We assume we are compiled on a base-2 radix floating point system. This
is a reasonable assumption. musl libc as an example also assumes this.
We implement scalbn as an alias for ldexp, since ldexp is defined as 2
regardless of the float radix. This is opposite to musl which defines
scalbn in terms of ldexp.
Closes#9799.
These changes have been made to resolve issue #10037. The `Random`
interface was implemented in such a way that causes significant slowdown
when calling the `fill` function of the rng used.
The `Random` interface is no longer stored in a field of the rng, and is
instead returned by the child function `random()` of the rng. This
avoids the performance issues caused by the interface.
* Fix bug in exp2_64 to handle negative values (bad translation from C)
* Apply fix to exp2_32() as well, and modify comment on musl behaviour
* Use +%= instead of @addWithOverflow()
AIR:
* div is renamed to div_trunc.
* Add div_float, div_floor, div_exact.
- Implemented in Sema and LLVM codegen. C backend has a stub.
Improvements to std.math.big.Int:
* Add `eqZero` function to `Mutable`.
* Fix incorrect results for `divFloor`.
Compiler-rt:
* Add muloti4 to the stage2 section.
libc requires this to use `long double` which is sometimes the same as
f128, sometimes not.
Also for an unknown reason, aarch64 is getting an invalid result for the
`@mulAdd` behavior test for f128. See #9900.
std: add f128 implementations of fma, frexp, and ilogb. Expose `fmal` in
zig's freestanding libc. This makes `@mulAdd` work correctly for f128.
Fixes a CI regression from yesterday, where I added a usage of f128
`@mulAdd` into the self-hosted compiler.
Before, Sema for comptime `@bitCast` would return the same Value but
change the Type. This gave invalid results because, for example, an
integer Value when the Type is a float would be interpreted numerically,
but `@bitCast` needs it to reinterpret how they would be stored in
memory.
This requires a mechanism to serialize a Value to a byte buffer and
deserialize a Value from a byte buffer.
Not done yet, but needs to happen: comptime dereferencing a pointer
to a Decl needs to perform a comptime bitcast on the loaded value.
Currently the value is silently wrong in the same way that `@bitCast`
was silently wrong before this commit.
The logic in Value for handling readFromMemory for large integers is
only correct for small integers. It needs to be fleshed out for proper
big integers.
As part of this change:
* std.math.big.Int: initial implementations of readTwosComplement and
writeTwosComplement. They only support bit_count <= 128 so far and
panic otherwise.
* compiler-rt: move the compareXf2 exports over to the stage2 section.
Even with the improvements in this commit, I'm still seeing test
failures in the widening behavior tests; more investigation is
needed.
This function can be used to initialize a big integer to either the upper
or lower limit of a 2s-complement integer. Note that the result is still
in sign-magnitude representation, though in order to convert it into twos
complement all one has to do is take the absolute value.
lladd is now implemented in terms of lladdcarry, which returns the carry limb.
Similarly, llsub is implemented using llsubcarry, which returns the borrow limb.
