unw_get_fpreg -- get contents of floating-point register

       David Mosberger-Tang
       Email: dmosberger@gmail.com
       WWW: http://www.nongnu.org/libunwind/.

Programming Library                              16 August 2007                                 UNW_GET_FPREG(3)

       The  unw_get_fpreg() routine reads the value of floating-point register reg in the stack frame identified
       by cursor cp and stores the value in the variable pointed to by valp.

       The  register  numbering  is  target-dependent  and   described   in   separate   manual   pages   (e.g.,
       libunwind-ia64(3)  for  the IA-64 target).  Furthermore, the exact set of accessible registers may depend
       on the type of frame that cp is referring to. For ordinary stack  frames,  it  is  normally  possible  to
       access  only  the  preserved  (``callee-saved'')  registers  and  frame-related  registers  (such  as the
       stack-pointer). However, for signal frames (see unw_is_signal_frame(3)), it is usually possible to access
       all registers.

       Note that unw_get_fpreg() can only read the contents of floating-point  registers.  See  unw_get_fpreg(3)
       for a way to read registers which fit in a single word.

       UNW_EUNSPEC
               An unspecified error occurred.

       UNW_EBADREG
               An attempt was made to read a register that is either invalid or not accessible  in  the  current
              frame.

       In  addition,  unw_get_fpreg()  may  return  any  error  returned  by the access_mem(), access_reg(), and
       access_fpreg() call-backs (see unw_create_addr_space(3)).

       unw_get_fpreg -- get contents of floating-point register

       On  successful  completion,  unw_get_fpreg()  returns  0.   Otherwise  the  negative  value of one of the
       error-codes below is returned.

libunwind(3),     libunwind-ia64(3),     unw_get_reg(3),     unw_is_fpreg(3),     unw_is_signal_frame(3),
       unw_set_fpreg(3)

       #include <libunwind.h>

       int unw_get_fpreg(unw_cursor_t *cp, unw_regnum_t reg, unw_fpreg_t *valp);

       unw_get_fpreg() is thread-safe as well as safe to use from a signal handler.