User manual APOGEE SOFTWARE APOGEE COMPILERS C & C++ & FORTRAN 77 & FORTRAN 90

[. . . ] USER'S MANUAL rs FOR e COMPILERS VAPOGEE APOGEE-CTM APOGEE-C++TM n io HIGHLY OPTIMIZING COMPILERS WITH INTRODUCTION TO KAPTM & VASTTM PREPROCESSORS & FLEXLMTM LICENSE MANAGER 4. 0 APOGEE-FORTRAN 77TM APOGEE-FORTRAN 90TM © 1990-1996 -- Apogee Software, Inc. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the express written permission of Apogee Software, Inc. Information in this document is subject to change without notice and does not represent a commitment on the part of Apogee Software, Inc. The software described in this document is furnished under a license and may be used or copied only in accordance with the terms of such license. [. . . ] 5) For a double word value parameter, if there is an even number of words counted to its left (where 0 is even), then it is misaligned on the stack. Compilers face two different kinds of situations in compiling memory references in a program: · Direct references. When a memory object is referenced directly, via its declared name, its memory layout is known, and thus its alignment/misalignment properties are known. In this case, the compiler can generate the appropriate accessing instructions. When a memory object is referenced indirectly, via a run-time pointer value, its memory layout is unknown, and thus its alignment/misalignment properties are unknown. In this case the compiler must use "worst case" assumptions to generate accessing instructions. · Examples of direct references are references to variables via their own names, and references to C parameters via the parameter name. Examples of indirect references are use of the C dereference operator (*) and references to FORTRAN formal parameter names. The dilemma for the compiler is what kind of accessing instructions to compile for indirect references to double word objects. If single-word instructions are used, the program will run properly when misaligned objects are present, but the performance of the program will be negatively impacted. In fact, if there are indirect references to double-word objects in an important loop, there may be a significant slowdown. On the other hand, if double-word instructions are used, the performance will not be impacted, but legal programs may fail. This choice of accessing instructions for indirectly referenced double-word objects is governed by the alnref control-variable. Specifically: -Xalnref=0 Assume that double-word objects referred to indirectly will always be properly aligned, so double-word load and store instructions can be used. Assume that double-word objects referred to indirectly may be misaligned, so double-word load and store instructions can not be used. -Xalnref=1 The important practical fact about this choice is that only a very few programs will fail if alnref=0 mode used. For this failure to occur, there must first be a misaligned object, and then it must be referred to indirectly. Some examples of how this could occur are as follows: · · · In FORTRAN, in alnstd=1 mode, a misaligned double-word object might be passed as an argument to a subroutine, and then referenced in that subroutine. In C, an argument to a subroutine is misaligned on the stack, and then its address is taken and later dereferenced. In mixed C and FORTRAN, an argument to a C routine is misaligned on the stack, and then its address is taken and passed to a FORTRAN subroutine as a reference parameter which is then referenced. Apogee User's Manual Page 91 Apogee Software, Inc. · In mixed C and FORTRAN, in alnstd=1 mode for the FORTRAN routine, a misaligned double-word object is passed as an argument to a C routine, which is then dereferenced. Notice that in pure FORTRAN (because there are no value parameters), unless the alnstd=1 mode is used, failure will never occur. Also notice that even in C, failure is not likely, since even if a routine is passed a double, it is not common to refer to such numeric parameters via a pointer. The alnref control-variable has routine scope and accepts values of 0 and 1. Both the firstdefault-value and second-default value are alnref=1. The -dalign command line option is an abbreviation for -Xalnref=0. Control-Variable bss -- Use of . bss section Data items that do not require link-time initialization to specific non-zero values may be placed in either the . data or . bss section. [. . . ] Solution: You may not modify the license-file (except for the specified fields described above). If you need to change something in your license-file, you must get a new license from your software vendor. Symptom: When I start up lmgrd, it says "excl failed" on my vendor daemon. Cause: lmgrd uses excl to start each vendor daemon running. [. . . ]