Browse Prior Art Database

Method to Provide Source Code Compatibility for Assembly Code from POWER to PowerPC

IP.com Disclosure Number: IPCOM000113881D
Original Publication Date: 1994-Oct-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 78K

Publishing Venue

IBM

Related People

Chibib, AC: AUTHOR [+4]

Abstract

Disclosed is a solution to successfully assemble an existing POWER source program, which contains POWER/PowerPC* incompatibility code, without modification to both the source program and make file. Different architecture incompatibility errors are downgraded to warnings so that the object code is still able to be generated.

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Method to Provide Source Code Compatibility for Assembly Code from
POWER to PowerPC

      Disclosed is a solution to successfully assemble an existing
POWER source program, which contains POWER/PowerPC* incompatibility
code,  without modification to both the source program and make file.
Different architecture incompatibility errors are downgraded to
warnings so that the object code is still able to be generated.

      A common  assembler is designed to support the POWER and
PowerPC architectures and implementation platforms by using  the
assembly mode  to indicate the target intention.  This feature
requires one to either change the make file to add the '-m' flag or
to change the source code to add a new pseudo op '.machine',  which
breaks the  source code compatibility.

      The reason for this is because there could be two ways to set
up the default assembly mode.  One way is to use 'RIOS/1' value as
the default value.  Although it is not required to change the
makefile or existing POWER source program, it only gets the downward
compatibility since the object code generated may not be executed in
the PowerPC architecture.  Another way is to use POWERand PowerPC
intersection as the default value.  Then a POWER source program which
has some POWER/PowerPC incompatibility codes will cause assembly
errors and assembling termination without the object code generation.
Neither way will  let the Assembler meet the both requirements for
those users who will upgrade from POWER to PowerPC and for those
users  who will remain exclusively running on POWER hardware
platforms.

      A POWER and PowerPC compatible mode in AIX V4.1 Assember is
designed to be the default mode to support the source code
compatibility.  It takes POWER/PowerPC intersection mode as its
value, i.e. it assumes that all the instructions in the source
program are available to both POWER and PowerPC architecture.  If any
err...