Tim,
ARM was a different case. Andrew Fish can provide many of the details. Basic
issue was that even 32-bit math ops were generating intrinsic calls and to
apply same technique we have use for 64-bit math ops would have required
conversion of most =-*/% operations on UINT32 or UINTN values to be converted
to function calls in all modules. I believe Andrew also provided background
that the intrinsic calls to support 32-bit math ops were fully documented and
supported by all ARM compilers.
I get the impression that the real issue here are the obscure linker error
messages and the extra steps/time required to identify he C source line that is
introducing the use of the intrinsic call. Another option to consider is to
improve the tools to help identify the C source line that is generating the
intrinsic along with a recommended C source change to resolve the issue.
As Daryl said, if there is strong interest in making the intrinsic functions in
the AppPkg their own lib, he would consider that change. I think that would
provide a partial solution.
Best regards,
Mike
From: Tim Lewis [mailto:tim.le...@insyde.com]
Sent: Wednesday, August 20, 2014 3:39 PM
To: edk2-devel@lists.sourceforge.net
Subject: Re: [edk2] [StdLib] Patch for review: Add VC++ helper function for
64-bit right shift
Mike –
However, as compilers do require intrinsic functions in order to support basic
C/C++ operators, and as the ArmPkg has already implemented this sort of
function for support of ARM tool chains, and as it regularly causes compile
failures for reasons obscure even to engineers well versed in the art, I think
it is time to revisit that decision. Raise your hand if you have done a search
on u
Even a partial solution will be better than no solutions because the net result
is fewer hard-to-understand linker errors than before. If you miss one
function, the net result is no worse than today.
Tim
From: Kinney, Michael D [mailto:michael.d.kin...@intel.com]
Sent: Wednesday, August 20, 2014 12:30 PM
To: edk2-devel@lists.sourceforge.net<mailto:edk2-devel@lists.sourceforge.net>
Subject: Re: [edk2] [StdLib] Patch for review: Add VC++ helper function for
64-bit right shift
Thomas,
A design decision was made early in the EDK II project to not depend on any
compiler intrinsic functions. The reasons include:
1) Linking against OS specific C libs has risks because it can potentially
introduce OS specific sys calls.
2) Linking against OS specific C libs can potentially produce larger
firmware images.
3) Different compilers and each compiler release can choose to
add/remove/modify intrinsic functions the compiler generates to meet that
specific compiler’s requirements.
4) Not all intrinsic functions generated by all compilers are fully
documented.
When the AppPkg and support for C lib was added, there was a new requirement to
support building exiting C application sources “as is”. This meant that some
intrinsic functions could not be avoided, so the minimum set of intrinsic
functions were added to the C lib support and the C lib maintainer has to
handle the issues listed above. As a result, the compiler compatibility of the
AppPkg may not be the same as the rest of the EDK II packages.
I may be a good idea to move the just the intrinsic functions into their own
lib instances in the AppPkg, so they are available for linking against firmware
modules to work around porting issues until the intrinsic functions are
replaced with MdePkg lib calls.
Best regards,
Mike
From: Thomas Rognon [mailto:tcrog...@gmail.com]
Sent: Wednesday, August 20, 2014 11:34 AM
To: edk2-devel
Subject: Re: [edk2] [StdLib] Patch for review: Add VC++ helper function for
64-bit right shift
UefiCpuPkg/Library/CompilerIntrinsicsLib would be awesome. I feel like I'm
always battling the compiler with math and memory intrinsics. I hope this
happens.
On Wed, Aug 20, 2014 at 1:06 PM, Tim Lewis
<tim.le...@insyde.com<mailto:tim.le...@insyde.com>> wrote:
Daryl –
Do we want to create the equivalent of the ArmPkg/Library/CompilerIntrinsicsLib
for x86 so that these sorts of math-helpers can be used across the whole build?
Perhaps UefiCpuPkg/Library/CompilerIntrinsicsLib?
Tim
From: Mcdaniel, Daryl
[mailto:daryl.mcdan...@intel.com<mailto:daryl.mcdan...@intel.com>]
Sent: Wednesday, August 20, 2014 10:56 AM
To: edk2-devel@lists.sourceforge.net<mailto:edk2-devel@lists.sourceforge.net>
Subject: [edk2] [StdLib] Patch for review: Add VC++ helper function for 64-bit
right shift
Jaben, Erik, or Lee (or anyone else ☺),
Please review the attached patch. llshr.c is a new file, LibC.inf was modified.
StdLib: Add a runtime helper function for VC++ 64-bit right shift on Ia32
target architectures.
Add new file StdLib/LibC/CRT/Ia32/llshr.c
Add references to the new file to StdLib/LibC/LibC.inf
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Daryl McDaniel
<daryl.mcdan...@intel.com<mailto:daryl.mcdan...@intel.com>>
Reviewed-by:
Daryl McDaniel
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