* PIC:: Macros for position independent code.
* Assembler Format:: Defining how to write insns and pseudo-ops to output.
* Debugging Info:: Defining the format of debugging output.
-* Cross-compilation:: Handling floating point for cross-compilers.
+* Floating Point:: Handling floating point for cross-compilers.
* Mode Switching:: Insertion of mode-switching instructions.
* Target Attributes:: Defining target-specific uses of @code{__attribute__}.
+* MIPS Coprocessors:: MIPS coprocessor support and how to customize it.
* Misc:: Everything else.
@end menu
than C@. If you do not define this macro, then the value of
@code{CPP_SPEC} (if any) will be used instead.
-@findex NO_BUILTIN_SIZE_TYPE
-@item NO_BUILTIN_SIZE_TYPE
-If this macro is defined, the preprocessor will not define the built-in macro
-@code{__SIZE_TYPE__}. The macro @code{__SIZE_TYPE__} must then be defined
-by @code{CPP_SPEC} instead.
-
-This should be defined if @code{SIZE_TYPE} depends on target dependent flags
-which are not accessible to the preprocessor. Otherwise, it should not
-be defined.
-
-@findex NO_BUILTIN_PTRDIFF_TYPE
-@item NO_BUILTIN_PTRDIFF_TYPE
-If this macro is defined, the preprocessor will not define the built-in macro
-@code{__PTRDIFF_TYPE__}. The macro @code{__PTRDIFF_TYPE__} must then be
-defined by @code{CPP_SPEC} instead.
-
-This should be defined if @code{PTRDIFF_TYPE} depends on target dependent flags
-which are not accessible to the preprocessor. Otherwise, it should not
-be defined.
-
-@findex NO_BUILTIN_WCHAR_TYPE
-@item NO_BUILTIN_WCHAR_TYPE
-If this macro is defined, the preprocessor will not define the built-in macro
-@code{__WCHAR_TYPE__}. The macro @code{__WCHAR_TYPE__} must then be
-defined by @code{CPP_SPEC} instead.
-
-This should be defined if @code{WCHAR_TYPE} depends on target dependent flags
-which are not accessible to the preprocessor. Otherwise, it should not
-be defined.
-
-@findex NO_BUILTIN_WINT_TYPE
-@item NO_BUILTIN_WINT_TYPE
-If this macro is defined, the preprocessor will not define the built-in macro
-@code{__WINT_TYPE__}. The macro @code{__WINT_TYPE__} must then be
-defined by @code{CPP_SPEC} instead.
-
-This should be defined if @code{WINT_TYPE} depends on target dependent flags
-which are not accessible to the preprocessor. Otherwise, it should not
-be defined.
-
@findex CC1_SPEC
@item CC1_SPEC
A C string constant that tells the GCC driver program options to
This macro is similar to @code{LINK_LIBGCC_SPECIAL}, except that it does
not affect @option{-L} options.
+@findex LINK_GCC_C_SEQUENCE_SPEC
+@item LINK_GCC_C_SEQUENCE_SPEC
+The sequence in which libgcc and libc are specified to the linker.
+By default this is @code{%G %L %G}.
+
@findex LINK_COMMAND_SPEC
@item LINK_COMMAND_SPEC
A C string constant giving the complete command line need to execute the
change is made to the link command line within @file{gcc.c}. Therefore,
define this macro only if you need to completely redefine the command
line for invoking the linker and there is no other way to accomplish
-the effect you need.
+the effect you need. Overriding this macro may be avoidable by overriding
+@code{LINK_GCC_C_SEQUENCE_SPEC} instead.
@findex LINK_ELIMINATE_DUPLICATE_LDIRECTORIES
@item LINK_ELIMINATE_DUPLICATE_LDIRECTORIES
Here are run-time target specifications.
@table @code
+@findex TARGET_CPU_CPP_BUILTINS
+@item TARGET_CPU_CPP_BUILTINS()
+This function-like macro expands to a block of code that defines
+built-in preprocessor macros and assertions for the target cpu, using
+the functions @code{builtin_macro}, @code{builtin_macro_std} and
+@code{builtin_assert} declared in @file{c-lex.h}. When the front end
+calls this macro it provides a trailing semicolon, and since it has
+finished command line option processing your code can use those
+results freely.
+
+@code{builtin_assert} takes a string in the form you pass to the
+command-line option @option{-A}, such as @code{cpu=mips}, and creates
+the assertion. @code{builtin_macro} takes a string in the form
+accepted by option @option{-D} and unconditionally defines the macro.
+
+@code{builtin_macro_std} takes a string representing the name of an
+object-like macro. If it doesn't lie in the user's namespace,
+@code{builtin_macro_std} defines it unconditionally. Otherwise, it
+defines a version with two leading underscores, and another version
+with two leading and trailing underscores, and defines the original
+only if an ISO standard was not requested on the command line. For
+example, passing @code{unix} defines @code{__unix}, @code{__unix__}
+and possibly @code{unix}; passing @code{_mips} defines @code{__mips},
+@code{__mips__} and possibly @code{_mips}, and passing @code{_ABI64}
+defines only @code{_ABI64}.
+
+With @code{TARGET_OS_CPP_BUILTINS} this macro obsoletes the
+@code{CPP_PREDEFINES} target macro.
+
+@findex TARGET_OS_CPP_BUILTINS
+@item TARGET_OS_CPP_BUILTINS()
+Similarly to @code{TARGET_CPU_CPP_BUILTINS} but this macro is optional
+and is used for the target operating system instead.
+
+With @code{TARGET_CPU_CPP_BUILTINS} this macro obsoletes the
+@code{CPP_PREDEFINES} target macro.
+
@findex CPP_PREDEFINES
@item CPP_PREDEFINES
Define this to be a string constant containing @option{-D} options to
for that option, but it will not count as an undocumented option. The
actual option name is made by appending @samp{-m} to the specified name.
Non-empty description strings should be marked with @code{N_(@dots{})} for
-@command{xgettext}. In addition to the description for @option{--help},
+@command{xgettext}. Please do not mark empty strings because the empty
+string is reserved by GNU gettext. @code{gettext("")} returns the header entry
+of the message catalog with meta information, not the empty string.
+
+In addition to the description for @option{--help},
more detailed documentation for each option should be added to
@file{invoke.texi}.
subgrouping for each command option.
Each subgrouping contains a string constant, that defines the fixed part
-of the option name, the address of a variable, and a description string
-(which should again be marked with @code{N_(@dots{})}).
+of the option name, the address of a variable, and a description string.
+Non-empty description strings should be marked with @code{N_(@dots{})} for
+@command{xgettext}. Please do not mark empty strings because the empty
+string is reserved by GNU gettext. @code{gettext("")} returns the header entry
+of the message catalog with meta information, not the empty string.
