avrora.sim
Class State

java.lang.Object
  avrora.sim.State

All Implemented Interfaces:

IORegisterConstants

public class State

extends java.lang.Object

implements 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

protected boolean[]	flag_delta
protected boolean	pc_delta
protected boolean[]	reg_delta Delta lists of things that have changed recently.
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.
protected boolean	sp_delta

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

Constructor Summary

State(Program p, int flash_size, int ioreg_size, int sram_size)
The constructor for the State class builds the internal data structures needed to store the complete state of the machine, including registers, IO registers, the SRAM, and the flash.

Method Summary

void	clearTracingState()
void	consumeCycle() The consumeCycle() method increments the cycle count of the state by one.
void	consumeCycles(long num) The consumeCycles() method increments the cycle count of the state by the specified number of cycles.
void	dump()
Instr	getCurrentInstr() The getCurrentInstr() method returns a reference to the Instr object representing the instruction at the address of the current value of the program counter.
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.
protected void	initializeIORegs()
byte	popByte() The popByte() method pops a byte from the stack by reading from the address pointed to by SP+1 and incrementing the stack pointer.
void	postInterrupt(int num) The postInterrupt() method is generally only used within the simulator which does pre-processing of interrupts before it posts them into the internal State instance.
protected void	printPair(java.lang.String n, byte val, boolean modified)
protected void	printPair(java.lang.String n, int val, boolean modified)
protected void	printPair(java.lang.String n, long val, boolean modified)
protected void	printPair(java.lang.String n, java.lang.String str, boolean modified)
void	pushByte(byte val) The pushByte() method pushes a byte onto the stack by writing to the memory address pointed to by the stack pointer and decrementing the stack pointer.
void	setDataByte(byte val, int address) The setDataByte() method writes a value to the data memory (SRAM) of the state.
void	setFlag_C(boolean val) The setFlag_C() method updates the value of the C bit in the status register.
void	setFlag_H(boolean val) The setFlag_H() method updates the value of the H bit in the status register.
void	setFlag_I(boolean val) The setFlag_I() method updates the value of the I bit in the status register.
void	setFlag_N(boolean val) The setFlag_N() method updates the value of the N bit in the status register.
void	setFlag_S(boolean val) The setFlag_S() method updates the value of the S bit in the status register.
void	setFlag_T(boolean val) The setFlag_T() method updates the value of the T bit in the status register.
void	setFlag_V(boolean val) The setFlag_V() method updates the value of the V bit in the status register.
void	setFlag_Z(boolean val) The setFlag_Z() method updates the value of the Z bit in the status register.
void	setInstr(Instr i, int address) The setInstr() method is used internally to update the instructions of the program by the simulator.
void	setIOReg(int ioreg, State.IOReg reg) The setIOReg method installs the specified IOReg object to the specified IO register number.
void	setIORegisterByte(byte val, int ioreg) The setIORegisterByte() method writes a value to the specified IO register.
void	setPC(int pc) The setPC() method updates the value of the program counter.
void	setPostedInterrupts(long mask) The setPostedInterrupts() method allows a full update to the pending list of interrupts.
void	setRegisterByte(Register reg, byte val) The setRegisterByte() method writes a value to a general purpose register.
void	setRegisterWord(Register reg, int val) The setRegisterWord method writes a word value to a general purpose register pair.
void	setSP(int val) The setSP() method updates the value of the stack pointer.
void	setSREG_bit(int bit, boolean val) The setSREG_bit() updates the value of the specified bit in the status register.
void	setSREG(byte val) The setSREG() method writes the value of the status register.
void	unpostInterrupt(int num) The unpostInterrupt() method is generally only used within the simulator which does pre-processing of interrupts before it posts them into the internal State instance.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

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.

reg_delta

protected final boolean[] reg_delta

Delta lists of things that have changed recently. These things are manipulated in the subclass TracingState.

flag_delta

protected final boolean[] flag_delta

sp_delta

protected boolean sp_delta

pc_delta

protected boolean pc_delta

Constructor Detail

State

public State(Program p,
             int flash_size,
             int ioreg_size,
             int sram_size)

The constructor for the State class builds the internal data structures needed to store the complete state of the machine, including registers, IO registers, the SRAM, and the flash. All IO registers are initialized to be instances of RWIOReg. Reserved and special IO registers must be inserted by the getIOReg() and setIOReg() methods.

