6502 stack instructions

6502 Subroutine Instructions • JSR: Jump to subroutine • RTS: Return from subroutine Philipp Koehn Computer Systems Fundamentals: 6502 Stack

6502 Instruction Encoding group mode opcode group mode to save registers on the stack, but the 6502's cramped (256 byte) stack demands parsimony 

Including the 6502, 65C02 and 65802 6502/65C02 Addressing Modes on the 65816 FIGURE 14-1 STACK SNAPSHOT AFTER PEI (12) INSTRUCTION

6502 Processor Instruction Set Load and Store Group Mnemônico Operação Push processor status on stack PHP $08 1 none PLA Pull accumulator from 

Pull accumulator from stack N,Z PLP Pull processor status from stack All Status Flag Change Group CLC Clear carry flag C CLD Clear decimal mode flag D

of 6502 instructions They are used to transfer the contents of the X and Y registers with the A register, and between X and the stack pointer (S) In table form:

In a few processors such as the 6502, instructions that reference primary memory have unlimited access to every byte in that memory The 6502 has a 64K 

The JSR (Jump to Subroutine) instruction saves the address of its own third byte in the stack, that is, JSR saves the return address minus 1 RTS (Return from 

especially when the activity involves coding Assembly Language instructions Only by actually This is how a 6502 memory stack works It is a handy tool in

Variable Length Stack Interrupt Capability • Non-maskable Interrupt Use with Any Type or Speed Memory • Bi-directional Data Bus • Instruction Decoding and