+
The variable, type @code{char *}, is set to the variable part of the
given option if the fixed part matches. The actual option name is made
by appending @samp{-m} to the specified name. Again, each option should
@findex BITS_PER_UNIT
@item BITS_PER_UNIT
Define this macro to be the number of bits in an addressable storage
-unit (byte); normally 8.
+unit (byte). If you do not define this macro the default is 8.
@findex BITS_PER_WORD
@item BITS_PER_WORD
-Number of bits in a word; normally 32.
+Number of bits in a word. If you do not define this macro, the default
+is @code{BITS_PER_UNIT * UNITS_PER_WORD}.
@findex MAX_BITS_PER_WORD
@item MAX_BITS_PER_WORD
@item POINTER_SIZE
Width of a pointer, in bits. You must specify a value no wider than the
width of @code{Pmode}. If it is not equal to the width of @code{Pmode},
-you must define @code{POINTERS_EXTEND_UNSIGNED}.
+you must define @code{POINTERS_EXTEND_UNSIGNED}. If you do not specify
+a value the default is @code{BITS_PER_WORD}.
@findex POINTERS_EXTEND_UNSIGNED
@item POINTERS_EXTEND_UNSIGNED
@findex BITFIELD_NBYTES_LIMITED
@item BITFIELD_NBYTES_LIMITED
-Like PCC_BITFIELD_TYPE_MATTERS except that its effect is limited to
-aligning a bit-field within the structure.
+Like @code{PCC_BITFIELD_TYPE_MATTERS} except that its effect is limited
+to aligning a bit-field within the structure.
@findex MEMBER_TYPE_FORCES_BLK
@item MEMBER_TYPE_FORCES_BLK (@var{field})
The ordering of the component words of floating point values stored in
memory is controlled by @code{FLOAT_WORDS_BIG_ENDIAN}.
+@findex MODE_HAS_NANS
+@item MODE_HAS_NANS (@var{mode})
+When defined, this macro should be true if @var{mode} has a NaN
+representation. The compiler assumes that NaNs are not equal to
+anything (including themselves) and that addition, subtraction,
+multiplication and division all return NaNs when one operand is
+NaN@.
+
+By default, this macro is true if @var{mode} is a floating-point
+mode and the target floating-point format is IEEE@.
+
+@findex MODE_HAS_INFINITIES
+@item MODE_HAS_INFINITIES (@var{mode})
+This macro should be true if @var{mode} can represent infinity. At
+present, the compiler uses this macro to decide whether @samp{x - x}
+is always defined. By default, the macro is true when @var{mode}
+is a floating-point mode and the target format is IEEE@.
+
+@findex MODE_HAS_SIGNED_ZEROS
+@item MODE_HAS_SIGNED_ZEROS (@var{mode})
+True if @var{mode} distinguishes between positive and negative zero.
+The rules are expected to follow the IEEE standard:
+
+@itemize @bullet
+@item
+@samp{x + x} has the same sign as @samp{x}.
+
+@item
+If the sum of two values with opposite sign is zero, the result is
+positive for all rounding modes expect towards @minus{}infinity, for
+which it is negative.
+
+@item
+The sign of a product or quotient is negative when exactly one
+of the operands is negative.
+@end itemize
+
+The default definition is true if @var{mode} is a floating-point
+mode and the target format is IEEE@.
+
+@findex MODE_HAS_SIGN_DEPENDENT_ROUNDING
+@item MODE_HAS_SIGN_DEPENDENT_ROUNDING (@var{mode})
+If defined, this macro should be true for @var{mode} if it has at
+least one rounding mode in which @samp{x} and @samp{-x} can be
+rounded to numbers of different magnitude. Two such modes are
+towards @minus{}infinity and towards +infinity.
+
+The default definition of this macro is true if @var{mode} is
+a floating-point mode and the target format is IEEE@.
+
+@findex ROUND_TOWARDS_ZERO
+@item ROUND_TOWARDS_ZERO
+If defined, this macro should be true if the prevailing rounding
+mode is towards zero. A true value has the following effects:
+
+@itemize @bullet
+@item
+@code{MODE_HAS_SIGN_DEPENDENT_ROUNDING} will be false for all modes.
+
+@item
+@file{libgcc.a}'s floating-point emulator will round towards zero
+rather than towards nearest.
+
+@item
+The compiler's floating-point emulator will round towards zero after
+doing arithmetic, and when converting from the internal float format to
+the target format.
+@end itemize
+
+The macro does not affect the parsing of string literals. When the
+primary rounding mode is towards zero, library functions like
+@code{strtod} might still round towards nearest, and the compiler's
+parser should behave like the target's @code{strtod} where possible.
+
+Not defining this macro is equivalent to returning zero.
+
+@findex LARGEST_EXPONENT_IS_NORMAL
+@item LARGEST_EXPONENT_IS_NORMAL (@var{size})
+This macro should only be defined when the target float format is
+described as IEEE@. It should return true if floats with @var{size}
+bits do not have a NaN or infinity representation, but use the largest
+exponent for normal numbers instead.
+
+Defining this macro to true for @var{size} causes @code{MODE_HAS_NANS}
+and @code{MODE_HAS_INFINITIES} to be false for @var{size}-bit modes.
+It also affects the way @file{libgcc.a} and @file{real.c} emulate
+floating-point arithmetic.
+
+The default definition of this macro returns false for all sizes.
@end table
+@deftypefn {Target Hook} bool TARGET_MS_BITFIELD_LAYOUT_P (tree @var{record_type})
+This target hook returns @code{true} if bit-fields in the given
+@var{record_type} are to be laid out following the rules of Microsoft
+Visual C/C++, namely: (i) a bit-field won't share the same storage
+unit with the previous bit-field if their underlying types have
+different sizes, and the bit-field will be aligned to the highest
+alignment of the underlying types of itself and of the previous
+bit-field; (ii) a zero-sized bit-field will affect the alignment of
+the whole enclosing structure, even if it is unnamed; except that
+(iii) a zero-sized bit-field will be disregarded unless it follows
+another bit-field of non-zero size. If this hook returns @code{true},
+other macros that control bit-field layout are ignored.
+@end deftypefn
+
@node Type Layout
@section Layout of Source Language Data Types
target machine. If you don't define this, the default is
@code{BITS_PER_UNIT}.
-@findex MAX_CHAR_TYPE_SIZE
-@item MAX_CHAR_TYPE_SIZE
-Maximum number for the size in bits of the type @code{char} on the
-target machine. If this is undefined, the default is
-@code{CHAR_TYPE_SIZE}. Otherwise, it is the constant value that is the
-largest value that @code{CHAR_TYPE_SIZE} can have at run-time. This is
-used in @code{cpp}.
