jfrace.cpu
Class Intel8080

java.lang.Object
  |
  +--jfrace.cpu.Intel8080

All Implemented Interfaces:

AddressSpaceListener, CPU, Hardware

Direct Known Subclasses:

Z80

public class Intel8080

extends java.lang.Object

implements AddressSpaceListener, CPU

Emulation of the 8-bit microprocessor Intel 8080. The 256 port addresses are mapped as a block to the AddressSpace. The first address (i.e. the address of port 0) is defined by the method setPortBiasAddress.

In order to increase the performance of memory reading and writing the 65536 bytes of memory will not be accessed via the AddressSpace but directly on the byte array. This memory is obtained from the first RAM added to the AddressSpace.

Note: Currently interrupts are not supported. The method next returns always 1 and not the correct number of clock cycles.

Author:

Franz-Josef Elmer

Field Summary

static int	A Index of register A (accumulator).
protected static short	ACI
protected static short	ADC
protected static short	ADD
protected static int	ADD_MASK Combined flag mask for ADD/SUB operations.
protected static short	ADI
protected static short	ANA
protected static short	ANI
protected AddressSpace	as
static int	AUX_CARRY_MASK Mask for the auxiliary carry flag.
static int	AUX_CARRY_POS Bit position of the auxiliary carry flag.
static int	B Index of register B.
static int	C Index of register C.
protected static short	CALL
static int	CARRY_MASK Mask for the carry flag.
static int	CARRY_POS Bit position of the carry flag.
protected static short	Cc
protected static short	CMA
protected static short	CMC
protected static short	CMP
protected static java.lang.String[]	CONDITION_NAMES
protected static short	CPI
static int	D Index of register D.
protected static short	DAA
protected static short	DAD
protected static java.lang.String[]	DATA_REGISTER_NAMES
protected static short	DCR
protected static short	DCX
protected static short	DI
static int	E Index of register E.
protected static short	EI
protected java.lang.String	errorDescription
static int	F Index of register F (flags).
static int	H Index of register H.
protected static short	HLT
protected static short	IN
protected static short	INR
protected static int	INR_MASK Combined flag mask for INR/DCR operations.
protected boolean	interruptEnabled
protected static short	INX
protected static short	Jc
protected static short	JMP
static int	L Index of register L.
protected static short	LDA
protected static short	LDAX
protected static short	LHLD
protected static short	LXI
protected byte[]	memory
protected static short	MOV
protected static short	MVI
protected static short	NOP
protected static byte	NULL_BYTE
protected static short[]	OP_CODE_TYPE Mapping op-code to instruction type.
protected static short	ORA
protected static short	ORI
protected static short	OUT
static int	PARITY_MASK Mask for the parity flag.
static int	PARITY_POS Bit position of the parity flag.
static int	PC Index of register PC (program counter).
protected static short	PCHL
protected static short	POP
protected int	portBiasAddress
protected int	programCounter
protected static short	PUSH
protected static short	RAL
protected static short	RAR
protected static short	Rc
protected static java.lang.String[]	REGISTER_PAIR_NAMES
protected static java.lang.String[]	REGISTER_PAIR_NAMES2
protected byte[]	registers
protected static short	RET
protected static short	RLC
protected static int	ROT_MASK Combined flag mask for ROT operations.
protected static short	RRC
protected static short	RST
protected static short	SBB
protected static short	SBI
protected static short	SHLD
static int	SIGN_MASK Mask for the sign flag.
static int	SIGN_POS Bit position of the sign flag.
static int	SP Index of register SP (stack pointer).
protected static short	SPHL
protected static short	STA
protected int	stackPointer
protected static short	STAX
protected static short	STC
protected static short	SUB
protected static short	SUI
protected static short	UDEF
protected static short	XCHG
protected static short	XRA
protected static short	XRI
protected static short	XTHL
static int	ZERO_MASK Mask for the zero flag.
static int	ZERO_POS Bit position of the zero flag.

Constructor Summary

Intel8080()
Default constructor.

