It's wasteful to compute everything with long double precision when we
don't need it, so this change will be required down the road when we get
to make erf precise and fast. For the time being, this is more a
cosmetic change to align this implementation with others.
This is required to obtain results for large values of `x`. The Gamma
function can produce extremely large values, causing `gamma(x)` to
return `inf` even when `lgamma(x)` can still return a finite result.
We know that x != 0 and extractor.exponent == 0 at the bottom
of the function, meaning mantissa must be != 0.
And the `extractor.exponent = exponent + 1;` store overwrites
the store on the line above. (Presumably, the line above meant
to shift `mantissa` instead.)
No behavior change.
The motivation is to allow functions that use FloatExtractor to be
constexpr. Type punning through a union will never work in constexpr.
In practice, bit_cast<>()ing bit fields also does not yet work in clang,
but that's just a bug and it will work eventually (and it does already
work in gcc): https://github.com/llvm/llvm-project/issues/54018
No behavior change.
Contrary to IEEE formats, x86's 80-bit extended floats need the topmost
mantissa bit to be 1 or else a special kind of NaN is produced. We fix
this by reinserting the special bit if necessary.
Whenever the floating-point values are in integer range, we can use the
various FCVT functions with static rounding mode to perform fast
rounding. I took this opportunity to clean up the architecture
differentiation for these functions, which allows us to use the software
rounding implementation for all extreme and unimplemented cases,
including AArch64.
Also adds more round & trunc tests.
These instances were detected by searching for files that include
stdlib.h, but don't match the regex:
\\b(_abort|abort|abs|aligned_alloc|arc4random|arc4random_buf|arc4random_
uniform|atexit|atof|atoi|atol|atoll|bsearch|calloc|clearenv|div|div_t|ex
it|_Exit|EXIT_FAILURE|EXIT_SUCCESS|free|getenv|getprogname|grantpt|labs|
ldiv|ldiv_t|llabs|lldiv|lldiv_t|malloc|malloc_good_size|malloc_size|mble
n|mbstowcs|mbtowc|mkdtemp|mkstemp|mkstemps|mktemp|posix_memalign|posix_o
penpt|ptsname|ptsname_r|putenv|qsort|qsort_r|rand|RAND_MAX|random|reallo
c|realpath|secure_getenv|serenity_dump_malloc_stats|serenity_setenv|sete
nv|setprogname|srand|srandom|strtod|strtof|strtol|strtold|strtoll|strtou
l|strtoull|system|unlockpt|unsetenv|wcstombs|wctomb)\\b
(Without the linebreaks.)
This regex is pessimistic, so there might be more files that don't
actually use anything from the stdlib.
In theory, one might use LibCPP to detect things like this
automatically, but let's do this one step after another.
Even though this almost certainly wouldn't run properly even if we had
a working kernel for AARCH64 this at least lets us build all the
userland binaries.
Doesn't use them in libc headers so that those don't have to pull in
AK/Platform.h.
AK_COMPILER_GCC is set _only_ for gcc, not for clang too. (__GNUC__ is
defined in clang builds as well.) Using AK_COMPILER_GCC simplifies
things some.
AK_COMPILER_CLANG isn't as much of a win, other than that it's
consistent with AK_COMPILER_GCC.
Lucas Chollet