-
@findex BOOL_TYPE_SIZE
@item BOOL_TYPE_SIZE
-A C expression for the size in bits of the C++ type @code{bool} on the
-target machine. If you don't define this, the default is
-@code{CHAR_TYPE_SIZE}.
+A C expression for the size in bits of the C++ type @code{bool} and
+C99 type @code{_Bool} on the target machine. If you don't define
+this, and you probably shouldn't, the default is @code{CHAR_TYPE_SIZE}.
@findex FLOAT_TYPE_SIZE
@item FLOAT_TYPE_SIZE
@findex TARGET_VTABLE_USES_DESCRIPTORS
@item TARGET_VTABLE_USES_DESCRIPTORS
Normally, the C++ compiler uses function pointers in vtables. This
-macro allows the target to change to use ``function descriptors''
+macro allows the target to change to use ``function descriptors''
instead. Function descriptors are found on targets for whom a
function pointer is actually a small data structure. Normally the
-data structure consists of the actual code address plus a data
+data structure consists of the actual code address plus a data
pointer to which the function's data is relative.
If vtables are used, the value of this macro should be the number
@cindex call-used register
@cindex call-clobbered register
@cindex call-saved register
-Like @code{CALL_USED_REGISTERS} except this macro doesn't require
-that the entire set of @code{FIXED_REGISTERS} be included.
+Like @code{CALL_USED_REGISTERS} except this macro doesn't require
+that the entire set of @code{FIXED_REGISTERS} be included.
(@code{CALL_USED_REGISTERS} must be a superset of @code{FIXED_REGISTERS}).
-This macro is optional. If not specified, it defaults to the value
+This macro is optional. If not specified, it defaults to the value
of @code{CALL_USED_REGISTERS}.
@findex HARD_REGNO_CALL_PART_CLOBBERED
for the address of the code being executed and @code{context->cfa} for
the stack pointer value. If the frame can be decoded, the register save
addresses should be updated in @var{fs} and the macro should branch to
-@var{success}. If the frame cannot be decoded, the macro should do
+@var{success}. If the frame cannot be decoded, the macro should do
nothing.
@end table
nothing (the caller pops all). When this convention is in use,
@var{funtype} is examined to determine whether a function takes a fixed
number of arguments.
+
+@findex CALL_POPS_ARGS
+@item CALL_POPS_ARGS (@var{cum})
+A C expression that should indicate the number of bytes a call sequence
+pops off the stack. It is added to the value of @code{RETURN_POPS_ARGS}
+when compiling a function call.
+
+@var{cum} is the variable in which all arguments to the called function
+have been accumulated.
+
+On certain architectures, such as the SH5, a call trampoline is used
+that pops certain registers off the stack, depending on the arguments
+that have been passed to the function. Since this is a property of the
+call site, not of the called function, @code{RETURN_POPS_ARGS} is not
+appropriate.
+
@end table
@node Register Arguments
values---values that can fit in registers.
@table @code
-@findex TRADITIONAL_RETURN_FLOAT
-@item TRADITIONAL_RETURN_FLOAT
-Define this macro if @option{-traditional} should not cause functions
-declared to return @code{float} to convert the value to @code{double}.
-
@findex FUNCTION_VALUE
@item FUNCTION_VALUE (@var{valtype}, @var{func})
A C expression to create an RTX representing the place where a
used by the epilogue or the @samp{return} pattern. The stack and frame
pointer registers are already be assumed to be used as needed.
+@findex EH_USES
+@item EH_USES (@var{regno})
+Define this macro as a C expression that is nonzero for registers that are
+used by the exception handling mechanism, and so should be considered live
+on entry to an exception edge.
+
@findex DELAY_SLOTS_FOR_EPILOGUE
@item DELAY_SLOTS_FOR_EPILOGUE
Define this macro if the function epilogue contains delay slots to which
them: try the first ones in this list first.
@deftypefn {Target Hook} int TARGET_SCHED_ISSUE_RATE (void)
-This hook returns the maximum number of instructions that can ever issue
-at the same time on the target machine. The default is one. This value
-must be constant over the entire compilation. If you need it to vary
-depending on what the instructions are, you must use
+This hook returns the maximum number of instructions that can ever
+issue at the same time on the target machine. The default is one.
+Although the insn scheduler can define itself the possibility of issue
+an insn on the same cycle, the value can serve as an additional
+constraint to issue insns on the same simulated processor cycle (see
+hooks @samp{TARGET_SCHED_REORDER} and @samp{TARGET_SCHED_REORDER2}).
+This value must be constant over the entire compilation. If you need
+it to vary depending on what the instructions are, you must use
@samp{TARGET_SCHED_VARIABLE_ISSUE}.
+
+You could use the value of macro @samp{MAX_DFA_ISSUE_RATE} to return
+the value of the hook @samp{TARGET_SCHED_ISSUE_RATE} for the automaton
+based pipeline interface.
@end deftypefn
@deftypefn {Target Hook} int TARGET_SCHED_VARIABLE_ISSUE (FILE *@var{file}, int @var{verbose}, rtx @var{insn}, int @var{more})
@end deftypefn
@deftypefn {Target Hook} int TARGET_SCHED_ADJUST_COST (rtx @var{insn}, rtx @var{link}, rtx @var{dep_insn}, int @var{cost})
-This function corrects the value of @var{cost} based on the relationship
-between @var{insn} and @var{dep_insn} through the dependence @var{link}.
-It should return the new value. The default is to make no adjustment to
-@var{cost}. This can be used for example to specify to the scheduler
+This function corrects the value of @var{cost} based on the
+relationship between @var{insn} and @var{dep_insn} through the
+dependence @var{link}. It should return the new value. The default
+is to make no adjustment to @var{cost}. This can be used for example
+to specify to the scheduler using the traditional pipeline description
that an output- or anti-dependence does not incur the same cost as a
-data-dependence.
+data-dependence. If the scheduler using the automaton based pipeline
+description, the cost of anti-dependence is zero and the cost of
+output-dependence is maximum of one and the difference of latency
+times of the first and the second insns. If these values are not
+acceptable, you could use the hook to modify them too. See also
+@pxref{Automaton pipeline description}.
@end deftypefn
@deftypefn {Target Hook} int TARGET_SCHED_ADJUST_PRIORITY (rtx @var{insn}, int @var{priority})
@option{-fsched-verbose-@var{n}}.
@end deftypefn
-@deftypefn {Target Hook} rtx TARGET_SCHED_CYCLE_DISPLAY (int @var{clock}, rtx @var{last})
-This hook is called in verbose mode only, at the beginning of each pass
-over a basic block. It should insert an insn into the chain after
-@var{last}, which has no effect, but records the value @var{clock} in
-RTL dumps and assembly output. Define this hook only if you need this
-level of detail about what the scheduler is doing.