Method Summary

protected void	addToAccu(byte operand, int carry, int flagMask) Add operand and carry bit to accumulator and set the flags.
protected int	calculateParityFlag(int accu) Calculate the parity flag.
protected boolean	checkCondition(byte opCode) Check condition coded in the bits 3-5 of the op-code.
int	disassemble(java.lang.StringBuffer sb, int address) Return disassemble instruction in standard Intel 8080 assembler syntax.
protected int	disassembleByte(java.lang.StringBuffer sb, int address)
protected int	disassembleUDEF(byte opCode, java.lang.StringBuffer sb, int address)
protected int	disassembleWord(java.lang.StringBuffer sb, int address)
AddressSpace	getAddressSpace() Get the address space.
java.lang.String	getErrorDescription() Return error description.
java.lang.String	getName() Return "Intel 8080".
int	getNumberOfBits() Return 8.
int	getNumberOfRegisters() Return 10.
int	getPortBiasAddress() Return the bias address for ports.
Register	getProgramCounter() Return the program counter.
Register	getRegister(int index) Return a register.
protected int	getRegisterPair(byte opCode, boolean isPopPushPair) Get the value of a register pair.
protected int	getWord(int address) Obtain a 16-bit word from the memory.
void	hardwareMoved(AddressSpaceEvent event) When a RAM is added to the AddressSpace of the CPU the memory byte array is taken from it in order to improve reading/writing performance to the memory.
void	interrupt(long interrupt) Interrupts are not supported.
int	next() Proceed one opcode.
protected int	popFromStack() Pop a 16-bit word from the stack.
protected boolean	processHLT()
protected boolean	processINRorDCR(byte opCode, int increment) Process INR and DCR commands.
protected boolean	processUDEF(byte opCode) Process an undefined op-code.
protected void	pushOnStack(int word) Push a 16-bit word onto the stack.
protected byte	readByte(int address) Read the byte from a register or from memory.
void	reset() Reset the CPU.
protected void	setAccuAndFlags(int accu, int flags) Set accumulator and flags after a bit wise.
void	setAddressSpace(AddressSpace addressSpace) Set the address space.
void	setPortBiasAddress(int address) Set the bias address for ports.
protected void	setRegisterPair(byte opCode, int value, boolean isPopPushPair) Set the value of a register pair.
void	setRegisterValue(int index, int value) Set the value of a register.
protected void	storeByte(int address, byte value) Store a byte in a register or in memory.
protected void	subtractFromAccu(byte operand, int carry, int flagMask) Subtract operand and carry from accumulator and set the flags.
boolean	supportsDisassembling() Return true.
java.lang.String	toString() Show register states like CP/M DDT.

Methods inherited from class java.lang.Object

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

Field Detail

A

public static final int A

Index of register A (accumulator).

F

public static final int F

Index of register F (flags).

B

public static final int B

Index of register B.

C

public static final int C

Index of register C.

D

public static final int D

Index of register D.

E

public static final int E

Index of register E.

H

public static final int H

Index of register H.

L

public static final int L

Index of register L.

SP

public static final int SP

Index of register SP (stack pointer).

PC

public static final int PC

Index of register PC (program counter).

SIGN_POS

public static final int SIGN_POS

Bit position of the sign flag.

ZERO_POS

public static final int ZERO_POS

Bit position of the zero flag.

AUX_CARRY_POS

public static final int AUX_CARRY_POS

Bit position of the auxiliary carry flag.

PARITY_POS

public static final int PARITY_POS

Bit position of the parity flag.

CARRY_POS

public static final int CARRY_POS

Bit position of the carry flag.

SIGN_MASK

public static final int SIGN_MASK

Mask for the sign flag.

ZERO_MASK

public static final int ZERO_MASK

Mask for the zero flag.

AUX_CARRY_MASK

public static final int AUX_CARRY_MASK

Mask for the auxiliary carry flag.

PARITY_MASK

public static final int PARITY_MASK

Mask for the parity flag.

CARRY_MASK

public static final int CARRY_MASK

Mask for the carry flag.

ADD_MASK

protected static final int ADD_MASK

Combined flag mask for ADD/SUB operations.

INR_MASK

protected static final int INR_MASK

Combined flag mask for INR/DCR operations.

ROT_MASK

protected static final int ROT_MASK

Combined flag mask for ROT operations.

