Re: Problem using Ada.Text_IO.Modular_IO

[anon@anon.org (anon)]

In GNAT the types and functions define by packages "Standard.ads" and 
some others like "Interfaces.ads" are treated as special. 

Note: In GNAT you will not see a package called "Standard" it 
is built-into the compiler.  To check this package you can use 
"-gnatS" (version GNAT 2005-8) in a command line. Such as:

  gnat1 <any ada source file>adb -gnatS  >standard.ads

As for the "Interfaces" package the compiler uses if possible a machine 
instruction to preform the function. So, when the compile encounters a 
call to the function "Rotate_Left" for example on a Intel cpu the 
compiler will use the Intel processor instruction "rol".

To see an example. Create a test program and compile it using either 
the following commands. Two files are create (*.s, and *.ali).

   gnat compile <test file name>.adb  -S  <other options if needed>

or

   gnat1 <test file name>.adb  <other options if needed>

Note: the output of "GNAT1" when excuted by a command line/batch file 
is normally a assembly source file for the target cpu with its assoc *.ali 
file.

Then just check the file: <test file name>.s 

Note: the "*.s" can be compiled and then you can use gnatbind/gnatlink 
to continue to build the program.




In <93bcf03d-dd09-4cdd-b4a7-98bf56284ee3@k37g2000hsf.googlegroups.com>, micronian2@gmail.com writes:
>On Jul 14, 6:12=A0am, Georg Bauhaus <rm.dash-bauh...@futureapps.de>
>wrote:
>> anon schrieb:
>[snip]
>> Q: What routines does the compiler generate for Unsigned_64
>> =A0 =A0 but not for "mod 2**64" and vice versa?
>> A: None.
>>
>
>Your "mod 2**64" won't get Shift_Arithmetic_Right, Rotate_Left, and
>Rotate_Right. After some thought, I realized that you can simulate
>Rotate_Left/Right with shift operations. For example,
>Rotate_Left(Value, 3) can be performed by doing:
>
> Value :=3D (Value * 2**3) or (Value / 2**29) (note: assuming value is
>32-bits)
>
>For constant values, the compiled output has a good chance of being
>the same for either "mod 2**64" and Unsigned_64. But what about cases
>where the shift offsets are not known at compile time?  I wrote two
>little test programs to see how user defined shift and rotate
>operations for "mod**64" compared to those that were predefined for
>Interfaces.Unsigned_64 using GNAT GPL2008. For the shift left/right
>operations, the output was the pretty much the same. For the rotate
>left/right, the ones for Unsigned_64 generated less code and did not
>need as many calls to the run-time system. Of course, this is all just
>based on one compiler. I don't know what other compilers do. Actually
>I do recall the old GreenHills AdaMULTI 3.0 compiler implemented the
>operations as calls to C functions.
>
>Anyhow, I think I said enough on this.
>