiobn of the .read() method on the corresponding internal IOReg object, and its value returned.

Parameters:

ioreg - the IO register number

Returns:

the value of the IO register

getIOReg

public State.IOReg getIOReg(int ioreg)

The getIOReg() method is used to retrieve a reference to the actual IOReg instance stored internally in the state. This is generally only used in the simulator and device implementations, and clients should probably not call this memory directly.

Parameters:

ioreg - the IO register number to retrieve

Returns:

a reference to the IOReg instance of the specified IO register

getCycles

public long getCycles()

The getCycles() method returns the clock cycle count recorded so far in the simulation.

Returns:

the number of clock cycles elapsed in the simulation

isSleeping

public boolean isSleeping()

The isSleeping() method returns whether the simulator is currently in a sleep mode.

Returns:

true if the simulator is in a sleep mode; false otherwise