Package io.matita08.logic

Enum Class Operations4Bit

java.lang.Object

java.lang.Enum<Operations4Bit>

io.matita08.logic.Operations4Bit

All Implemented Interfaces:

Serializable, Comparable<Operations4Bit>, Constable

public enum Operations4Bit
extends Enum<Operations4Bit>

4-Bit CPU Instruction Set Implementation. This enum defines a more comprehensive instruction set for a 4-bit CPU architecture, implementing extended operations including subtraction, unconditional jumps, and additional conditional branching capabilities.

Extended Instruction Set:

• LOAD (0) - Load value from memory address to accumulator
• STO (1) - Store accumulator to memory address
• SET (2) - Copy accumulator value to RegB
• IN (3) - Input value from input buffer to accumulator
• OUT (4) - Output accumulator value to output buffer
• ADD (5) - Add RegB to accumulator
• SUB (6) - Subtract RegB from accumulator
• JMP (7) - Unconditional jump to address
• JPZ (8) - Jump to address if zero flag is set
• JPO (9) - Jump to address if overflow flag is set
• HALT (15) - Stop CPU execution

This instruction set provides enhanced control flow capabilities compared to the 3-bit version, including unconditional jumps and overflow-based conditional branching.

Note: This is an alternative instruction set that can be selected via command-line arguments. Many operations are currently implemented as stubs and require completion for full functionality.

Since:

1.0

See Also:

• Operations3Bit
• Operation

Nested Class Summary

Nested classes/interfaces inherited from class java.lang.Enum

Enum.EnumDesc<E extends Enum<E>>

Enum Constant Summary

Enum Constants

Enum Constant	Description
add	ADD (Addition) - Opcode 5.
Halt	HALT (Halt Execution) - Opcode 15.
in	IN (Input) - Opcode 3.
jmp	JMP (Unconditional Jump) - Opcode 7.
jpo	JPO (Jump if Overflow) - Opcode 9.
jpz	JPZ (Jump if Zero) - Opcode 8.
load	LOAD (Load) - Opcode 0.
out	OUT (Output) - Opcode 4.
set	SET (Set Register B) - Opcode 2.
sto	STO (Store) - Opcode 1.
sub	SUB (Subtraction) - Opcode 6.
Unknown	UNKNOWN (Invalid Opcode Handler) - Opcode 16.

Field Summary

Fields

Modifier and Type	Field	Description
static final Operations4Bit[]	all	Array containing all available operations in this instruction set.
final Operation	wrapper	The Operation wrapper object that provides the execution interface.

Method Summary

Modifier and Type	Method	Description
static Operation	getHalt()	Gets the HALT operation for CPU termination.
static Operation	getUnknown()	Gets the UNKNOWN operation for invalid opcodes.
static Operations4Bit	valueOf(String name)	Returns the enum constant of this class with the specified name.
static Operations4Bit[]	values()	Returns an array containing the constants of this enum class, in the order they are declared.

Methods inherited from class java.lang.Enum

clone, compareTo, describeConstable, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Enum Constant Details

load

public static final Operations4Bit load

LOAD (Load) - Opcode 0. Loads a value from the memory address specified by the pointer register into the accumulator. This is a multi-cycle operation.

Status: Stub implementation - requires completion

Execution cycles: 2

sto

public static final Operations4Bit sto

STO (Store) - Opcode 1. Stores the current accumulator value to the memory address specified by the pointer register. This is a multi-cycle operation.

Status: Stub implementation - requires completion

Execution cycles: 2

set

public static final Operations4Bit set

SET (Set Register B) - Opcode 2. Copies the current accumulator value to RegB. This is typically used to prepare operands for arithmetic operations.

Execution cycles: 1 (single-cycle operation)

in

public static final Operations4Bit in

IN (Input) - Opcode 3. Copies the current input buffer value to the accumulator register. This provides the interface between input devices and the CPU.

Status: Stub implementation - requires completion

Execution cycles: 1 (single-cycle operation)

out

public static final Operations4Bit out

OUT (Output) - Opcode 4. Copies the current accumulator value to the output buffer register. This provides the interface between the CPU and output devices.

Status: Stub implementation - requires completion

Execution cycles: 1 (single-cycle operation)

add

public static final Operations4Bit add

ADD (Addition) - Opcode 5. Performs arithmetic addition of the accumulator and RegB, storing the result in the accumulator. Should update CPU flags.

Status: Stub implementation - requires completion

Execution cycles: 1 (single-cycle operation)

sub

public static final Operations4Bit sub

SUB (Subtraction) - Opcode 6. Performs arithmetic subtraction of RegB from the accumulator, storing the result in the accumulator. Should update CPU flags.

Status: Stub implementation - requires completion

Execution cycles: 1 (single-cycle operation)

jmp

public static final Operations4Bit jmp

JMP (Unconditional Jump) - Opcode 7. Unconditionally jumps to the address specified by the pointer register. This is a multi-cycle operation that reads the target address then jumps.

Execution logic:

• Cycle 2: Read target address from memory into pointer
• Cycle 1: Set PC to pointer value

Execution cycles: 2

jpz

public static final Operations4Bit jpz

JPZ (Jump if Zero) - Opcode 8. Conditional jump instruction that jumps to the specified address if the Zero flag is set. If the flag is not set, execution continues with the next instruction.

Status: Stub implementation - requires completion

Execution cycles: 1

jpo

public static final Operations4Bit jpo

JPO (Jump if Overflow) - Opcode 9. Conditional jump instruction that jumps to the specified address if the Overflow flag is set. If the flag is not set, execution continues with the next instruction.

Status: Stub implementation - requires completion

Execution cycles: 1

Halt

public static final Operations4Bit Halt

HALT (Halt Execution) - Opcode 15. Stops CPU execution. This instruction causes the CPU to enter a halted state where no further instructions are processed.

Execution cycles: 1 (single-cycle operation)

Unknown

public static final Operations4Bit Unknown

UNKNOWN (Invalid Opcode Handler) - Opcode 16. Special operation used as a fallback for invalid or unrecognized opcodes. Provides graceful handling of instruction decode errors.

Field Details

all

public static final Operations4Bit[] all

Array containing all available operations in this instruction set.

wrapper

public final Operation wrapper

The Operation wrapper object that provides the execution interface.

Method Details

values

public static Operations4Bit[] values()

Returns an array containing the constants of this enum class, in the order they are declared.

Returns:

an array containing the constants of this enum class, in the order they are declared

valueOf

public static Operations4Bit valueOf(String name)

Returns the enum constant of this class with the specified name. The string must match exactly an identifier used to declare an enum constant in this class. (Extraneous whitespace characters are not permitted.)

Parameters:

name - the name of the enum constant to be returned.

Returns:

the enum constant with the specified name

Throws:

IllegalArgumentException - if this enum class has no constant with the specified name

NullPointerException - if the argument is null

getHalt

public static Operation getHalt()

Gets the HALT operation for CPU termination. Used by the Operation class during dynamic loading to identify the halt instruction.

Returns:

the HALT operation wrapper

getUnknown

public static Operation getUnknown()

Gets the UNKNOWN operation for invalid opcodes. Used by the Operation class during dynamic loading to handle unrecognized instruction codes.

Returns:

the UNKNOWN operation wrapper