We compute atan2f(y, x) in 2 stages:
- Fast step: perform computations in double precision , with relative
errors < 2^-50
- Accurate step: if the result from the Fast step fails Ziv's rounding
test, then we perform computations in double-double precision, with
relative errors < 2^-100.
On Ryzen 5900X, worst-case latency is ~ 200 clocks, compared to average
latency ~ 60 clocks, and average reciprocal throughput ~ 20 clocks.
Continuing #84689, this one required more changes than the others, so I
am making it a separate PR.
Extends some stuff in `str_to_float.h`, `str_to_integer.h` to work on
types wider than `unsigned long long` and `uint64_t`.
cc @lntue for review.
- Allow `FMod` template to have different computational types and make
it work for 80-bit long double.
- Switch to use `uint64_t` as the intermediate computational types for
`float`, significantly reduce the latency of `fmodf` when the exponent
difference is large.
Summary:
I've noticed one problem is that the user includes `stdint.h` the
compiler will do `#include_next <stdint.h>` potentially into a
conflicting implementation on systems with multiple headers installed.
The `clang` header is standards compliant and works with `clang` and
`gcc` which are both of our targets, so I simply copied it here. This
has the effect of including `stdint.h` on clang / LLVM libc behaving the
same as `-ffreestanding`.
The epoll_wait functions are syscall wrappers that were requested by
upstream users. This patch adds them, as well as their header and types.
The tests are currently incomplete since they require epoll_create to
properly test epoll_wait. That will be added in a followup patch since
this one is already very large.
The epoll_wait functions are syscall wrappers that were requested by
upstream users. This patch adds them, as well as their header and types.
The tests are currently incomplete since they require epoll_create to
properly test epoll_wait. That will be added in a followup patch since
this one is already very large.
__stack_chk_fail should be provided by libc.a, not startup files.
Add __stack_chk_fail to existing linux and arm entrypoints. On Windows
(when
not targeting MinGW), it seems that the corresponding function
identifier is
__security_check_cookie, so no entrypoint is added for Windows.
Baremetal
targets also ought to be compileable with `-fstack-protector*`
There is no common header for this prototype, since calls to
__stack_chk_fail
are meant to be inserted by the compiler upon function return when
compiled
`-fstack-protector*`.
Implement `prctl` as specified in
https://man7.org/linux/man-pages/man2/prctl.2.html.
This patch also includes test cases covering two simple use cases:
1. `PR_GET_NAME/PR_SET_NAME`: where userspace data is passed via arg2.
2. `PR_GET_THP_DISABLE`: where return value is passed via syscal retval.
The test cases of mincore require getting correct page size from OS. As
`sysconf` is not functioning correctly, these patches are implemented in
a somewhat confusing way. We revert such patches and will reintroduce
mincore after we correct sysconf.
This reverts 54878b8, 985c0d1 and 418a3a4.