+@deftypefn {Target Hook} int TARGET_SCHED_USE_DFA_PIPELINE_INTERFACE (void)
+This hook is called many times during insn scheduling. If the hook
+returns nonzero, the automaton based pipeline description is used for
+insn scheduling. Otherwise the traditional pipeline description is
+used. The default is usage of the traditional pipeline description.
+
+You should also remember that to simplify the insn scheduler sources
+an empty traditional pipeline description interface is generated even
+if there is no a traditional pipeline description in the @file{.md}
+file. The same is true for the automaton based pipeline description.
+That means that you should be accurate in defining the hook.
+@end deftypefn
+
+@deftypefn {Target Hook} int TARGET_SCHED_DFA_PRE_CYCLE_INSN (void)
+The hook returns an RTL insn. The automaton state used in the
+pipeline hazard recognizer is changed as if the insn were scheduled
+when the new simulated processor cycle starts. Usage of the hook may
+simplify the automaton pipeline description for some @acronym{VLIW}
+processors. If the hook is defined, it is used only for the automaton
+based pipeline description. The default is not to change the state
+when the new simulated processor cycle starts.
+@end deftypefn
+
+@deftypefn {Target Hook} void TARGET_SCHED_INIT_DFA_PRE_CYCLE_INSN (void)
+The hook can be used to initialize data used by the previous hook.
+@end deftypefn
+
+@deftypefn {Target Hook} int TARGET_SCHED_DFA_POST_CYCLE_INSN (void)
+The hook is analogous to @samp{TARGET_SCHED_DFA_PRE_CYCLE_INSN} but used
+to changed the state as if the insn were scheduled when the new
+simulated processor cycle finishes.
+@end deftypefn
+
+@deftypefn {Target Hook} void TARGET_SCHED_INIT_DFA_POST_CYCLE_INSN (void)
+The hook is analogous to @samp{TARGET_SCHED_INIT_DFA_PRE_CYCLE_INSN} but
+used to initialize data used by the previous hook.
+@end deftypefn
+
+@deftypefn {Target Hook} int TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD (void)
+This hook controls better choosing an insn from the ready insn queue
+for the @acronym{DFA}-based insn scheduler. Usually the scheduler
+chooses the first insn from the queue. If the hook returns a positive
+value, an additional scheduler code tries all permutations of
+@samp{TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD ()}
+subsequent ready insns to choose an insn whose issue will result in
+maximal number of issued insns on the same cycle. For the
+@acronym{VLIW} processor, the code could actually solve the problem of
+packing simple insns into the @acronym{VLIW} insn. Of course, if the
+rules of @acronym{VLIW} packing are described in the automaton.
+
+This code also could be used for superscalar @acronym{RISC}
+processors. Let us consider a superscalar @acronym{RISC} processor
+with 3 pipelines. Some insns can be executed in pipelines @var{A} or
+@var{B}, some insns can be executed only in pipelines @var{B} or
+@var{C}, and one insn can be executed in pipeline @var{B}. The
+processor may issue the 1st insn into @var{A} and the 2nd one into
+@var{B}. In this case, the 3rd insn will wait for freeing @var{B}
+until the next cycle. If the scheduler issues the 3rd insn the first,
+the processor could issue all 3 insns per cycle.
+
+Actually this code demonstrates advantages of the automaton based
+pipeline hazard recognizer. We try quickly and easy many insn
+schedules to choose the best one.
+
+The default is no multipass scheduling.
+@end deftypefn
+
+@deftypefn {Target Hook} void TARGET_SCHED_INIT_DFA_BUBBLES (void)
+The @acronym{DFA}-based scheduler could take the insertion of nop
+operations for better insn scheduling into account. It can be done
+only if the multi-pass insn scheduling works (see hook
+@samp{TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD}).
+
+Let us consider a @acronym{VLIW} processor insn with 3 slots. Each
+insn can be placed only in one of the three slots. We have 3 ready
+insns @var{A}, @var{B}, and @var{C}. @var{A} and @var{C} can be
+placed only in the 1st slot, @var{B} can be placed only in the 3rd
+slot. We described the automaton which does not permit empty slot
+gaps between insns (usually such description is simpler). Without
+this code the scheduler would place each insn in 3 separate
+@acronym{VLIW} insns. If the scheduler places a nop insn into the 2nd
+slot, it could place the 3 insns into 2 @acronym{VLIW} insns. What is
+the nop insn is returned by hook @samp{TARGET_SCHED_DFA_BUBBLE}. Hook
+@samp{TARGET_SCHED_INIT_DFA_BUBBLES} can be used to initialize or
+create the nop insns.
+
+You should remember that the scheduler does not insert the nop insns.
+It is not wise because of the following optimizations. The scheduler
+only considers such possibility to improve the result schedule. The
+nop insns should be inserted lately, e.g. on the final phase.
@end deftypefn
+@deftypefn {Target Hook} rtx TARGET_SCHED_DFA_BUBBLE (int @var{index})
+This hook @samp{FIRST_CYCLE_MULTIPASS_SCHEDULING} is used to insert
+nop operations for better insn scheduling when @acronym{DFA}-based
+scheduler makes multipass insn scheduling (see also description of
+hook @samp{TARGET_SCHED_INIT_DFA_BUBBLES}). This hook
+returns a nop insn with given @var{index}. The indexes start with
+zero. The hook should return @code{NULL} if there are no more nop
+insns with indexes greater than given index.
+@end deftypefn
+
+Macros in the following table are generated by the program
+@file{genattr} and can be useful for writing the hooks.
+
+@table @code
+@findex TRADITIONAL_PIPELINE_INTERFACE
+@item TRADITIONAL_PIPELINE_INTERFACE
+The macro definition is generated if there is a traditional pipeline
+description in @file{.md} file. You should also remember that to
+simplify the insn scheduler sources an empty traditional pipeline
+description interface is generated even if there is no a traditional
+pipeline description in the @file{.md} file. The macro can be used to
+distinguish the two types of the traditional interface.
+
+@findex DFA_PIPELINE_INTERFACE
+@item DFA_PIPELINE_INTERFACE
+The macro definition is generated if there is an automaton pipeline
+description in @file{.md} file. You should also remember that to
+simplify the insn scheduler sources an empty automaton pipeline
+description interface is generated even if there is no an automaton
+pipeline description in the @file{.md} file. The macro can be used to
+distinguish the two types of the automaton interface.
+
+@findex MAX_DFA_ISSUE_RATE
+@item MAX_DFA_ISSUE_RATE
+The macro definition is generated in the automaton based pipeline
+description interface. Its value is calculated from the automaton
+based pipeline description and is equal to maximal number of all insns
+described in constructions @samp{define_insn_reservation} which can be
+issued on the same processor cycle.