Parameters:

p - the program to construct the state for

flash_size - the size of the flash (program) memory in bytes

ioreg_size - the number of IO registers

sram_size - the size of the SRAM in bytes

Method Detail

initializeIORegs

protected void initializeIORegs()

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

postInterrupt

public void postInterrupt(int num)

The postInterrupt() method is generally only used within the simulator which does pre-processing of interrupts before it posts them into the internal State instance. This method causes the specified interrupt number to be added to the pending list of interrupts Clients should not use this method directly.

Parameters:

num - the interrupt number to post

unpostInterrupt

public void unpostInterrupt(int num)

The unpostInterrupt() method is generally only used within the simulator which does pre-processing of interrupts before it posts them into the internal State instance. This method causes the specified interrupt number to be removed from the pending list of interrupts Clients should not use this method directly.

Parameters:

num - the interrupt number to post

setPostedInterrupts

public void setPostedInterrupts(long mask)

The setPostedInterrupts() method allows a full update to the pending list of interrupts. This should only be used within the simulator.

Parameters:

mask - the new pending interrupt mask

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

setRegisterByte

public void setRegisterByte(Register reg,
                            byte val)

The setRegisterByte() method writes a value to a general purpose register. This is a destructive update and should only be called from the appropriate places in the simulator.

Parameters:

reg - the register to write the value to

val - the value to write to the register

setRegisterWord

public void setRegisterWord(Register reg,
                            int val)

The setRegisterWord method writes a word value to a general purpose register pair. This is a destructive update and should only be called from the appropriate places in the simulator. The specified register and the next register in numerical order are updated with the low-order and high-order byte of the value passed, respectively. The specified register should be less than r31, since r32 (the next register) does not exist.

Parameters:

reg - the low register of the pair to write

val - the word value to write to 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.

setSREG

public void setSREG(byte val)

The setSREG() method writes the value of the status register. This method should only be called from the appropriate places in the simulator.

Parameters:

val -

setSREG_bit

public void setSREG_bit(int bit,
                        boolean val)

The setSREG_bit() updates the value of the specified bit in the status register. It should only be called from the appropriate places in the simulator.

Parameters:

bit - the number of the bit to update

val - the new value of the bit as a boolean

setFlag_I

public void setFlag_I(boolean val)

The setFlag_I() method updates the value of the I bit in the status register. It should only be called from within the simulator.

Parameters:

val - the new value of the flag

setFlag_T

public void setFlag_T(boolean val)

The setFlag_T() method updates the value of the T bit in the status register. It should only be called from within the simulator.

Parameters:

val - the new value of the flag

setFlag_H

public void setFlag_H(boolean val)

The setFlag_H() method updates the value of the H bit in the status register. It should only be called from within the simulator.

Parameters:

val - the new value of the flag

setFlag_S

public void setFlag_S(boolean val)

The setFlag_S() method updates the value of the S bit in the status register. It should only be called from within the simulator.

Parameters:

val - the new value of the flag

setFlag_V

public void setFlag_V(boolean val)

The setFlag_V() method updates the value of the V bit in the status register. It should only be called from within the simulator.

Parameters:

val - the new value of the flag

setFlag_N

public void setFlag_N(boolean val)

The setFlag_N() method updates the value of the N bit in the status register. It should only be called from within the simulator.

Parameters:

val - the new value of the flag

setFlag_Z

public void setFlag_Z(boolean val)

The setFlag_Z() method updates the value of the Z bit in the status register. It should only be called from within the simulator.

