All of these operations were only testing positive integers which is why
they didn't show 16-bit failures.
Adds a bunch of negative tests to each ones now that #2314 is merged,
which would have caught them.
unit tests that show the difference of output between FPREM and FPREM1.
Setup as known failures on everything except for host since we don't
implement fprem correctly.
An incorrect fix to FPREM is as follows:
```diff
--- a/External/FEXCore/Source/Common/SoftFloat.h
+++ b/External/FEXCore/Source/Common/SoftFloat.h
@@ -158,6 +158,10 @@ struct X80SoftFloat {
return Result;
#else
+ BIGFLOAT lhs_ = lhs;
+ BIGFLOAT rhs_ = rhs;
+ BIGFLOAT Result = fmodl(lhs_, rhs_);
+ return Result;
return extF80_rem(lhs, rhs);
#endif
}
```
But we shouldn't implement this fix. We should instead implement a new `extF80_mod`
function that handles the rounding differences between FPREM and FPREM1.
Fixes#2097.
Doesn't attempt to resolve#1538
I misread the implementation details of this instruction when
implementing.
The pseudocode says `ST(0) = ST(0) ∗ 2^rndint(ST(1))` so I understood
the instruction to use the current rounding mode of the host to extract
the integer portion of `ST(1)`.
The actual implementation is in the details of the statement `the
integer portion of the floating- point value in ST(1).`
This behaves like round towards zero/truncate, additional hardware
testing and documentation reading confirms this.
Fixes#1584
Wine was doing a fun x87 stack clean by checking tag bits for empty.
We hadn't previously supported anything but valid. Which cause wine to overflow the stack
trying to save all of the x87 values.
We now support valid and empty well enough that this doesn't break and we can unit test it
If the input range is outside of -1.0 to +1.0 then the result is
undefined.
To avoid precision problems just check for zero, aka 2^0-1 which also
returns zero
Most of these were relying on the upper 16bits of the 80bit MM registers
to be zero.
This isn't necessarily true as one will find out when running this under
the host runner.
