6502 emulator.

!!!!!!! Not baked yet !!!!!!!

---> This is custom 6502 emulator. <---

6502 Emulator Memory Map

---

📦 Full Memory Layout

Address Range	Size	Description
$0000 – $00FF	256 bytes	Zero Page
$0100 – $01FF	256 bytes	Stack (used by Stack Pointer)
$0200 – $05FF	1024 bytes	Pixel Display Memory
$0600 – $0601	2 bytes	LED Display (16 LEDs total)
$0602 – $0605	4 bytes	7-Segment HEX Display (4 digits)
$0606	2 bytes	Switch Panel (10 bits + "All")
$0608+	Reserved	(Push buttons / IRQs / Future I/O)
$0700 – $7FFF	Free / RAM	General purpose RAM or programs
$8000 – $FFFF	32KB	ROM / Cartridge / Program Code

---

🔌 I/O Devices ($0600 and up)

Address	Device	Description
$0600	LED Lower Byte	LEDs 0–7 (1 bit each)
$0601	LED Upper Byte	LEDs 8–15 (1 bit each)
$0602 – $0605	HEX 7-Segment Display	4 digits, 1 byte per digit (0x0–0xF)
$0606	Switches	10-bit toggle switches (bits 0–9)
$0607	(Reserved)	Reserved / Padding
$0608+	Future I/O	Push buttons, interrupts, etc. (planned)

---

📦 CPU Registers

Name	Full Name	Size	Description
PC	Program Counter	16-bit	Points to the next instruction
AC	Accumulator	8-bit	Used for arithmetic and logic ops
X	X Register	8-bit	General-purpose / indexing
Y	Y Register	8-bit	General-purpose / indexing
SR	Status Register	8-bit	Processor flags: N V - B D I Z C
SP	Stack Pointer	8-bit	Stack offset from $0100 base

📦 Instruction set

Not all instructions are implemented in current stage

Mnemonic	Description
ADC	Add with carry
AND	And (with accumulator)
ASL	Arithmetic shift left
BCC	Branch on carry clear
BCS	Branch on carry set
BEQ	Branch on equal (zero set)
BIT	Bit test
BMI	Branch on minus (negative set)
BNE	Branch on not equal (zero clear)
BPL	Branch on plus (negative clear)
BRK	Break / interrupt
BVC	Branch on overflow clear
BVS	Branch on overflow set
CLC	Clear carry
CLD	Clear decimal
CLI	Clear interrupt disable
CLV	Clear overflow
CMP	Compare (with accumulator)
CPX	Compare with X
CPY	Compare with Y
DEC	Decrement
DEX	Decrement X
DEY	Decrement Y
EOR	Exclusive OR (with accumulator)
INC	Increment
INX	Increment X
INY	Increment Y
JMP	Jump
JSR	Jump subroutine
LDA	Load accumulator
LDX	Load X
LDY	Load Y
LSR	Logical shift right
NOP	No operation
ORA	OR with accumulator
PHA	Push accumulator
PHP	Push processor status (SR)
PLA	Pull accumulator
PLP	Pull processor status (SR)
ROL	Rotate left
ROR	Rotate right
RTI	Return from interrupt
RTS	Return from subroutine
SBC	Subtract with carry
SEC	Set carry
SED	Set decimal
SEI	Set interrupt disable
STA	Store accumulator
STX	Store X
STY	Store Y
TAX	Transfer accumulator to X
TAY	Transfer accumulator to Y
TSX	Transfer stack pointer to X
TXA	Transfer X to accumulator
TXS	Transfer X to stack pointer
TYA	Transfer Y to accumulator

📦 Number Notation

Notation	Example	Meaning
$	$20	Hexadecimal (base 16)
%	%10101010	Binary (base 2)
#	#$20	Immediate value (literal byte)
Decimal	42	Interpreted as decimal
'A'	'A'	ASCII character → byte value

---

📦 6502 Addressing Modes (with Examples)

Mode	Syntax	Example	Description
Immediate	#value	LDA #$01	Load literal value directly
Zero Page	addr	LDA $10	Load from zero page address ($0000–$00FF)
Zero Page,X	addr,X	LDA $10,X	Zero page address + X register
Zero Page,Y	addr,Y	LDX $10,Y	Zero page address + Y register
Absolute	addr	LDA $1234	Load from 16-bit address
Absolute,X	addr,X	LDA $1234,X	Absolute address offset by X
Absolute,Y	addr,Y	LDA $1234,Y	Absolute address offset by Y
Indirect	(addr)	JMP ($1234)	Jump to address stored at address (used only with JMP)
Indexed Indirect	(addr,X)	LDA ($20,X)	Add X to zero page address, then load from resulting address
Indirect Indexed	(addr),Y	LDA ($20),Y	Read address from zero page, then add Y offset
Accumulator	(implicit)	ASL	Operates directly on accumulator (A)
Implied	(no operand)	CLC	Instruction has no operand
Relative	(label/offset)	BEQ label	Used with branches (offset from PC)

---