Hello,

I'm dealing with the following code (from ZenGL library), targeting OSX ---------------
{$mode delphi}

procedure m_SinCos( Angle : Single; out s, c : Single ); assembler; asm
FLD Angle
FSINCOS
FSTP [EDX]
FSTP [EAX]
end;

var
  s,c: single;
begin
  m_SinCos(0,s,c);
end.
---------------

The latest Xcode 7.0 tools does recognize the generated assembler (fpc trunk):
---------
# [5] FLD Angle
flds 8(%ebp)
# [6] FSINCOS
fsincos
# [7] FSTP [EDX]
fstp (%edx)
# [8] FSTP [EAX]
fstp (%eax)
---------

as a problem:

Assembling program
test.s:21:2: error: ambiguous instructions require an explicit suffix (could be 'fstps', 'fstpl', or 'fstpt')
fstp (%edx)
^
test.s:23:2: error: ambiguous instructions require an explicit suffix (could be 'fstps', 'fstpl', or 'fstpt')
fstp (%eax)

One interested could search the internet for the problem encountered with other platforms, and find out that the newer clang is somewhat backward incompatible.

My first attempt was to replace to put the suggested FSTPS instruction in place:
FSTPS [EDX]
However, the compiler stopped me, complaining about "FSTPS" is not a recognized instruction.

The next approach was to rewrite the function into at&t syntax. (The actual implementation could be found at sincos() of RTL math unit).

Is it a yet to be developed feature for FPC to satisfy demands of external tools relies on?

I presume since the compiler parses intel asm and translates it into at&t asm, it should take into consideration requirements of the latest osx building tools.
Or is it already supported and I'm just missing a compiler switch?

thanks,
Dmitry

I think the correct solution for you is to use explicit size information:

FSTP SINGLE PTR [EDX]

FSTP SINGLE PTR [EAX]

but

FSTP [s]

and

FSTP [c]

would be even better, I don’t know if this syntax is Delphi compatible or not.

It seems that indeed Free Pascal does not set the size of those instruction,

but seems to use single as default size for internal code generation…

When generating assembler file for GNU assembler or NASM,

it does not seem to print out this “assumed” size, which indeed

leads to a failure using –Anasm option on trunk compiler with i386-win32 target.

My GNU as version 2.26 does not seem to need an explicit size,

but I don’t know what Xcode uses, isn’t it also a GNU assembler?

Could you tell us which assembler is used?

Pierre

De : De la part de Dmitry Boyarintsev
Envoyé : mercredi 4 mai 2016 02:28
À : FPC-Pascal users discussions
Objet : [fpc-pascal] intel vs att asm (fstp instruction) (osx/clang features)

Hello,

I'm dealing with the following code (from ZenGL library), targeting OSX

---------------

{$mode delphi}
procedure m_SinCos( Angle : Single; out s, c : Single ); assembler;

asm

FLD Angle

FSINCOS

FSTP [EDX]

FSTP [EAX]

end;
var
  s,c: single;
begin
  m_SinCos(0,s,c);
end.

---------------

The latest Xcode 7.0 tools does recognize the generated assembler (fpc trunk):

---------

# [5] FLD Angle

flds 8(%ebp)

# [6] FSINCOS

fsincos

# [7] FSTP [EDX]

fstp (%edx)

# [8] FSTP [EAX]

fstp (%eax)

---------

as a problem:

Assembling program

test.s:21:2: error: ambiguous instructions require an explicit suffix (could be 'fstps', 'fstpl', or 'fstpt')

fstp (%edx)

^

test.s:23:2: error: ambiguous instructions require an explicit suffix (could be 'fstps', 'fstpl', or 'fstpt')

fstp (%eax)

One interested could search the internet for the problem encountered with other platforms, and find out that the newer clang is somewhat backward incompatible.

My first attempt was to replace to put the suggested FSTPS instruction in place:

FSTPS [EDX]

However, the compiler stopped me, complaining about "FSTPS" is not a recognized instruction.

The next approach was to rewrite the function into at&t syntax. (The actual implementation could be found at sincos() of RTL math unit).

Is it a yet to be developed feature for FPC to satisfy demands of external tools relies on?

I presume since the compiler parses intel asm and translates it into at&t asm, it should take into consideration requirements of the latest osx building tools.

Or is it already supported and I'm just missing a compiler switch?

thanks,

Dmitry

Hello,

I have something like this which seems to work very nicely

Cheers, Ched'

PROCEDURE SINCOS(CONST X: DOUBLE; VAR S, C: DOUBLE);
BEGIN
    {$IFDEF NOASM}
       S:=SIN(X);
       C:=COS(X);
    {$ELSE}
       {$IFDEF VER70}
          IF TEST8087=3 THEN
             ASM
                FLD   X
                DB    $D9,$FB
                LES   DI,C
                FSTP  DOUBLE(ES:[DI])
                LES   DI,S
                FSTP  DOUBLE(ES:[DI])
             END
          ELSE
             BEGIN
                S:=SYSTEM.SIN(X);
                C:=SYSTEM.COS(X);
             END;
       {$ELSE}
           ASM
              FLD X
              FSINCOS
              MOV  ECX,C
              FSTP DOUBLE([ECX])
              MOV  ECX,S
              FSTP DOUBLE([ECX])
           END
       {$ENDIF}
    {$ENDIF}
END;

Indeed that worked as expected. Thank you.

It still requires explicit size information, like
FSTP SINGLE [s]

It's Apple's clang IIRC Apple stopped using gnu-tools since Xcode 3.2 or something like that.
Here are more exact details:

$ as -v
Apple LLVM version 7.3.0 (clang-703.0.29)
Target: x86_64-apple-darwin15.3.0
Thread model: posix
InstalledDir:
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin "/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang" -cc1as -triple x86_64-apple-macosx10.11.0 -filetype obj -main-file-name - -target-cpu core2 -dwarf-version=2 -fdebug-compilation-dir /Users/dmitry/FPC_Laz -dwarf-debug-producer Apple LLVM version 7.3.0 (clang-703.0.29) -mrelocation-model pic -o a.out -

thanks,
Dmitry