(thing) by yerricde Sun Apr 01 2001 at 23:27:16
A 6502 instruction that jumps to (sets the program counter to point at) an instruction stream at a given address.
  • Function: &N => PC
  • Updates flags: none
  • Opcode numbers: 
    abs   $4C (3 bytes, 3 cycles)
(a)   $6C (3 bytes, 5 cycles)

Warning about indirect JMP

Because there is no carry associated with retrieving the most significant byte of the address that a JMP (a) points to, the (a) form should NEVER have a low-order byte of $FF. For example, 

  jmp ($89ff)
will fetch the program counter from $89ff and $8900, instead of $89ff and $8a00 as expected. All other 6502 indirect addressing modes have the same "feature."

Similar: JSR
See also: 6502 instructions | 6502 addressing modes

I like it!