+
+@end table
+
@node Sections
@section Dividing the Output into Sections (Texts, Data, @dots{})
@c the above section title is WAY too long. maybe cut the part between
is enough. The MIPS port uses this to sort all functions after all data
declarations.
+@findex HOT_TEXT_SECTION_NAME
+@item HOT_TEXT_SECTION_NAME
+If defined, a C string constant for the name of the section containing most
+frequently executed functions of the program. If not defined, GCC will provide
+a default definition if the target supports named sections.
+
+@findex UNLIKELY_EXECUTED_TEXT_SECTION_NAME
+@item UNLIKELY_EXECUTED_TEXT_SECTION_NAME
+If defined, a C string constant for the name of the section containing unlikely
+executed functions in the program.
+
@findex DATA_SECTION_ASM_OP
@item DATA_SECTION_ASM_OP
A C expression whose value is a string, including spacing, containing the
assembler operation to identify the following data as writable initialized
data. Normally @code{"\t.data"} is right.
+@findex READONLY_DATA_SECTION_ASM_OP
+@item READONLY_DATA_SECTION_ASM_OP
+A C expression whose value is a string, including spacing, containing the
+assembler operation to identify the following data as read-only initialized
+data.
+
+@findex READONLY_DATA_SECTION
+@item READONLY_DATA_SECTION
+A macro naming a function to call to switch to the proper section for
+read-only data. The default is to use @code{READONLY_DATA_SECTION_ASM_OP}
+if defined, else fall back to @code{text_section}.
+
+The most common definition will be @code{data_section}, if the target
+does not have a special read-only data section, and does not put data
+in the text section.
+
@findex SHARED_SECTION_ASM_OP
@item SHARED_SECTION_ASM_OP
If defined, a C expression whose value is a string, including spacing,
@code{data_section}, for your additional sections. Do not define this
macro if you do not define @code{EXTRA_SECTIONS}.
-@findex READONLY_DATA_SECTION
-@item READONLY_DATA_SECTION
-On most machines, read-only variables, constants, and jump tables are
-placed in the text section. If this is not the case on your machine,
-this macro should be defined to be the name of a function (either
-@code{data_section} or a function defined in @code{EXTRA_SECTIONS}) that
-switches to the section to be used for read-only items.
-
-If these items should be placed in the text section, this macro should
-not be defined.
-
-@findex SELECT_SECTION
-@item SELECT_SECTION (@var{exp}, @var{reloc}, @var{align})
-A C statement or statements to switch to the appropriate section for
-output of @var{exp}. You can assume that @var{exp} is either a
-@code{VAR_DECL} node or a constant of some sort. @var{reloc}
-indicates whether the initial value of @var{exp} requires link-time
-relocations. Bit 1 is set when variable contains local relocations
-only, while bit 2 is set for global relocations.
-Select the section by calling @code{text_section} or one
-of the alternatives for other sections. @var{align} is the constant
-alignment in bits.
-
-Do not define this macro if you put all read-only variables and
-constants in the read-only data section (usually the text section).
-
-@findex SELECT_RTX_SECTION
-@item SELECT_RTX_SECTION (@var{mode}, @var{rtx}, @var{align})
-A C statement or statements to switch to the appropriate section for
-output of @var{rtx} in mode @var{mode}. You can assume that @var{rtx}
-is some kind of constant in RTL@. The argument @var{mode} is redundant
-except in the case of a @code{const_int} rtx. Select the section by
-calling @code{text_section} or one of the alternatives for other
-sections. @var{align} is the constant alignment in bits.
-
-Do not define this macro if you put all constants in the read-only
-data section.
-
@findex JUMP_TABLES_IN_TEXT_SECTION
@item JUMP_TABLES_IN_TEXT_SECTION
Define this macro to be an expression with a nonzero value if jump
This macro is irrelevant if there is no separate readonly data section.
@findex ENCODE_SECTION_INFO
-@item ENCODE_SECTION_INFO (@var{decl})
+@item ENCODE_SECTION_INFO (@var{decl}, @var{new_decl_p})
Define this macro if references to a symbol or a constant must be
treated differently depending on something about the variable or
function named by the symbol (such as what section it is in).
The macro definition, if any, is executed under two circumstances. One
is immediately after the rtl for @var{decl} that represents a variable
-or a function has been created and stored in @code{DECL_RTL
-(@var{decl})}. The value of the rtl will be a @code{mem} whose address
-is a @code{symbol_ref}. The other is immediately after the rtl for
-@var{decl} that represents a constant has been created and stored in
-@code{TREE_CST_RTL (@var{decl})}. The macro is called once for each
-distinct constant in a source file.
+or a function has been created and stored in @code{DECL_RTL(@var{decl})}.
+The value of the rtl will be a @code{mem} whose address is a @code{symbol_ref}.
+The other is immediately after the rtl for @var{decl} that represents a
+constant has been created and stored in @code{TREE_CST_RTL (@var{decl})}.
+The macro is called once for each distinct constant in a source file.
+
+The @var{new_decl_p} argument will be true if this is the first time that
+@code{ENCODE_SECTION_INFO} has been invoked on this decl. It will
+be false for subsequent invocations, which will happen for duplicate
+declarations. Whether or not anything must be done for the duplicate
+declaration depends on whether @code{ENCODE_SECTION_INFO} examines
+@code{DECL_ATTRIBUTES}.
@cindex @code{SYMBOL_REF_FLAG}, in @code{ENCODE_SECTION_INFO}
The usual thing for this macro to do is to record a flag in the
@code{symbol_ref} (such as @code{SYMBOL_REF_FLAG}) or to store a
-modified name string in the @code{symbol_ref} (if one bit is not enough
-information).
+modified name string in the @code{symbol_ref} (if one bit is not
+enough information).
@findex STRIP_NAME_ENCODING
@item STRIP_NAME_ENCODING (@var{var}, @var{sym_name})
Decode @var{sym_name} and store the real name part in @var{var}, sans
the characters that encode section info. Define this macro if
@code{ENCODE_SECTION_INFO} alters the symbol's name string.
-
-@findex UNIQUE_SECTION
-@item UNIQUE_SECTION (@var{decl}, @var{reloc})
-A C statement to build up a unique section name, expressed as a
-@code{STRING_CST} node, and assign it to @samp{DECL_SECTION_NAME (@var{decl})}.
-@var{reloc} indicates whether the initial value of @var{exp} requires
-link-time relocations. If you do not define this macro, GCC will use
-the symbol name prefixed by @samp{.} as the section name. Note - this
-macro can now be called for uninitialized data items as well as
-initialized data and functions.
@end table
+@deftypefn {Target Hook} void TARGET_ASM_SELECT_SECTION (tree @var{exp}, int @var{reloc}, unsigned HOST_WIDE_INT @var{align})
+Switches to the appropriate section for output of @var{exp}. You can
+assume that @var{exp} is either a @code{VAR_DECL} node or a constant of
+some sort. @var{reloc} indicates whether the initial value of @var{exp}
+requires link-time relocations. Bit 0 is set when variable contains
+local relocations only, while bit 1 is set for global relocations.
