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| -rw-r--r-- | gas/ChangeLog | 8 | ||||
| -rw-r--r-- | gas/doc/c-xtensa.texi | 67 |
2 files changed, 47 insertions, 28 deletions
diff --git a/gas/ChangeLog b/gas/ChangeLog index 3fc0597..5f6c4e7 100644 --- a/gas/ChangeLog +++ b/gas/ChangeLog @@ -1,3 +1,11 @@ +2004-10-14 Bob Wilson <bob.wilson@acm.org> + + * 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. + 2004-10-12 Bob Wilson <bob.wilson@acm.org> * config/tc-xtensa.c (xtensa_frequency_pseudo): Use set_subseg_freq. diff --git a/gas/doc/c-xtensa.texi b/gas/doc/c-xtensa.texi index 5101d31..25065f8 100644 --- a/gas/doc/c-xtensa.texi +++ b/gas/doc/c-xtensa.texi @@ -54,9 +54,7 @@ Indicate to the assembler whether @code{L32R} instructions use absolute or PC-relative addressing. If the processor includes the absolute addressing option, the default is to use absolute @code{L32R} relocations. Otherwise, only the PC-relative @code{L32R} relocations -can be used. Literals referenced with absolute @code{L32R} relocations -are always placed in the @code{.lit4} section, independent of the -placement of PC-relative literals. +can be used. @item --target-align | --no-target-align @kindex --target-align @@ -616,17 +614,17 @@ can be used to load a pointer to the symbol @code{sym} into register the data in a literal pool. Literal pools for absolute mode @code{L32R} instructions -(@pxref{Absolute Literals Directive}) are always placed in the +(@pxref{Absolute Literals Directive}) are placed in a seperate @code{.lit4} section. By default literal pools for PC-relative mode -@code{L32R} instructions are placed in a separate section; however, when -using the @samp{--text-@-section-@-literals} option (@pxref{Xtensa -Options, ,Command Line Options}), the literal pools are placed in the -current section. These text section literal pools are created -automatically before @code{ENTRY} instructions and manually after -@samp{.literal_position} directives (@pxref{Literal Position Directive, -,literal_position}). If there are no preceding @code{ENTRY} -instructions, explicit @code{.literal_position} directives -must be used to place the text section literal pools; otherwise, +@code{L32R} instructions are placed in a separate @code{.literal} +section; however, when using the @samp{--text-@-section-@-literals} +option (@pxref{Xtensa Options, ,Command Line Options}), the literal +pools are placed in the current section. These text section literal +pools are created automatically before @code{ENTRY} instructions and +manually after @samp{.literal_position} directives (@pxref{Literal +Position Directive, ,literal_position}). If there are no preceding +@code{ENTRY} instructions, explicit @code{.literal_position} directives +must be used to place the text section literal pools; otherwise, @command{@value{AS}} will report an error. @node Literal Position Directive @@ -679,9 +677,6 @@ continue: The @code{literal_prefix} directive allows you to specify different sections to hold literals from different portions of an assembly file. -This directive only applies to literals referenced from PC-relative -@code{L32R} instructions; it has no effect for absolute literals -(@pxref{Absolute Literals Directive}). With this directive, a single assembly file can be used to generate code into multiple sections, including literals generated by the assembler. @@ -690,13 +685,34 @@ into multiple sections, including literals generated by the assembler. .end literal_prefix @end smallexample -For the code inside the delimited region, the assembler puts literals in -the section @code{@var{name}.literal}. If this section does not yet -exist, the assembler creates it. The @var{name} parameter is -optional. If @var{name} is not specified, the literal prefix is set to -the ``default'' for the file. This default is usually @code{.literal} -but can be changed with the @samp{--rename-section} command-line -argument. +By default the assembler places literal pools in sections separate from +the instructions, using the default literal section names of +@code{.literal} for PC-relative mode @code{L32R} instructions and +@code{.lit4} for absolute mode @code{L32R} instructions (@pxref{Absolute +Literals Directive}). The @code{literal_prefix} directive causes +different literal sections to be used for the code inside the delimited +region. The new literal sections are determined by including @var{name} +as a prefix to the default literal section names. If the @var{name} +argument is omitted, the literal sections revert to the defaults. This +directive has no effect when using the +@samp{--text-@-section-@-literals} option (@pxref{Xtensa Options, +,Command Line Options}). + +Except for two special cases, the assembler determines the new literal +sections by simply prepending @var{name} to the default section names, +resulting in @code{@var{name}.literal} and @code{@var{name}.lit4} +sections. The @code{literal_prefix} directive is often used with the +name of the current text section as the prefix argument. To facilitate +this usage, the assembler uses special case rules when it recognizes +@var{name} as a text section name. First, if @var{name} ends with +@code{.text}, that suffix is not included in the literal section name. +For example, if @var{name} is @code{.iram0.text}, then the literal +sections will be @code{.iram0.literal} and @code{.iram0.lit4}. Second, +if @var{name} begins with @code{.gnu.linkonce.t.}, then the literal +section names are formed by replacing the @code{.t} substring with +@code{.literal} and @code{.lit4}. For example, if @var{name} is +@code{.gnu.linkonce.t.func}, the literal sections will be +@code{.gnu.linkonce.literal.func} and @code{.gnu.linkonce.lit4.func}. @node Absolute Literals Directive @subsection absolute-literals @@ -721,11 +737,6 @@ To change the @code{L32R} mode, the program must write the to keep track of the mode and indicate to the assembler which mode is used in each region of code. -Literals referenced with absolute @code{L32R} instructions are always -placed in the @code{.lit4} section. PC-relative literals may be placed -in the current text section or in a separate literal section, as -described elsewhere (@pxref{Literal Directive}). - If the Xtensa configuration includes the absolute @code{L32R} addressing option, the default is to assume absolute @code{L32R} addressing unless the @samp{--no-@-absolute-@-literals} command-line option is specified. |