* doc/c-xtensa.texi (Xtensa Options, Absolute Literals Directive):
Remove comments about placement of literal pools. (Literal Directive): Update description of literal placement. (Literal Prefix Directive): Remove statement that this does not apply to absolute-mode literals. Describe new section naming scheme.
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Bob Wilson
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@ -1,3 +1,11 @@
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2004-10-14 Bob Wilson <bob.wilson@acm.org>
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* doc/c-xtensa.texi (Xtensa Options, Absolute Literals Directive):
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Remove comments about placement of literal pools.
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(Literal Directive): Update description of literal placement.
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(Literal Prefix Directive): Remove statement that this does not apply
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to absolute-mode literals. Describe new section naming scheme.
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2004-10-12 Bob Wilson <bob.wilson@acm.org>
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* config/tc-xtensa.c (xtensa_frequency_pseudo): Use set_subseg_freq.
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@ -54,9 +54,7 @@ Indicate to the assembler whether @code{L32R} instructions use absolute
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or PC-relative addressing. If the processor includes the absolute
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addressing option, the default is to use absolute @code{L32R}
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relocations. Otherwise, only the PC-relative @code{L32R} relocations
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can be used. Literals referenced with absolute @code{L32R} relocations
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are always placed in the @code{.lit4} section, independent of the
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placement of PC-relative literals.
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can be used.
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@item --target-align | --no-target-align
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@kindex --target-align
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@ -616,17 +614,17 @@ can be used to load a pointer to the symbol @code{sym} into register
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the data in a literal pool.
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Literal pools for absolute mode @code{L32R} instructions
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(@pxref{Absolute Literals Directive}) are always placed in the
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(@pxref{Absolute Literals Directive}) are placed in a seperate
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@code{.lit4} section. By default literal pools for PC-relative mode
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@code{L32R} instructions are placed in a separate section; however, when
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using the @samp{--text-@-section-@-literals} option (@pxref{Xtensa
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Options, ,Command Line Options}), the literal pools are placed in the
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current section. These text section literal pools are created
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automatically before @code{ENTRY} instructions and manually after
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@samp{.literal_position} directives (@pxref{Literal Position Directive,
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,literal_position}). If there are no preceding @code{ENTRY}
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instructions, explicit @code{.literal_position} directives
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must be used to place the text section literal pools; otherwise,
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@code{L32R} instructions are placed in a separate @code{.literal}
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section; however, when using the @samp{--text-@-section-@-literals}
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option (@pxref{Xtensa Options, ,Command Line Options}), the literal
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pools are placed in the current section. These text section literal
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pools are created automatically before @code{ENTRY} instructions and
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manually after @samp{.literal_position} directives (@pxref{Literal
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Position Directive, ,literal_position}). If there are no preceding
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@code{ENTRY} instructions, explicit @code{.literal_position} directives
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must be used to place the text section literal pools; otherwise,
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@command{@value{AS}} will report an error.
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@node Literal Position Directive
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@ -679,9 +677,6 @@ continue:
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The @code{literal_prefix} directive allows you to specify different
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sections to hold literals from different portions of an assembly file.
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This directive only applies to literals referenced from PC-relative
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@code{L32R} instructions; it has no effect for absolute literals
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(@pxref{Absolute Literals Directive}).
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With this directive, a single assembly file can be used to generate code
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into multiple sections, including literals generated by the assembler.
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@ -690,13 +685,34 @@ into multiple sections, including literals generated by the assembler.
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.end literal_prefix
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@end smallexample
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For the code inside the delimited region, the assembler puts literals in
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the section @code{@var{name}.literal}. If this section does not yet
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exist, the assembler creates it. The @var{name} parameter is
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optional. If @var{name} is not specified, the literal prefix is set to
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the ``default'' for the file. This default is usually @code{.literal}
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but can be changed with the @samp{--rename-section} command-line
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argument.
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By default the assembler places literal pools in sections separate from
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the instructions, using the default literal section names of
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@code{.literal} for PC-relative mode @code{L32R} instructions and
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@code{.lit4} for absolute mode @code{L32R} instructions (@pxref{Absolute
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Literals Directive}). The @code{literal_prefix} directive causes
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different literal sections to be used for the code inside the delimited
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region. The new literal sections are determined by including @var{name}
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as a prefix to the default literal section names. If the @var{name}
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argument is omitted, the literal sections revert to the defaults. This
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directive has no effect when using the
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@samp{--text-@-section-@-literals} option (@pxref{Xtensa Options,
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,Command Line Options}).
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Except for two special cases, the assembler determines the new literal
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sections by simply prepending @var{name} to the default section names,
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resulting in @code{@var{name}.literal} and @code{@var{name}.lit4}
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sections. The @code{literal_prefix} directive is often used with the
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name of the current text section as the prefix argument. To facilitate
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this usage, the assembler uses special case rules when it recognizes
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@var{name} as a text section name. First, if @var{name} ends with
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@code{.text}, that suffix is not included in the literal section name.
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For example, if @var{name} is @code{.iram0.text}, then the literal
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sections will be @code{.iram0.literal} and @code{.iram0.lit4}. Second,
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if @var{name} begins with @code{.gnu.linkonce.t.}, then the literal
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section names are formed by replacing the @code{.t} substring with
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@code{.literal} and @code{.lit4}. For example, if @var{name} is
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@code{.gnu.linkonce.t.func}, the literal sections will be
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@code{.gnu.linkonce.literal.func} and @code{.gnu.linkonce.lit4.func}.
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@node Absolute Literals Directive
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@subsection absolute-literals
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@ -721,11 +737,6 @@ To change the @code{L32R} mode, the program must write the
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to keep track of the mode and indicate to the assembler which mode is
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used in each region of code.
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Literals referenced with absolute @code{L32R} instructions are always
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placed in the @code{.lit4} section. PC-relative literals may be placed
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in the current text section or in a separate literal section, as
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described elsewhere (@pxref{Literal Directive}).
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If the Xtensa configuration includes the absolute @code{L32R} addressing
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option, the default is to assume absolute @code{L32R} addressing unless
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the @samp{--no-@-absolute-@-literals} command-line option is specified.
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