Re: [PATCH v3 17/17] [gdb/docs] sme: Document SME registers and features

[Eli Zaretskii <eliz@gnu.org>]

> Date: Fri, 19 May 2023 11:25:08 +0100
> From: Luis Machado via Gdb-patches <gdb-patches@sourceware.org>
> 
> Updates since v2:
> 
> - More adjustments based on reviews.
> - Fixed incorrect number of tile pseudo-registers.
> - Fixed naming of tile slice pseudo-registers.
> - More detail about SME and how gdb implements it.
> - Attempted to clarify the text a bit more.
> 
> Updates since v1:
> 
> - Made SME text more thorough.
> - Adjusted text based on upstream reviews.
> - Fixed documentation errors (missing itemization for SME registers).
> 
> Provide documentation for the SME feature and other information that
> should be useful for users that need to debug a SME-capable target.

Thanks.  This part of the patch has numerous inconsistencies in
letter-case and markup of register names, see below.

> +The @code{za} register state can be either active or inactive, if it is not in
> +use.

"@code{ZA}", upper-case.

> +@var{svl}: The streaming vector length, in bytes.  It defines the size of each
> +dimension of the 2-dimensional square @code{za} matrix.  The total size of
> +@code{za} is therefore @var{svl} by @var{svl}.

Same here.

> +The @code{za} register is a 2-dimensional square @var{svl} by @var{svl}

And here.

> +If the user wants to index the @code{za} register as a matrix, it is possible
> +to reference @code{za} as @code{za[@var{i}][@var{j}]}, where @var{i} is the
> +row number and @var{j} is the column number.

And here.

> +The @var{svg} register always contains the streaming vector granule
       ^^^^^^^^^
"@code{SVG}"

> +(@var{svg}) for the current thread.  From @var{svg} we can easily derive

Same here.

> +The @code{svcr} pseudo-register (streaming vector control register) is a status

Same here: "@code{SVCR}"

> +If the @sc{za} bit is 1, it means the @code{za} register is being used and
                                         ^^^^^^^^^
"@code{ZA}", upper-case.

> +For convenience and simplicity, if the @sc{za} bit is 0, the @code{za}
> +register and all of its pseudo-registers will read as zero.

Same here.

> +If @var{svl} changes during the execution of a program, then the @code{za}
> +register size and the bits in the @code{svcr} pseudo-register will be updated
> +to reflect it.

And here.

> +It is possible for users to change @var{svl} during the execution of a
> +program by modifying the @var{svg} register value.
                            ^^^^^^^^^
"@code{SVG}"

> +Whenever the @var{svg} register is modified with a new value, the

Same here.

> +@item The @code{za} register will have a new size and its state will be

"@code{ZA}"

> +@sc{sm} bit was 0 prior to modifying the @var{svg} register, there will be no
                                            ^^^^^^^^^
"@code{SVG}"

> +The possible values for the @var{svg} register are 2, 4, 8, 16, 32.  These

Same here.

> +The minimum size of the @code{za} register is 16 x 16 (256) bytes, and the

"@code{ZA}"

> +maximum size is 256 x 256 (65536) bytes.  In streaming mode, with bit @sc{sm}
> +set, the size of the @code{za} register is the size of all the SVE @code{z}

Same here, and also "@code{Z}", upper-case.

> +The @code{za} register can also be accessed using tiles and tile slices.

"@code{ZA}"

> +Tile pseudo-registers are square, 2-dimensional sub-arrays of elements within
> +the @code{za} register.

Same here.

> +There is a total of 31 @code{za} tile pseudo-registers.  They are
> +@code{za0b}, @code{za0h} through @code{za1h}, @code{zas0} through @code{zas3},
> +@code{zad0} through @code{zad7} and @code{zaq0} through @code{zaq15}.

Same here: all the register names should be in upper-case.

> +Tile slice pseudo-registers are vectors of horizontally or vertically
> +contiguous elements within the @code{za} register.

"@code{ZA}"

> +The tile slice pseudo-registers have the following naming pattern:
> +@code{za<@var{tile number}><@var{direction}><@var{qualifier}>
> +<@var{slice number}>}.

Same here.

> +When listing all the available registers, users will see the
> +currently-available @code{za} pseudo-registers.  Pseudo-registers that don't

And here.

> +account the @code{svcr} pseudo-register bits nor the @code{za} register

And here.

> +contents. @xref{Calling}
           ^^
Two spaces there.

> +The @url{https://github.com/ARM-software/abi-aa/blob/main/aapcs64/aapcs64.rst#the-za-lazy-saving-scheme,
> +lazy saving scheme} involving the @code{tpidr2} register is not yet supported
> +by @value{GDBN}, though the @code{tpidr2} register is known and supported
> +by @value{GDBN}.

Please up-case the names of the registers here.

> +@value{GDBN} showing incorrect values for the @code{za} register and

"@code{ZA}"

> +The @samp{org.gnu.gdb.aarch64.sme} feature is optional.  If present,
> +it should contain registers @samp{za}, @samp{svg} and @samp{svcr}.

Since you use @code, not @samp, for register markup elsewhere, please
use @code here as well.  Also, please up-case the names of the
registers.

> +@samp{za} is a register represented by a vector of @var{svl}x@var{svl}
   ^^^^^^^^^
"@code{ZA}"

> +@samp{svg} is a 64-bit register containing the value of @var{svg}.  @xref{svg}.
   ^^^^^^^^^^
"@code{SVG}"

> +@samp{svcr} is a 64-bit status pseudo-register with two valid bits.  Bit 0
   ^^^^^^^^^^^
"@code{SVCR}"

> +Bit 1 (@sc{za}) shows whether the @code{za} register state is active (in use) or
                                     ^^^^^^^^^
"@code{ZA}"

> +The rest of the unused bits of the @samp{svcr} pseudo-register is undefined
                                      ^^^^^^^^^^^
"@code{SVCR}"

Reviewed-By: Eli Zaretskii <eliz@gnu.org>