Intel C2518 FH8065501516710 Data Sheet

Intel

®

 Atom™ Processor C2000 Product Family for Microserver

September 2014

Datasheet, Vol. 2 of 3

Order Number: 330061-002US

223

This involves a single PCIe agent targeting a location in the memory space and 

performs a read-modify-write sequence to the location. This technology is supported by 

the root ports, but not for peer-to-peer transactions.

With PCI Express Atomic Operations (AtomicOps), a PCIe agent performs a single PCI 

Express transaction targeting a location in memory address space which:

1. Reads the memory location data value.
2. Potentially writes a new value to the data location.
3. Returns the original value.

PCIe Atomic Operations (AtomicOps):

• Fetch and Add (FetchAdd) - The value of a target location is incremented by a 

specified value using two’s complement arithmetic, ignoring any carry or overflow, 

and the result is written back to the location. The original location value is 

returned.

• Unconditional Swap (Swap) - A specified value is written to a target location, and 

the original location value is returned.

• Compare and Swap (CAS) - The value of a target location is compared to a 

specified value and, if they match, another specified value is written back to the 

location. Regardless whether they match, the original location value is returned.

Conforming with the PCI Express Base Specification, Revision 2.1, the FetchAdd and 

Swap operations each has one operand. Operand sizes of 32 and 64 bits are supported. 

The CAS operation has two operands and supports operand sizes of 32, 64, and 128 

bits.