PALcode(Privileged Architecture Library code)[1][2]is the name used by DEC in theAlphainstruction set architecture(ISA) for a set of functions in theSystem Reference Manual(SRM) orAlphaBIOSfirmware,providing ahardware abstraction layerfor system software, covering features such as cache management,translation lookaside buffer(TLB) miss handling, interrupt handling, and exception handling. It evolved from a feature of theDEC PRISMarchitecture named Epicode.[3]
PALcode is Alpha machine code, running in a special mode[4]that also allows access to internal registers specific to the particular Alpha processor implementation. Thus, it is somewhere between the role ofmicrocodeand of a hardwareemulator.PALcode isoperating system-specific,[5]so different versions of PALcode are required byOpenVMS,Tru64 UNIX,andWindows NT.Tru64 UNIX PALcode is also used byNetBSD,FreeBSD,OpenBSDandLinux.
References
edit- ^Alpha Architecture Reference Manual.2014.ISBN978-1483294339.
PALcode—Alpha's Very Flexible Privileged Software Library A Privileged Architecture Library (PALcode) is a set of subroutines that...
- ^"PALcode for Alpha Microprocessors System Design Guide"(PDF).May 2, 1996.
PALcode for Alpha Microprocessors. System Design Guide. May 1996. This guide explains how to use the Privileged Architecture Library code.
- ^Neil Rieck."Dave Cutler, PRISM, Mica, Emerald, etc".neilrieck.net.Retrieved2020-12-21.
- ^"PALcode - ES40 Emulator".
PALcode is Alpha machine code, running in a special mode that allows access to internal registers specific to the particular Alpha processor
- ^"The Alpha AXP Processor".
The Alpha AXP architecture uses a set of subroutines, call privileged architecture library code (PALcode). PALcode is specific to the operating system, the CPU...
External links
edit- Hewlett Packard OpenVMS FAQ(archived on May 11, 2011)
- "PALcode for Alpha Microprocessors System Design Guide"(PDF).Digital Equipment Corporation.May 1996.RetrievedNovember 7,2013.
- Bruce Hutton."Some simple PAL code".Archived fromthe originalon July 13, 2015.
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