Changes
MOS 6502
,/* Oddities */
== Oddities ==
* The 6502 divides each clock cycle into two phases (ϕ1 and ϕ2). The use of half-cycles ensures that memory and I/O devices have predictable timing windows when the CPU will access the bus, while still allowing the CPU to perform internal operations in parallel.
* The decimal mode flag in the processor status register is unchanged following an interrupt of any kind. This behavior can potentially result in a difficult to locate bug in the interrupt handler if decimal mode happens to be enabled at the time of an interrupt.