[fpc-pascal] 32 to 64 bits

[JoshyFun]

Hello Marco,

Saturday, January 10, 2009, 12:36:37 AM, you wrote:

MvdV> Afaik most is in the docs, but some short pointers:

Sure :) but as I said not found :( and the information I had found
does not describe the 32/64 bits differences.

MvdV>                              32           64
MvdV>    unsigned 16 bits          WORD?        WORD?
MvdV>    signed 16 bits            see table docs (smallint/shortint)
MvdV>    unsigned 32 bits          DWORD?       DWORD?
MvdV>    signed 32 bits            compiler mode dependant 16/32

Hmmm... I was asking only for 32/64 differences (my targetted systems)
but 16 bits is interesting also. For 32/64 this should be the LongInt
do not ?

MvdV>    unsigned 64 bits          QWORD?       QWORD?
MvdV>    signed 64 bits            Int64?       Int64?
MvdV>    Native "integer"          "native" is ambiguous.
MvdV>    Signed integer as big
MvdV>      as pointer              PtrInt       Ptrint

PtrInt does not have too much sense :-? There are not negative memory
addresses.

MvdV>    Unsigned integer as big
MvdV>      as pointer              PtruInt      Ptruint
   
MvdV> "native" is confusing since it can taken in many ways. Native as in most
MvdV> performance? Register size? Addressing size? Addressing size + segment ?
MvdV> (size_t, ssize_t).

Well, I understand "native" as the less efforce variable to be
loaded/written to memory, in 32/64 bits usually it is the register
size.

>> Where LongInt fits ? Bits dependent or not ?
MvdV> always 32-bit signed.

And "integer" ? Is it always 32 bits ? Oh! I found the table in the
documentation finally :) Integer is 16/32/64 bits (the thing I call it
"native").

But there is something that I do not understand in this table. The doc
says:

"The cardinal type is currently always mapped to the longword type.
The definition of the cardinal and integer types may change from one
architecture to another and from one compiler mode to another."

"Always" or "may change" ? :-?
 
MvdV> The docs are the primary source, the language ref should have a table
MvdV> somewhere near the start. I sometimes use it, because I always forget which
MvdV> is 8-bit signed and which is 16-bit signed. (which is why I never use them
MvdV> and always use ctypes)

Yes, ctypes could be my solution too. Thank you for your help.

-- 
Best regards,
 JoshyFun