Re: Re: MLton codegen combines divison on arm

On Sat, Nov 13, 2010 at 1:27 PM, Adam Goode <[email protected]> wrote:
> On 11/11/2010 10:49 AM, Wesley W. Terpstra wrote:
>> On Thu, Nov 11, 2010 at 3:15 PM, Matthew Fluet <[email protected]> wrote:
>>> Were you able to declare success with the ARM floating-point rounding?
>> What needs to be done IMO is to turn on the rounding mode support in
>> libgcc. It's absurd that something as simple as wiring it to a public
>> symbol is considered a roadblock to fixing this problem. I don't have
>> the time or energy needed to try and push a change like this through
>> the sorts of people who gather around libc development.
>>
>
> It is not this simple.
> If you are using software floating point, then, at a start, you need to hack these files:

I did say there is some assembler code that doesn't support rounding
modes which is used in some configurations. However, there is also a
nice C library in libgcc which DOES support rounding modes. Where that
is enabled, it IS as simple as exporting a symbol that can control the
rounding mode.

I suppose there are people who prefer performance over correctness,
and these people may prefer the assembler emulation to the C
emulation. Since both are broken at the moment, I guess there is no
downside to the assembler variant. If the C variant were fixed, in my
opinion correctness should trump speed with default compile options.