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Release 7.1.1 new features

New user context structure and floating point context flag

A new extended user context structure in /usr/include/sys/ucontext.h has been added for extended floating point instruction support:

   typedef struct uxcontext uxcontext_t;

The extended user context structure is identical to the existing user context structure (see ucontext(5)) except that it has an element for a 512-byte extended floating point save area appended to the end:

   __fpxregset_t __fpxregset;

A new floating point context flag in /usr/include/sys/ucontext.h has also been added:

   #define UC_FPX 020

The uc_flags element of the user context structure is used to determine if a user context is extended.

If UC_FPX is cleared in the uc_flags element of a user context structure, then the user context is assumed to be of type ucontext_t.

If UC_FPX is set and UC_FP is cleared in the uc_flags element of a user context structure, then the user context is assumed to be of type uxcontext_t with the extended floating point state saved in the __fpxregset element.

Normally, applications should not set both UC_FPX and UC_FP in the uc_flags element of a user context structure. If both UC_FPX and UC_FP are set in the uc_flags element, then the user context is assumed to have been pushed on the user stack during signal handling. This is treated as a special case by the setcontext(2) system call. See the notes on signal handling below for more details.


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UnixWare 7 Release 7.1.4 - 22 April 2004