[Vm-dev] SqueakFFI 32-bit (win) | int64_t not working for negative integers

Marcel Taeumel marcel.taeumel at hpi.de
Tue Apr 12 08:55:33 UTC 2022


Hi Nicolas --

Thanks for the tip. I will have a look.

Do you know whether Squeak FFI 32-bit does (or should) support "long long" (or "int64_t") for Large(Positive|Negative)Integer outside the range of int32_t?

On 32-bit Squeak, we need both SmallInteger and Large(Positive|Negative)Integer to cover int32_t. Not so on 64-bit Squeak. So, I am not sure whether there is actually support for int64_t on 32-bit Squeak in this regard...

So, am I looking for a bug or would this rather be a new feature? :-)

Best,
Marcel
Am 11.04.2022 21:31:58 schrieb Nicolas Cellier <nicolas.cellier.aka.nice at gmail.com>:
Hi Marcel,
Sounds like 32bits -1 missing a sign extension when converted to 64bits...
At least, the result is correctly 64bits for sure.

Le lun. 11 avr. 2022 à 18:42, Marcel Taeumel a
écrit :

>
> Hi all --
>
> This is not working in 32-bit on Windows:
>
> FFITestLibrary ffiTest8LongLongSum: -1 with: -1 with: -1 with: -1 with: -1
> with: -1 with: -1 with: -1.
>
> It answers " 34359738360 " instead of " - 8 ". It's working fine in a
> 64-bit build. The debugging output in this test functions says:
>
> 8 long longs came in as
> i1 = 4294967295 (ffffffff)
> i2 = 4294967295 (ffffffff)
> i3 = 4294967295 (ffffffff)
> i4 = 4294967295 (ffffffff)
> i5 = 4294967295 (ffffffff)
> i6 = 4294967295 (ffffffff)
> i7 = 4294967295 (ffffffff)
> i8 = 4294967295 (ffffffff)
>
> ... this is clearly wrong. Or is it? On 64-bit, the same function says:
>
> 8 long longs came in as
> i1 = -1 (ffffffffffffffff)
> i2 = -1 (ffffffffffffffff)
> i3 = -1 (ffffffffffffffff)
> i4 = -1 (ffffffffffffffff)
> i5 = -1 (ffffffffffffffff)
> i6 = -1 (ffffffffffffffff)
> i7 = -1 (ffffffffffffffff)
> i8 = -1 (ffffffffffffffff)
>
> Both are formatted via " %lld (%llx) " I am missing something here... did
> we change the representation of negative integers in Squeak and forgot to
> update something along ThreadedFFIPlugin >> #ffiIntegerValueOf:? :-/
>
> Best,
> Marcel
>
> ***
>
> EXPORT(long long) ffiTest8LongLongSum(long long c1, long long c2, long
> long c3, long long c4, long long c5, long long c6, long long c7, long long
> c8)
> {
> printf("8 long longs came in as\ni1 = %lld (%llx)\ni2 = %lld (%llx)\ni3 =
> %lld (%llx)\ni4 = %lld (%llx)\ni5 = %lld (%llx)\ni6 = %lld (%llx)\ni7 =
> %lld (%llx)\ni8 = %lld (%llx)\n", c1, c1, c2, c2, c3, c3, c4, c4, c5, c5,
> c6, c6, c7, c7, c8, c8);
> return c1 + c2 + c3 + c4 + c5 + c6 + c7 + c8;
> }
>

Hi Marcel,
Sounds like 32bits -1 missing a sign extension when converted to 64bits...
At least, the result is correctly 64bits for sure.

Le lun. 11 avr. 2022 à 18:42, Marcel Taeumel <marcel.taeumel at hpi.de [mailto:marcel.taeumel at hpi.de]> a écrit :

 
Hi all --

This is not working in 32-bit on Windows:

FFITestLibrary ffiTest8LongLongSum: -1 with: -1 with: -1 with: -1 with: -1 with: -1 with: -1 with: -1.


It answers " 34359738360 " instead of " - 8 ". It's working fine in a 64-bit build. The debugging output in this test functions says:

8 long longs came in as
i1 = 4294967295 (ffffffff)
i2 = 4294967295 (ffffffff)
i3 = 4294967295 (ffffffff)
i4 = 4294967295 (ffffffff)
i5 = 4294967295 (ffffffff)
i6 = 4294967295 (ffffffff)
i7 = 4294967295 (ffffffff)
i8 = 4294967295 (ffffffff)

... this is clearly wrong. Or is it? On 64-bit, the same function says:

8 long longs came in as
i1 = -1 (ffffffffffffffff)
i2 = -1 (ffffffffffffffff)
i3 = -1 (ffffffffffffffff)
i4 = -1 (ffffffffffffffff)
i5 = -1 (ffffffffffffffff)
i6 = -1 (ffffffffffffffff)
i7 = -1 (ffffffffffffffff)
i8 = -1 (ffffffffffffffff)

Both are formatted via " %lld (%llx) " I am missing something here... did we change the representation of negative integers in Squeak and forgot to update something along ThreadedFFIPlugin >> #ffiIntegerValueOf:? :-/

Best,
Marcel

***

EXPORT(long long) ffiTest8LongLongSum(long long c1, long long c2, long long c3, long long c4, long long c5, long long c6, long long c7, long long c8)
{
printf("8 long longs came in as\ni1 = %lld (%llx)\ni2 = %lld (%llx)\ni3 = %lld (%llx)\ni4 = %lld (%llx)\ni5 = %lld (%llx)\ni6 = %lld (%llx)\ni7 = %lld (%llx)\ni8 = %lld (%llx)\n", c1, c1, c2, c2, c3, c3, c4, c4, c5, c5, c6, c6, c7, c7, c8, c8);
return c1 + c2 + c3 + c4 + c5 + c6 + c7 + c8;
}
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