> -----Original Message----- > From: Leif Lindholm [mailto:[email protected]] > Sent: 15 September 2017 17:06 > To: Evan Lloyd <[email protected]> > Cc: [email protected]; Ard Biesheuvel <[email protected]>; > Matteo Carlini <[email protected]>; Sami Mujawar > <[email protected]> > Subject: Re: [PATCH] ArmPkg: ARM v8.2 updates for detecting FP > > On Thu, Sep 14, 2017 at 05:11:21PM +0100, [email protected] wrote: > > From: Sami Mujawar <samimujawar> > > I have fixed Sami's email address up before pushing.
[[Evan Lloyd]] Thanks, Leif. That was a problem caused by an out of date config in the original repo where the change was created. Sami has fixed any others in our internal repo, so it shouldn't happen again. > > > The ARMv8.2-FP16 extension introduces support for half precision > > floating point and the processor ID registers have been updated to > > enable detection of the implementation. > > > > The possible values for the FP bits in ID_AA64PFR0_EL1[19:16] are: > > - 0000 : Floating-point is implemented. > > - 0001 : Floating-point including Half-precision support is > > implemented. > > - 1111 : Floating-point is not implemented. > > - All other values are reserved. > > > > Previously ArmEnableVFP() compared the FP bits with 0000b to see if > > the FP was implemented, before enabling FP. Modified this check to > > enable the FP if the FP bits 19:16 are not 1111b. > > > > Contributed-under: TianoCore Contribution Agreement 1.1 > > Signed-off-by: Sami Mujawar <[email protected]> > > Signed-off-by: Evan Lloyd <[email protected]> > > So ... I think longer-term we should try to move a lot of this type of stuff > to c > instead, but this is a clear fix - thanks! [[Evan Lloyd]] You are most welcome. We agree about the move to c, as assembler code doesn't buy anything here. However, if you are going to change that you probably have to do all of it - not a task I'd want to take on. > > Reviewed-by: Leif Lindholm <[email protected]> Pushed as > 2f16993c25 > > > --- > > ArmPkg/Library/ArmLib/AArch64/AArch64Support.S | 10 ++++++---- > > 1 file changed, 6 insertions(+), 4 deletions(-) > > > > diff --git a/ArmPkg/Library/ArmLib/AArch64/AArch64Support.S > > b/ArmPkg/Library/ArmLib/AArch64/AArch64Support.S > > index > > > dde6a756528f3abf1bd5a142448e42122a9bd8fa..2d136d242b943fe2f365bc82 > 4953 > > b7fe10c944b7 100644 > > --- a/ArmPkg/Library/ArmLib/AArch64/AArch64Support.S > > +++ b/ArmPkg/Library/ArmLib/AArch64/AArch64Support.S > > @@ -1,7 +1,7 @@ > > > > #--------------------------------------------------------------------- > > --------- > > # > > # Copyright (c) 2008 - 2010, Apple Inc. All rights reserved.<BR> -# > > Copyright (c) 2011 - 2014, ARM Limited. All rights reserved. > > +# Copyright (c) 2011 - 2017, ARM Limited. All rights reserved. > > # Copyright (c) 2016, Linaro Limited. All rights reserved. > > # > > # This program and the accompanying materials @@ -403,9 +403,11 @@ > > ASM_FUNC(ArmEnableVFP) > > mov x1, x30 // Save LR > > bl ArmReadIdPfr0 // Read EL1 Processor Feature Register > > (PFR0) > > mov x30, x1 // Restore LR > > - ands x0, x0, #AARCH64_PFR0_FP// Extract bits indicating VFP > implementation > > - cmp x0, #0 // VFP is implemented if '0'. > > - b.ne 4f // Exit if VFP not implemented. > > + ubfx x0, x0, #16, #4 // Extract the FP bits 16:19 > > + cmp x0, #0xF // Check if FP bits are '1111b', > > + // i.e. Floating Point not implemented > > + b.eq 4f // Exit when VFP is not implemented. > > + > > // FVP is implemented. > > // Make sure VFP exceptions are not trapped (to any exception level). > > mrs x0, cpacr_el1 // Read EL1 Coprocessor Access Control > > Register > (CPACR) > > -- > > Guid("CE165669-3EF3-493F-B85D-6190EE5B9759") > > IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you. _______________________________________________ edk2-devel mailing list [email protected] https://lists.01.org/mailman/listinfo/edk2-devel