Parameters:

val - the new value of the flag

setFlag_C

public void setFlag_C(boolean val)

The setFlag_C() method updates the value of the C bit in the status register. It should only be called from within the simulator.

Parameters:

val - the new value of the flag

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

popByte

public byte popByte()

The popByte() method pops a byte from the stack by reading from the address pointed to by SP+1 and incrementing the stack pointer. This method, like all of the other methods that change the state, should probably only be used within the simulator. 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

pushByte

public void pushByte(byte val)

The pushByte() method pushes a byte onto the stack by writing to the memory address pointed to by the stack pointer and decrementing the stack pointer. This method, like all of the other methods that change the state, should probably only be used within the simulator.

Parameters:

val - the value to push onto 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

setSP

public void setSP(int val)

The setSP() method updates the value of the stack pointer. Generally the stack pointer is stored in two IO registers SPL and SPH. This method should generally only be used within the simulator.

Parameters:

val -

See Also:

IORegisterConstants

getPC

public int getPC()

The getPC() retrieves the current program counter.

Returns:

the program counter as a byte address

setPC

public void setPC(int pc)

The setPC() method updates the value of the program counter. It is generally used only by the simulator. In general it is a good idea to keep the program counter aligned on a 2-byte boundary. Clients of the State interface should generally not use this method.

Parameters:

pc - the new program counter as a byte address

getCurrentInstr

public Instr getCurrentInstr()

The getCurrentInstr() method returns a reference to the Instr object representing the instruction at the address of the current value of the program counter.

Returns:

a reference to the Instr object representing the instruction at the current program counter

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

setInstr

public void setInstr(Instr i,
                     int address)

The setInstr() method is used internally to update the instructions of the program by the simulator. This is generally for the purpose of replacing an instruction with a Simulator.ProbedInstr instance that will fire probes when it is visited. It is generally not recommended for clients of the State interface to update instructions in the program memory.

Parameters:

i - the instruction to write

address - the byte address in the program to write the instruction to

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

setDataByte

public void setDataByte(byte val,
                        int address)

The setDataByte() method writes a value to the data memory (SRAM) of the state. This is generally meant for the simulator, related classes, and device implementations to use, but could also be used by debuggers and other tools.

Parameters:

val - the value to write

address - the byte address at which to write the value

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

setIOReg

public void setIOReg(int ioreg,
                     State.IOReg reg)

The setIOReg method installs the specified IOReg object to the specified IO register number. This method is generally only used in the simulator and in device implementations to set up the state correctly during initialization.

Parameters:

ioreg - the IO register number

reg - the IOReg object to install

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

setIORegisterByte

public void setIORegisterByte(byte val,
                              int ioreg)

The setIORegisterByte() method writes a value to the specified IO register. This is generally only used internally to the simulator and device implementations, and client interfaces should probably not call this method.

Parameters:

val - the value to write to the IO register

ioreg - the IO register number to which to write the value

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

consumeCycle

public void consumeCycle()

The consumeCycle() method increments the cycle count of the state by one. This is generally only used internally to the simulator and tightly coupled classes, so clients of the state interface should not call this method unless they are implementing careful timings (e.g. an external RAM).

consumeCycles

public void consumeCycles(long num)

The consumeCycles() method increments the cycle count of the state by the specified number of cycles. This is generally only used internally to the simulator and tightly coupled classes, so clients of the state interface should not call this method unless they are implementing careful timings (e.g. an external RAM).

Parameters:

num - the number of cycles to advance the cycle counter

dump

public void dump()

printPair

protected final void printPair(java.lang.String n,
                               java.lang.String str,
                               boolean modified)

printPair

protected final void printPair(java.lang.String n,
                               byte val,
                               boolean modified)

printPair

protected final void printPair(java.lang.String n,
                               int val,
                               boolean modified)

printPair

protected final void printPair(java.lang.String n,
                               long val,
                               boolean modified)

clearTracingState

public void clearTracingState()