wiki:WritingRules/General

Version 4 (modified by Nicolas Pouillon, 17 years ago) (diff)

Formatting, typos, cosmetic changes

General rules for the SoCLib hardware components

Naming conventions

Namespaces

SystemC being build upon C++, we use the C++ namespace constructs, to create unambiguous names. SoCLib defines the following namespaces:

  • soclib
  • soclib::common
  • soclib::caba
  • soclib::tlmt

Variables

The following conventions have been defined :

  • All component port names should be prefixed with p_
  • All component register names should be prefixed with r_
  • All component member variable names should be prefixed with m_

VCI initiators and targets indexation

In a VCI-based architecture, all initiators and targets must be indexed. Initiators and targets have different address spaces.

  • The target index is used by interconnect components to route the VCI command packets : the target index is decoded from VCI ADDRESS MSBs.
  • The initiator index is used by the interconnect components to route the VCI response packets : the initiator index is the VCI RSRCID.

Indexes can be :

  • a simple scalar index, in case of a flat interconnect.
  • a composite index, in case of a clusterised architecture, using a two-level (or more) hierarchical interconnect.

include/common/int_tab.h defines an utility class storing a list of indexes.

All indexes must be declared as IntTabs.

Endianness

All SoCLib targets components are little-endian. In case of write, the bytes positions are fully controlled by the VCI BE bits :

  • LSBs of the VCI ADDRESS are ignored, and the VCI ADDRESS is only used to select a VCI cell (a word in memory).
  • Bytes are selected by the VCI BE field, and the BE[0] bit is always associated to the Byte 0 of the VCI WDATA field (ie WDATA[7:0]).