+Select the section by calling @code{data_section} or one of the
+alternatives for other sections. @var{align} is the constant alignment
+in bits.
+
+The default version of this function takes care of putting read-only
+variables in @code{readonly_data_section}.
+@end deftypefn
+
+@deftypefn {Target Hook} void TARGET_ASM_UNIQUE_SECTION (tree @var{decl}, int @var{reloc})
+Build up a unique section name, expressed as a @code{STRING_CST} node,
+and assign it to @samp{DECL_SECTION_NAME (@var{decl})}.
+As with @code{TARGET_ASM_SELECT_SECTION}, @var{reloc} indicates whether
+the initial value of @var{exp} requires link-time relocations.
+
+The default version of this function appends the symbol name to the
+ELF section name that would normally be used for the symbol. For
+example, the function @code{foo} would be placed in @code{.text.foo}.
+Whatever the actual target object format, this is often good enough.
+@end deftypefn
+
+@deftypefn {Target Hook} void TARGET_ASM_SELECT_RTX_SECTION (enum machine_mode @var{mode}, rtx @var{x}, unsigned HOST_WIDE_INT @var{align})
+Switches to the appropriate section for output of constant pool entry
+@var{x} in @var{mode}. You can assume that @var{x} is some kind of
+constant in RTL@. The argument @var{mode} is redundant except in the
+case of a @code{const_int} rtx. Select the section by calling
+@code{readonly_data_section} or one of the alternatives for other
+sections. @var{align} is the constant alignment in bits.
+
+The default version of this function takes care of putting symbolic
+constants in @code{flag_pic} mode in @code{data_section} and everything
+else in @code{readonly_data_section}.
+@end deftypefn
+
@node PIC
@section Position Independent Code
@cindex position independent code
should have attributes as specified by @var{flags}, which is a bit mask
of the @code{SECTION_*} flags defined in @file{output.h}. If @var{align}
is nonzero, it contains an alignment in bytes to be used for the section,
-otherwise some target default should be used. Only targets that must
+otherwise some target default should be used. Only targets that must
specify an alignment within the section directive need pay attention to
@var{align} -- we will still use @code{ASM_OUTPUT_ALIGN}.
@end deftypefn
@findex REAL_VALUE_TO_TARGET_DOUBLE
@findex REAL_VALUE_TO_TARGET_LONG_DOUBLE
These translate @var{x}, of type @code{REAL_VALUE_TYPE}, to the target's
-floating point representation, and store its bit pattern in the array of
-@code{long int} whose address is @var{l}. The number of elements in the
-output array is determined by the size of the desired target floating
-point data type: 32 bits of it go in each @code{long int} array
-element. Each array element holds 32 bits of the result, even if
-@code{long int} is wider than 32 bits on the host machine.
+floating point representation, and store its bit pattern in the variable
+@var{l}. For @code{REAL_VALUE_TO_TARGET_SINGLE}, this variable should
+be a simple @code{long int}. For the others, it should be an array of
+@code{long int}. The number of elements in this array is determined by
+the size of the desired target floating point data type: 32 bits of it
+go in each @code{long int} array element. Each array element holds 32
+bits of the result, even if @code{long int} is wider than 32 bits on the
+host machine.
The array element values are designed so that you can print them out
using @code{fprintf} in the order they should appear in the target
for making that name global, and a newline.
@findex ASM_WEAKEN_LABEL
-@item ASM_WEAKEN_LABEL
+@item ASM_WEAKEN_LABEL (@var{stream}, @var{name})
A C statement (sans semicolon) to output to the stdio stream
@var{stream} some commands that will make the label @var{name} weak;
that is, available for reference from other files but only used if
itself; before and after that, output the additional assembler syntax
for making that name weak, and a newline.
-If you don't define this macro, GCC will not support weak
-symbols and you should not define the @code{SUPPORTS_WEAK} macro.
+If you don't define this macro or @code{ASM_WEAKEN_DECL}, GCC will not
+support weak symbols and you should not define the @code{SUPPORTS_WEAK}
+macro.
+
+@findex ASM_WEAKEN_DECL
+@item ASM_WEAKEN_DECL (@var{stream}, @var{decl}, @var{name}, @var{value})
+Combines (and replaces) the function of @code{ASM_WEAKEN_LABEL} and
+@code{ASM_OUTPUT_WEAK_ALIAS}, allowing access to the associated function
+or variable decl. If @var{value} is not @code{NULL}, this C statement
+should output to the stdio stream @var{stream} assembler code which
+defines (equates) the weak symbol @var{name} to have the value
+@var{value}. If @var{value} is @code{NULL}, it should output commands
+to make @var{name} weak.
@findex SUPPORTS_WEAK
@item SUPPORTS_WEAK
A C expression which evaluates to true if the target supports weak symbols.
If you don't define this macro, @file{defaults.h} provides a default
-definition. If @code{ASM_WEAKEN_LABEL} is defined, the default
-definition is @samp{1}; otherwise, it is @samp{0}. Define this macro if
-you want to control weak symbol support with a compiler flag such as
-@option{-melf}.
+definition. If either @code{ASM_WEAKEN_LABEL} or @code{ASM_WEAKEN_DECL}
+is defined, the default definition is @samp{1}; otherwise, it is
+@samp{0}. Define this macro if you want to control weak symbol support
+with a compiler flag such as @option{-melf}.
@findex MAKE_DECL_ONE_ONLY (@var{decl})
@item MAKE_DECL_ONE_ONLY
This method will be chosen as the default by @file{target-def.h} if
@code{TARGET_ASM_NAMED_SECTION} is defined. A target that does not
-support arbitrary sections, but does support special designated
+support arbitrary sections, but does support special designated
constructor and destructor sections may define @code{CTORS_SECTION_ASM_OP}
and @code{DTORS_SECTION_ASM_OP} to achieve the same effect.
function called @code{_GLOBAL__DI} will be generated.
This function and the following one are used by collect2 when linking a
-shared library that needs constructors or destructors, or has DWARF2
+shared library that needs constructors or destructors, or has DWARF2
exception tables embedded in the code.
@item COLLECT_SHARED_FINI_FUNC (@var{stream}, @var{func})
If this macro is defined, you may use constructs of the form
@smallexample
-@samp{@{option0|option1|option2@dots{}@}}
+@samp{@{option0|option1|option2@dots{}@}}
@end smallexample
@noindent
in the output templates of patterns (@pxref{Output Template}) or in the
@code{OVERRIDE_OPTIONS}.
