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@@ -16,6 +16,21 @@ Registers store data which can be accessed at any time. These include special re | `fp` | 64 bits | Frame pointer | | `ptp` | 64 bits | Page tree pointer | +## Link Registers + +The link registers are for storing specific return addresses from a subroutine + +| Name | Size | Purpose | +| ---------- | -------- | --------------------------- +| `blr` | 64 bits | Branch Link Register | +| `ilr` | 64 bits | Interrupt Link Register | + +When calling a subroutine, it will need to know where to return to +when the execution finishes. To achieve this, we use the branch link +register (BLR). In situations where an interrupt has occurred on the +system, the CPU would need to know where to return to from the interrupt +context, in cases such as this, we'd use the Interrupt Link Register (ILR). + ### Internal Registers Only accessed by the CPU for certain instructions. Cannot be directly read/written. |