Re: [Patch V2] UefiCpuPkg/MpInitLib: Fix X64 XCODE5/NASM compatibility issues

[Andrew Fish <afish@apple.com>]

> On Jun 6, 2017, at 2:05 PM, hpa@zytor.com wrote:
> 
> On June 6, 2017 1:49:34 PM PDT, Andrew Fish <afish@apple.com> wrote:
>> 
>>> On Jun 6, 2017, at 12:41 PM, H. Peter Anvin <hpa@zytor.com> wrote:
>>> 
>>> On 05/22/17 19:08, Fan, Jeff wrote:
>>>> 
>>>> diff --git a/UefiCpuPkg/Library/MpInitLib/X64/MpFuncs.nasm
>> b/UefiCpuPkg/Library/MpInitLib/X64/MpFuncs.nasm
>>>> index fa54d01..0b14a53 100644
>>>> --- a/UefiCpuPkg/Library/MpInitLib/X64/MpFuncs.nasm
>>>> +++ b/UefiCpuPkg/Library/MpInitLib/X64/MpFuncs.nasm
>>>> @@ -1,5 +1,5 @@
>>>> 
>> ;------------------------------------------------------------------------------
>> ; -; Copyright (c) 2015 - 2016, Intel Corporation. All rights
>> reserved.<BR>
>>>> +; Copyright (c) 2015 - 2017, Intel Corporation. All rights 
>>>> +reserved.<BR>
>>>> ; This program and the accompanying materials  ; are licensed and
>> made available under the terms and conditions of the BSD License  ;
>> which accompanies this distribution.  The full text of the license may
>> be found at @@ -201,7 +201,7 @@ CProcedureInvoke:
>>>>    push       rbp
>>>>    mov        rbp, rsp
>>>> 
>>>> -    mov        rax, ASM_PFX(InitializeFloatingPointUnits)
>>>> +    mov        rax, qword [esi +
>> InitializeFloatingPointUnitsAddress]
>> 
>> Does nasm remove the need for the ASM_PFX() macro? That macro hides if
>> C is decorating with a _ prefix. 
>> 
>> Also given it is a #define (equ) why do we use camel case vs. all caps?
>> 
>> Thanks,
>> 
>> Andrew Fish
>> 
>>>>    sub        rsp, 20h
>>>>    call       rax               ; Call assembly function to
>> initialize FPU per UEFI spec
>>>>    add        rsp, 20h
>>> 
>>> FYI, the qword specifier is unnecessary since you are already
>> specifying
>>> rax.
>>> 
>>> However, why not simply drop the use of rax entirely and do:
>>> 
>>> 	call [esi + InitializeFloatingPointUnitsAddress]
>>> 
>>> (Also: is this *really* supposed to be esi and not rsi?  The former
>>> means a 32-bit address.)
>>> 
>>> 	-hpa
>>> _______________________________________________
>>> edk2-devel mailing list
>>> edk2-devel@lists.01.org
>>> https://lists.01.org/mailman/listinfo/edk2-devel
> 
> The NASM command-line option --prefix _ should do exactly that.

How does it know when to prefix the _? That could break dead stripping with the Xcode linker. L is used to imply local symbol, don't dead strip. 

Thanks,

Andrew Fish

> -- 
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