DATA_REGISTER_NAMES

protected static final java.lang.String[] DATA_REGISTER_NAMES

REGISTER_PAIR_NAMES

protected static final java.lang.String[] REGISTER_PAIR_NAMES

REGISTER_PAIR_NAMES2

protected static final java.lang.String[] REGISTER_PAIR_NAMES2

CONDITION_NAMES

protected static final java.lang.String[] CONDITION_NAMES

UDEF

protected static final short UDEF

ACI

protected static final short ACI

ADC

protected static final short ADC

ADD

protected static final short ADD

ADI

protected static final short ADI

ANA

protected static final short ANA

ANI

protected static final short ANI

CALL

protected static final short CALL

Cc

protected static final short Cc

CMA

protected static final short CMA

CMC

protected static final short CMC

CMP

protected static final short CMP

CPI

protected static final short CPI

DAA

protected static final short DAA

DAD

protected static final short DAD

DCR

protected static final short DCR

DCX

protected static final short DCX

DI

protected static final short DI

EI

protected static final short EI

HLT

protected static final short HLT

IN

protected static final short IN

INR

protected static final short INR

INX

protected static final short INX

Jc

protected static final short Jc

JMP

protected static final short JMP

LDA

protected static final short LDA

LDAX

protected static final short LDAX

LHLD

protected static final short LHLD

LXI

protected static final short LXI

MOV

protected static final short MOV

MVI

protected static final short MVI

NOP

protected static final short NOP

ORA

protected static final short ORA

ORI

protected static final short ORI

OUT

protected static final short OUT

PCHL

protected static final short PCHL

POP

protected static final short POP

PUSH

protected static final short PUSH

RAL

protected static final short RAL

RAR

protected static final short RAR

Rc

protected static final short Rc

RET

protected static final short RET

RLC

protected static final short RLC

RRC

protected static final short RRC

RST

protected static final short RST

SBB

protected static final short SBB

SBI

protected static final short SBI

SHLD

protected static final short SHLD

SPHL

protected static final short SPHL

STA

protected static final short STA

STAX

protected static final short STAX

STC

protected static final short STC

SUB

protected static final short SUB

SUI

protected static final short SUI

XCHG

protected static final short XCHG

XRA

protected static final short XRA

XRI

protected static final short XRI

XTHL

protected static final short XTHL

OP_CODE_TYPE

protected static final short[] OP_CODE_TYPE

Mapping op-code to instruction type.

NULL_BYTE

protected static final byte NULL_BYTE

errorDescription

protected java.lang.String errorDescription

registers

protected byte[] registers

stackPointer

protected int stackPointer

programCounter

protected int programCounter

interruptEnabled

protected boolean interruptEnabled

as

protected AddressSpace as

memory

protected byte[] memory

portBiasAddress

protected int portBiasAddress

Constructor Detail

Intel8080

public Intel8080()

Default constructor.

Method Detail

getPortBiasAddress

public int getPortBiasAddress()

Return the bias address for ports. A 8080 port is mapped onto the address space where its address is the bias address plus the port number.

setPortBiasAddress

public void setPortBiasAddress(int address)

Set the bias address for ports. A 8080 port is mapped onto the address space where its address is the bias address plus the port number.

Parameters:

address - bias address.

toString

public java.lang.String toString()

Show register states like CP/M DDT.

Overrides:

toString in class java.lang.Object

processUDEF

protected boolean processUDEF(byte opCode)

Process an undefined op-code. Returns false. May be overwritten in subclasses.

processINRorDCR

protected boolean processINRorDCR(byte opCode,
                                  int increment)

Process INR and DCR commands.

processHLT

protected boolean processHLT()

disassembleUDEF

protected int disassembleUDEF(byte opCode,
                              java.lang.StringBuffer sb,
                              int address)

disassembleByte

protected int disassembleByte(java.lang.StringBuffer sb,
                              int address)

disassembleWord

protected int disassembleWord(java.lang.StringBuffer sb,
                              int address)

readByte

protected byte readByte(int address)

Read the byte from a register or from memory. The list shows the mapping between registers and address code:

Register	Address code
B	0
C	1
D	2
E	3
H	4
L	5
Memory	6
A	7

The memory address is given by the register pair HL.

Parameters:

address - address code.

Returns:

the read byte

storeByte

protected void storeByte(int address,
                         byte value)

Store a byte in a register or in memory. The list shows the mapping between registers and address code:

Register	Address code
B	0
C	1
D	2
E	3
H	4
L	5
Memory	6
A	7

The memory address is given by the register pair HL.

Parameters:

address - address code.

value - value to be stored.

getRegisterPair

protected int getRegisterPair(byte opCode,
                              boolean isPopPushPair)

Get the value of a register pair.

Op-code pattern	Register pair
xx00xxxx	BC
xx01xxxx	DE
xx10xxxx	HL
xx11xxxx	AF if isPopPushPair == true SP if isPopPushPair == false

Parameters:

opCode - op-code.

isPopPushPair - true if a register pair is meant for a POP or PUSH command.

Returns:

a word.

setRegisterPair

protected void setRegisterPair(byte opCode,
                               int value,
                               boolean isPopPushPair)

Set the value of a register pair.

Op-code pattern	Register pair
xx00xxxx	BC
xx01xxxx	DE
xx10xxxx	HL
xx11xxxx	AF if isPopPushPair == true SP if isPopPushPair == false

Parameters:

opCode - op-code.

value - value of the pair..

isPopPushPair - true if a register pair is meant for a POP or PUSH command.

getWord

protected int getWord(int address)

Obtain a 16-bit word from the memory. Assume lower order bit first.

Parameters:

address - memory address.

Returns:

word.

pushOnStack

protected void pushOnStack(int word)

Push a 16-bit word onto the stack. The high byte will be stored in stackPointer - 1 and the low byte in stackPointer - 2. The stack pointer will be decreased by two.

