This is the mail archive of the guile@cygnus.com mailing list for the guile project.
| Index Nav: | [Date Index] [Subject Index] [Author Index] [Thread Index] | |
|---|---|---|
| Message Nav: | [Date Prev] [Date Next] | [Thread Prev] [Thread Next] |
> I ran t.c through all the compilers I could find (HP-UX, SOLARIS, > Digital UNIX, AIX, Visual C++); they all generated arithmetic > right shifts for the signed long value. Did the standard get > amended somewhere along the line? The reason this is implementation-defined is because the concept of "sign-extension" is implementation-defined. For example, it is not clear what it would mean on a system using signed-magnitude representation of integers. But since all modern hardware uses 2's complement, and since all reasonable compilers implement sign extension, in practice right shift is is portable and well-defined. One data point: Java, which specifies a 2's complement representation, does specify sign extension. --Per Bothner Cygnus Solutions bothner@cygnus.com http://www.cygnus.com/~bothner