o Make sure the arguments to ctx_wrapper() are loaded from the
backing store by forcing an underflow. Do this by making all
registers in the register frame local.
o Up to 8 arguments are allowed. This is the number of arguments
passed in registers. Subsequent registers are passed on the stack.
Trying to deal with this is not easy in C and likely forces us to
use assembly code. Let's avoid that for now. There's no indication
that more than 8 arguments is a strong requirement (Linux also has
an 8 argument limit).
o We expect that the stack base is 16-byte aligned and the stack
size is a multiple of 16-byte. We bomb out if this is not the case.
We probably want to be less strict by enforcing it ourselves. For
now it's better to not hide gross alignment bogons by silently
correcting it.
not save (restore) the global pointer (GP) in the jmpbuf in setjmp
(longjmp) because it's not needed in general. GP is considered a
scratch register at callsites and hence is always restored after a
call (when it's possible that the call resolves to a symbol in a
different loadmodule; otherwise GP does not have to be saved and
restored at all), including calls to setjmp/longjmp. There's just
one problem with this now that we use setjmp/longjmp for context
switching: A new context must have GP defined properly for the
thread's entry point. This means that we need to put GP in the
jmpbuf and consequently that we have to restore is in longjmp.
This automaticly requires us to save it as well.
When setjmp/longjmp isn't used for context switching, this can be
reverted again.
the J_SIG0 field. While here, rename J_SIG0 to J_SIGSET and
remove J_SIG1. The main reason for this change is that the
128-bit sigset_t is now aligned on a 16-byte boundary, which
allows us to use 16-byte atomic loads and stores on CPUs that
support it. The removal of J_SIG1 is done to avoid confusion:
it is never accessed and should not be. Renaming J_SIG0 to
J_SIGSET is the icing on the cake that's better done now than
later.
isnormal(). The current isinf() and isnan() are perserved for
binary compatibility with 5.0, but new programs will use the macros.
o Implement C99 comparison macros isgreater(), isgreaterequal(),
isless(), islessequal(), islessgreater(), isunordered().
Submitted by: David Schultz <dschultz@uclink.Berkeley.EDU>
o Add a MD header private to libc called _fpmath.h; this header
contains bitfield layouts of MD floating-point types.
o Add a MI header private to libc called fpmath.h; this header
contains bitfield layouts of MI floating-point types.
o Add private libc variables to lib/libc/$arch/gen/infinity.c for
storing NaN values.
o Add __double_t and __float_t to <machine/_types.h>, and provide
double_t and float_t typedefs in <math.h>.
o Add some C99 manifest constants (FP_ILOGB0, FP_ILOGBNAN, HUGE_VALF,
HUGE_VALL, INFINITY, NAN, and return values for fpclassify()) to
<math.h> and others (FLT_EVAL_METHOD, DECIMAL_DIG) to <float.h> via
<machine/float.h>.
o Add C99 macro fpclassify() which calls __fpclassify{d,f,l}() based
on the size of its argument. __fpclassifyl() is never called on
alpha because (sizeof(long double) == sizeof(double)), which is good
since __fpclassifyl() can't deal with such a small `long double'.
This was developed by David Schultz and myself with input from bde and
fenner.
PR: 23103
Submitted by: David Schultz <dschultz@uclink.Berkeley.EDU>
(significant portions)
Reviewed by: bde, fenner (earlier versions)
o Remove the unwanted smartness in _longjmp() where it compares
the current ar.bspstore with the saved ar.bspstore and restores
ar.rnat based on it. This either avoids saving ar.rnat in the
jmp_buf or is the consequence of not saving ar.rnat. All this
complexity breaks libc_r where we use longjmp() to switch to
different threads and the current ar.bspstore has no relation
to the saved ar.bspstore. Thus: we save ar.rnat in setjmp()
and simply restore ar.bspstore and ar.rnat in longjmp().
This code needs a cleanup.
Don't force 16-byte alignment at run-time. Do it at compile-time.
This saves us the pointer fiddling by the setjmp functions and
reduces complexity. While here, increase the jmp_buf by 16 bytes
to an even 512 bytes. Coincidentally, due to the way alignment
was handled prior to this change, the jmp_buf has not changed in
size, but only in how the space is used. Prior to this change
the 16 bytes were reserved for enforcing alignment; now they are
reserved by us for future extensions.
Therefore, this ABI breaker is relatively save: the failure is
always an alignment trap.
HUGE_VAL is not properly aligned on some architectures. The previous
fix now works because the two versions of 'math.h' (include/math.h
and lib/msun/src/math.h) have since been merged into one.
PR: bin/43544
adding (weak definitions to) stubs for some of the pthread
functions. If the threads library is linked in, the real
pthread functions will pulled in.
Use the following convention for system calls wrapped by the
threads library:
__sys_foo - actual system call
_foo - weak definition to __sys_foo
foo - weak definition to __sys_foo
Change all libc uses of system calls wrapped by the threads
library from foo to _foo. In order to define the prototypes
for _foo(), we introduce namespace.h and un-namespace.h
(suggested by bde). All files that need to reference these
system calls, should include namespace.h before any standard
includes, then include un-namespace.h after the standard
includes and before any local includes. <db.h> is an exception
and shouldn't be included in between namespace.h and
un-namespace.h namespace.h will define foo to _foo, and
un-namespace.h will undefine foo.
Try to eliminate some of the recursive calls to MT-safe
functions in libc/stdio in preparation for adding a mutex
to FILE. We have recursive mutexes, but would like to avoid
using them if possible.
Remove uneeded includes of <errno.h> from a few files.
Add $FreeBSD$ to a few files in order to pass commitprep.
Approved by: -arch