Parameters:

word - word to be push onto the stack.

popFromStack

protected int popFromStack()

Pop a 16-bit word from the stack. The low byte will be read from stackPointer and the high byte in stackPointer + 1. The stack pointer will be increased by two.

Returns:

poped word.

checkCondition

protected boolean checkCondition(byte opCode)

Check condition coded in the bits 3-5 of the op-code.

Op-code pattern	Condition
xx000xxx NZ	zeroFlag == false
xx001xxx Z	zeroFlag == true
xx010xxx NC	carryFlag == false
xx011xxx C	carryFlag == true
xx100xxx PO	parityFlag == false
xx101xxx PE	parityFlag == true
xx110xxx P	signFlag == false
xx111xxx M	signFlag == true

Parameters:

opCode - op-code.

Returns:

true if the condition is fulfilled.

addToAccu

protected void addToAccu(byte operand,
                         int carry,
                         int flagMask)

Add operand and carry bit to accumulator and set the flags.

subtractFromAccu

protected void subtractFromAccu(byte operand,
                                int carry,
                                int flagMask)

Subtract operand and carry from accumulator and set the flags.

setAccuAndFlags

protected void setAccuAndFlags(int accu,
                               int flags)

Set accumulator and flags after a bit wise.

Parameters:

accu - result of the bit wise operation.

flags - initial flags set.

calculateParityFlag

protected int calculateParityFlag(int accu)

Calculate the parity flag. Return PARITY_MASK if there is an even number of bits set in the lowest order byte of accu.

Returns:

PARITY_MASK if an even number bits of the accumulator have the value 1. Otherwise 0 is returned.

hardwareMoved

public void hardwareMoved(AddressSpaceEvent event)

When a RAM is added to the AddressSpace of the CPU the memory byte array is taken from it in order to improve reading/writing performance to the memory.

Specified by:

hardwareMoved in interface AddressSpaceListener

Following copied from interface: jfrace.AddressSpaceListener

Parameters:

event - Event holding the details.

getName

public java.lang.String getName()

Return "Intel 8080".

Specified by:

getName in interface CPU

getNumberOfBits

public int getNumberOfBits()

Return 8.

Specified by:

getNumberOfBits in interface Hardware

getNumberOfRegisters

public int getNumberOfRegisters()

Return 10.

Specified by:

getNumberOfRegisters in interface CPU

getRegister

public Register getRegister(int index)

Description copied from interface: CPU

Return a register.

Specified by:

getRegister in interface CPU

Following copied from interface: jfrace.CPU

Parameters:

index - Index of the register.

Returns:

null if no register exists for the given index.

getProgramCounter

public Register getProgramCounter()

Description copied from interface: CPU

Return the program counter. The program counter is a special register.

Specified by:

getProgramCounter in interface CPU

setRegisterValue

public void setRegisterValue(int index,
                             int value)

Description copied from interface: CPU

Set the value of a register.

Specified by:

setRegisterValue in interface CPU

Following copied from interface: jfrace.CPU

Parameters:

index - Index of the register.

value - New value.

setAddressSpace

public void setAddressSpace(AddressSpace addressSpace)

Set the address space. Looks for already existing RAM. If one found it takes the corresponding memory array.

Specified by:

setAddressSpace in interface CPU

getAddressSpace

public AddressSpace getAddressSpace()

Description copied from interface: CPU

Get the address space.

Specified by:

getAddressSpace in interface CPU

reset

public void reset()

Reset the CPU. The internal state will be set into a well-defined initial state.

Specified by:

reset in interface Hardware

interrupt

public void interrupt(long interrupt)

Interrupts are not supported.

Specified by:

interrupt in interface CPU

Following copied from interface: jfrace.CPU

Parameters:

interrupt - Bit pattern of the interrupt. The meaning of the bits depend on the implementation.

getErrorDescription

public java.lang.String getErrorDescription()

Return error description. The meaning of the error code depends on the implementation. This method should be called when next() return false.

Specified by:

getErrorDescription in interface CPU

Returns:

an empty string if no error occured.

next

public int next()

Proceed one opcode.

Specified by:

next in interface CPU

Returns:

always 1 excepted in the case of an error.

supportsDisassembling

public boolean supportsDisassembling()

Return true.

Specified by:

supportsDisassembling in interface CPU

disassemble

public int disassemble(java.lang.StringBuffer sb,
                       int address)

Return disassemble instruction in standard Intel 8080 assembler syntax.

Specified by:

disassemble in interface CPU

Following copied from interface: jfrace.CPU

Parameters:

sb - String buffer.

address - Address of op-code.

Returns:

number of addressable units of the op-code at address.