@end table
-@node Cross-compilation
+@node Floating Point
@section Cross Compilation and Floating Point
@cindex cross compilation and floating point
@cindex floating point and cross compilation
-While all modern machines use 2's complement representation for integers,
+While all modern machines use twos-complement representation for integers,
there are a variety of representations for floating point numbers. This
means that in a cross-compiler the representation of floating point numbers
in the compiled program may be different from that used in the machine
doing the compilation.
-@findex atof
Because different representation systems may offer different amounts of
-range and precision, the cross compiler cannot safely use the host
-machine's floating point arithmetic. Therefore, floating point constants
-must be represented in the target machine's format. This means that the
-cross compiler cannot use @code{atof} to parse a floating point constant;
-it must have its own special routine to use instead. Also, constant
-folding must emulate the target machine's arithmetic (or must not be done
-at all).
+range and precision, all floating point constants must be represented in
+the target machine's format. Therefore, the cross compiler cannot
+safely use the host machine's floating point arithmetic; it must emulate
+the target's arithmetic. To ensure consistency, GCC always uses
+emulation to work with floating point values, even when the host and
+target floating point formats are identical.
+
+The following macros are provided by @file{real.h} for the compiler to
+use. All parts of the compiler which generate or optimize
+floating-point calculations must use these macros. They may evaluate
+their operands more than once, so operands must not have side effects.
+
+@defmac REAL_VALUE_TYPE
+The C data type to be used to hold a floating point value in the target
+machine's format. Typically this is a @code{struct} containing an
+array of @code{HOST_WIDE_INT}, but all code should treat it as an opaque
+quantity.
+@end defmac
+
+@deftypefn Macro int REAL_VALUES_EQUAL (REAL_VALUE_TYPE @var{x}, REAL_VALUE_TYPE @var{y})
+Compares for equality the two values, @var{x} and @var{y}. If the target
+floating point format supports negative zeroes and/or NaNs,
+@samp{REAL_VALUES_EQUAL (-0.0, 0.0)} is true, and
+@samp{REAL_VALUES_EQUAL (NaN, NaN)} is false.
+@end deftypefn
-The macros in the following table should be defined only if you are cross
-compiling between different floating point formats.
+@deftypefn Macro int REAL_VALUES_LESS (REAL_VALUE_TYPE @var{x}, REAL_VALUE_TYPE @var{y})
+Tests whether @var{x} is less than @var{y}.
+@end deftypefn
-Otherwise, don't define them. Then default definitions will be set up which
-use @code{double} as the data type, @code{==} to test for equality, etc.
+@findex ldexp
+@deftypefn Macro REAL_VALUE_TYPE REAL_VALUE_LDEXP (REAL_VALUE_TYPE @var{x}, int @var{scale})
+Multiplies @var{x} by 2 raised to the power @var{scale}.
+@end deftypefn
-You don't need to worry about how many times you use an operand of any
-of these macros. The compiler never uses operands which have side effects.
+@deftypefn Macro HOST_WIDE_INT REAL_VALUE_FIX (REAL_VALUE_TYPE @var{x})
+Truncates @var{x} to a signed integer, rounding toward zero.
+@end deftypefn
-@table @code
-@findex REAL_VALUE_TYPE
-@item REAL_VALUE_TYPE
-A macro for the C data type to be used to hold a floating point value
-in the target machine's format. Typically this would be a
-@code{struct} containing an array of @code{int}.
-
-@findex REAL_VALUES_EQUAL
-@item REAL_VALUES_EQUAL (@var{x}, @var{y})
-A macro for a C expression which compares for equality the two values,
-@var{x} and @var{y}, both of type @code{REAL_VALUE_TYPE}.
-
-@findex REAL_VALUES_LESS
-@item REAL_VALUES_LESS (@var{x}, @var{y})
-A macro for a C expression which tests whether @var{x} is less than
-@var{y}, both values being of type @code{REAL_VALUE_TYPE} and
-interpreted as floating point numbers in the target machine's
-representation.
-
-@findex REAL_VALUE_LDEXP
-@findex ldexp
-@item REAL_VALUE_LDEXP (@var{x}, @var{scale})
-A macro for a C expression which performs the standard library
-function @code{ldexp}, but using the target machine's floating point
-representation. Both @var{x} and the value of the expression have
-type @code{REAL_VALUE_TYPE}. The second argument, @var{scale}, is an
-integer.
-
-@findex REAL_VALUE_FIX
-@item REAL_VALUE_FIX (@var{x})
-A macro whose definition is a C expression to convert the target-machine
-floating point value @var{x} to a signed integer. @var{x} has type
-@code{REAL_VALUE_TYPE}.
-
-@findex REAL_VALUE_UNSIGNED_FIX
-@item REAL_VALUE_UNSIGNED_FIX (@var{x})
-A macro whose definition is a C expression to convert the target-machine
-floating point value @var{x} to an unsigned integer. @var{x} has type
-@code{REAL_VALUE_TYPE}.
-
-@findex REAL_VALUE_RNDZINT
-@item REAL_VALUE_RNDZINT (@var{x})
-A macro whose definition is a C expression to round the target-machine
-floating point value @var{x} towards zero to an integer value (but still
-as a floating point number). @var{x} has type @code{REAL_VALUE_TYPE},
-and so does the value.
-
-@findex REAL_VALUE_UNSIGNED_RNDZINT
-@item REAL_VALUE_UNSIGNED_RNDZINT (@var{x})
-A macro whose definition is a C expression to round the target-machine
-floating point value @var{x} towards zero to an unsigned integer value
-(but still represented as a floating point number). @var{x} has type
-@code{REAL_VALUE_TYPE}, and so does the value.
-
-@findex REAL_VALUE_ATOF
-@item REAL_VALUE_ATOF (@var{string}, @var{mode})
-A macro for a C expression which converts @var{string}, an expression of
-type @code{char *}, into a floating point number in the target machine's
-representation for mode @var{mode}. The value has type
-@code{REAL_VALUE_TYPE}.
-
-@findex REAL_INFINITY
-@item REAL_INFINITY
-Define this macro if infinity is a possible floating point value, and
-therefore division by 0 is legitimate.
-
-@findex REAL_VALUE_ISINF
-@findex isinf
-@item REAL_VALUE_ISINF (@var{x})
-A macro for a C expression which determines whether @var{x}, a floating
-point value, is infinity. The value has type @code{int}.
-By default, this is defined to call @code{isinf}.
-
-@findex REAL_VALUE_ISNAN
-@findex isnan
-@item REAL_VALUE_ISNAN (@var{x})
-A macro for a C expression which determines whether @var{x}, a floating
-point value, is a ``nan'' (not-a-number). The value has type
-@code{int}. By default, this is defined to call @code{isnan}.
