6502-Emulator

This is an emulator for a 6502 Processor coded in C++

Working functions

• LDA - Load memory into A registry
• LDX - Load memory into X registry
• LDY - Load memory into Y registry
• STA - Store the value from A registry into a memory address
• STX - Store the value from X registry into a memory address
• STY - Store the value from Y registry into a memory address
• JSR - Jump to a subroutine
• TAX - Transfer A to X
• TAY - Transfer A to Y
• TXA - Transfer X to A
• TYA - Transfer Y to A
• TSX - Transfer stackpointer to X
• TXS - Transfer X to stackpointer
• PHA - Push A to stack
• PLA - Pull A from stack
• INX - Increment X
• INY - Increment Y
• DEX - Decrement X
• DEY - Decrement Y
• NOP - No operation
• RTS - Return from subroutine
• SEC - Set carry flag
• SED - Set decimal mode
• SEI - Set interrupt disable
• CLC - Clear carry flag
• CLD - Clear decimal mode
• CLI - Clear interrupt disable
• CLV - Clear overflow flag
• AND - Logical AND
• DEC - Decrement memory
• INC - Increment memory
• ASL - Arithmetic bit wise shift left
• LSR - Logical shift right
• ORA - Logical inclusive OR
• JMP - Jump

Operation codes as words

To run a program you might use the words below in the separate file called program.xndr in the same directory

• ldaim - Load Accumulator | Immediate
• ldazp - Load Accumulator | Zero Page
• ldazpx - Load Accumulator | Zero Page X
• ldxim - Load X | Immediate
• ldxzp - Load X | Zero Page
• ldxzpy - Load X | Zero Page Y
• ldyim - Load Y | Immediate
• ldyzp - Load Y | Zero Page
• ldyzpx - Load Y | Zero Page X
• sta - Store Accumulator | Zero Page
• stax - Store Accumulator | Zero Page X
• stx - Store X | Zero Page
• stxy - Store X | Zero Page Y
• sty - Store Y | Zero Page
• styx - Store Y | Zero Page X
• tax - Transfer Accumulator into X
• tay - Transfer Accumulator into Y
• txa - Transfer X into Accumulator
• tya - Transfer Y into Accumulator
• tsx - Transfer stack pointer into X
• txs - Transfer X into stack pointer
• pha - Push Accumulator on stack
• pla - Pull Accumulator from stack
• inx - Increment X
• iny - Increment Y
• dex - Decrement X
• dey - Decrement Y
• nop - No operation
• rts - Return from subroutine
• sec - Set carry flag
• sed - Set decimal flag
• sei - Set interrupt flag
• clc - Clear carry flag
• cld - Clear decimal flag
• cli - Clear interrupt flag
• clv - Clear overflow flag
• and - Logical AND | Immediate
• andzp - Logical AND | Zero Page
• andzpx - Logical AND | Zero Page X
• dec - Decrement | Zero Page
• decx - Decrement | Zero Page X
• inc - Increment | Zero Page
• incx - Increment | Zero Page X
• asl - Arithmetic bit wise shift left | Immediate
• aslzp - Arithmetic bit wise shift left | Zero Page
• aslzpx - Arithmetic bit wise shift left | Zero Page X
• lsr - Logical shift right | Immediate
• lsrzp - Logical shift right | Zero Page
• lsrzpx - Logical shift right | Zero Page X
• or - Logical inclusive OR | Immediate
• orzp - Logical inclusive OR | Zero Page
• orzpx - Logical inclusive OR | Zero Page X
• jmp - Jump | Absolute
• jsr - Jump to subroutine

Example:

ldaim
25
ldxim
35
dex

=>

a: 25
x: 34
y: 0

Addresses and numbers have to be in Base 10 Every operation, argument or address has to be on his own line

Every unknown operation results in a nop, except if it's a number/address