I think I see your problem. Try compiling with LANGLVL(LONGLONG). On 22/07/2013, at 12:17 PM, Charles Mills <charl...@mcn.org> wrote:
> Perhaps more to the point, here are my exact options, minus only some > comments: > > TARG(LE,zOSV1R9) > # On 1/10/11 Xxxxx Yyyyy wrote that Zzzzz was on z990s > ARCH(6) > # Force most enums to be integers for consistency > ENUMSIZ(INT) > # Test of several optimization options > AGGRCOPY HGPR LIBANSI > # Some new optimization -- suspect these if problem! > ROCONST > # TEST Seems to hose up the linker if CSECT also specified > # Uncomment to show macros -- *** V1R13 and above *** > # SHOWM LIST PPONLY > # Try suppressing the multi-character literal warning for Events > SUPP(CCN5802) > # NODLL may be necessary to make the program COBOL-loadable > NODLL > # XPL(OSCALL(U)) OBJECTMODEL(IBM) > # Set the following based on optimization desired > # 0 and NOINLINE TEST or 2 and INLINE NOTEST > # OPT(0) NOINLINE TEST GONUMBER > OPT(2) INLINE NOTEST NOGONUMBER COMPRESS > # Turn on the LIST option - "pseudo-assembler" listing > # LIST > # Experiment for XXXXXXXX - does not seem to hurt anything > DLL(CBA) > > Charles > > -----Original Message----- > From: IBM Mainframe Discussion List [mailto:IBM-MAIN@LISTSERV.UA.EDU] On > Behalf Of Charles Mills > Sent: Sunday, July 21, 2013 8:57 PM > To: IBM-MAIN@LISTSERV.UA.EDU > Subject: Re: Looking for help with an obscure C integer problem > > Here is exact cut and paste with zero editing, complete with a typo in the > second comment. The code is unit tested on MS Visual Studio -- hence the two > #ifdef's. > > // Find First Set > static inline int Ffs64(unsigned long long valueToTest) > { > // returns index of first set bit. Uses UNIX convention > where bit 1 is LSB of word for compatibilit with z/OS ffs() > > static const unsigned long long lswMask = > 0x00000000ffffffff; > > // note Windows provides a _BitScanForward64() but I did it > this way to make it more z/OS-like for test purposes > // if we ever needed Windows efficiency, or if IBM provides > an ffs64(), then this should be re-written to take advantage > > if ( valueToTest == 0 ) return 0; > > unsigned int testWord; > testWord = valueToTest & lswMask; > if ( testWord != 0 ) > { > // _BitScanForward returns base 0 > #ifdef WIN32 > unsigned long index; > _BitScanForward(&index, testWord); > return index+1; > #else > return ffs(testWord); > #endif > } > else > { > testWord = valueToTest >> 32; > #ifdef WIN32 > unsigned long index; > _BitScanForward(&index, testWord); > return index+33; > #else > return ffs(testWord) + 32; > #endif > > } > } > > I have strong -- but not utterly conclusive; you know what debugging a > complex program is like -- that for the value I had in the OP -- > 0x0034000000000000? -- the method returns 32, implying that the final ffs() > was called with testWord = 0. > > Charles > > -----Original Message----- > From: IBM Mainframe Discussion List [mailto:IBM-MAIN@LISTSERV.UA.EDU] On > Behalf Of David Crayford > Sent: Sunday, July 21, 2013 8:31 PM > To: IBM-MAIN@LISTSERV.UA.EDU > Subject: Re: Looking for help with an obscure C integer problem > > I'm struggling to see what is wrong with testWord = valueToTest >> 32. > There are no side effects and the sequence point is at the end of the full > expression. Can anybody enlighten me? > Charles, is the code snippet you supplied the exact test cast that is > resulting in undefined behaviour? I cannot recreate the problem and I've > tried it on five different C++ compilers, including z/OS v1.13. > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
