9.40.5.4 literal

The .literal directive is used to define literal pool data, i.e., read-only 32-bit data accessed via L32R instructions.

         .literal label, value[, value...]

This directive is similar to the standard .word directive, except that the actual location of the literal data is determined by the assembler and linker, not by the position of the .literal directive. Using this directive gives the assembler freedom to locate the literal data in the most appropriate place and possibly to combine identical literals. For example, the code:

         entry sp, 40
         .literal .L1, sym
         l32r    a4, .L1

can be used to load a pointer to the symbol sym into register a4. The value of sym will not be placed between the ENTRY and L32R instructions; instead, the assembler puts the data in a literal pool.

Literal pools are placed by default in separate literal sections; however, when using the --text-section-literals option (see Command Line Options), the literal pools for PC-relative mode L32R instructions are placed in the current section.1 These text section literal pools are created automatically before ENTRY instructions and manually after .literal_position directives (see literal_position). If there are no preceding ENTRY instructions, explicit .literal_position directives must be used to place the text section literal pools; otherwise, as will report an error.

When literals are placed in separate sections, the literal section names are derived from the names of the sections where the literals are defined. The base literal section names are .literal for PC-relative mode L32R instructions and .lit4 for absolute mode L32R instructions (see absolute-literals). These base names are used for literals defined in the default .text section. For literals defined in other sections or within the scope of a literal_prefix directive (see literal_prefix), the following rules determine the literal section name:

  1. If the current section is a member of a section group, the literal section name includes the group name as a suffix to the base .literal or .lit4 name, with a period to separate the base name and group name. The literal section is also made a member of the group.
  2. If the current section name (or literal_prefix value) begins with “.gnu.linkonce.kind.”, the literal section name is formed by replacing “.kind” with the base .literal or .lit4 name. For example, for literals defined in a section named .gnu.linkonce.t.func, the literal section will be .gnu.linkonce.literal.func or .gnu.linkonce.lit4.func.
  3. If the current section name (or literal_prefix value) ends with .text, the literal section name is formed by replacing that suffix with the base .literal or .lit4 name. For example, for literals defined in a section named .iram0.text, the literal section will be .iram0.literal or .iram0.lit4.
  4. If none of the preceding conditions apply, the literal section name is formed by adding the base .literal or .lit4 name as a suffix to the current section name (or literal_prefix value).

Footnotes

[1] Literals for the .init and .fini sections are always placed in separate sections, even when --text-section-literals is enabled.