-@end table
+@deftypefn Macro {unsigned HOST_WIDE_INT} REAL_VALUE_UNSIGNED_FIX (REAL_VALUE_TYPE @var{x})
+Truncates @var{x} to an unsigned integer, rounding toward zero. If
+@var{x} is negative, returns zero.
+@end deftypefn
-@cindex constant folding and floating point
-Define the following additional macros if you want to make floating
-point constant folding work while cross compiling. If you don't
-define them, cross compilation is still possible, but constant folding
-will not happen for floating point values.
+@deftypefn Macro REAL_VALUE_TYPE REAL_VALUE_RNDZINT (REAL_VALUE_TYPE @var{x})
+Rounds the target-machine floating point value @var{x} towards zero to an
+integer value, but leaves it represented as a floating point number.
+@end deftypefn
-@table @code
-@findex REAL_ARITHMETIC
-@item REAL_ARITHMETIC (@var{output}, @var{code}, @var{x}, @var{y})
-A macro for a C statement which calculates an arithmetic operation of
-the two floating point values @var{x} and @var{y}, both of type
-@code{REAL_VALUE_TYPE} in the target machine's representation, to
-produce a result of the same type and representation which is stored
-in @var{output} (which will be a variable).
-
-The operation to be performed is specified by @var{code}, a tree code
-which will always be one of the following: @code{PLUS_EXPR},
-@code{MINUS_EXPR}, @code{MULT_EXPR}, @code{RDIV_EXPR},
-@code{MAX_EXPR}, @code{MIN_EXPR}.
-
-@cindex overflow while constant folding
-The expansion of this macro is responsible for checking for overflow.
-If overflow happens, the macro expansion should execute the statement
-@code{return 0;}, which indicates the inability to perform the
-arithmetic operation requested.
-
-@findex REAL_VALUE_NEGATE
-@item REAL_VALUE_NEGATE (@var{x})
-A macro for a C expression which returns the negative of the floating
-point value @var{x}. Both @var{x} and the value of the expression
-have type @code{REAL_VALUE_TYPE} and are in the target machine's
-floating point representation.
-
-There is no way for this macro to report overflow, since overflow
-can't happen in the negation operation.
-
-@findex REAL_VALUE_TRUNCATE
-@item REAL_VALUE_TRUNCATE (@var{mode}, @var{x})
-A macro for a C expression which converts the floating point value
-@var{x} to mode @var{mode}.
-
-Both @var{x} and the value of the expression are in the target machine's
-floating point representation and have type @code{REAL_VALUE_TYPE}.
-However, the value should have an appropriate bit pattern to be output
-properly as a floating constant whose precision accords with mode
-@var{mode}.
+@deftypefn Macro REAL_VALUE_TYPE REAL_VALUE_UNSIGNED_RNDZINT (REAL_VALUE_TYPE @var{x})
+Rounds the target-machine floating point value @var{x} towards zero to an
+unsigned integer value, but leaves it represented as a floating point
+number. If @var{x} is negative, returns (positive) zero.
+@end deftypefn
-There is no way for this macro to report overflow.
+@deftypefn Macro REAL_VALUE_TYPE REAL_VALUE_ATOF (const char *@var{string}, enum machine_mode @var{mode})
+Converts @var{string} into a floating point number in the target machine's
+representation for mode @var{mode}. This routine can handle both
+decimal and hexadecimal floating point constants, using the syntax
+defined by the C language for both.
+@end deftypefn
+
+@deftypefn Macro int REAL_VALUE_NEGATIVE (REAL_VALUE_TYPE @var{x})
+Returns 1 if @var{x} is negative (including negative zero), 0 otherwise.
+@end deftypefn
+
+@deftypefn Macro int REAL_VALUE_ISINF (REAL_VALUE_TYPE @var{x})
+Determines whether @var{x} represents infinity (positive or negative).
+@end deftypefn
+
+@deftypefn Macro int REAL_VALUE_ISNAN (REAL_VALUE_TYPE @var{x})
+Determines whether @var{x} represents a ``NaN'' (not-a-number).
+@end deftypefn
-@findex REAL_VALUE_TO_INT
-@item REAL_VALUE_TO_INT (@var{low}, @var{high}, @var{x})
-A macro for a C expression which converts a floating point value
-@var{x} into a double-precision integer which is then stored into
-@var{low} and @var{high}, two variables of type @var{int}.
+@deftypefn Macro void REAL_ARITHMETIC (REAL_VALUE_TYPE @var{output}, enum tree_code @var{code}, REAL_VALUE_TYPE @var{x}, REAL_VALUE_TYPE @var{y})
+Calculates an arithmetic operation on the two floating point values
+@var{x} and @var{y}, storing the result in @var{output} (which must be a
+variable).
-@item REAL_VALUE_FROM_INT (@var{x}, @var{low}, @var{high}, @var{mode})
+The operation to be performed is specified by @var{code}. Only the
+following codes are supported: @code{PLUS_EXPR}, @code{MINUS_EXPR},
+@code{MULT_EXPR}, @code{RDIV_EXPR}, @code{MAX_EXPR}, @code{MIN_EXPR}.
+
+If @code{REAL_ARITHMETIC} is asked to evaluate division by zero and the
+target's floating point format cannot represent infinity, it will call
+@code{abort}. Callers should check for this situation first, using
+@code{MODE_HAS_INFINITIES}. @xref{Storage Layout}.
+@end deftypefn
+
+@deftypefn Macro REAL_VALUE_TYPE REAL_VALUE_NEGATE (REAL_VALUE_TYPE @var{x})
+Returns the negative of the floating point value @var{x}.
+@end deftypefn
+
+@deftypefn Macro REAL_VALUE_TYPE REAL_VALUE_ABS (REAL_VALUE_TYPE @var{x})
+Returns the absolute value of @var{x}.
+@end deftypefn
+
+@deftypefn Macro REAL_VALUE_TYPE REAL_VALUE_TRUNCATE (REAL_VALUE_TYPE @var{mode}, enum machine_mode @var{x})
+Truncates the floating point value @var{x} to fit in @var{mode}. The
+return value is still a full-size @code{REAL_VALUE_TYPE}, but it has an
+appropriate bit pattern to be output asa floating constant whose
+precision accords with mode @var{mode}.
+@end deftypefn
+
+@deftypefn Macro void REAL_VALUE_TO_INT (HOST_WIDE_INT @var{low}, HOST_WIDE_INT @var{high}, REAL_VALUE_TYPE @var{x})
+Converts a floating point value @var{x} into a double-precision integer
+which is then stored into @var{low} and @var{high}. If the value is not
+integral, it is truncated.
+@end deftypefn
+
+@deftypefn Macro void REAL_VALUE_FROM_INT (REAL_VALUE_TYPE @var{x}, HOST_WIDE_INT @var{low}, HOST_WIDE_INT @var{high}, enum machine_mode @var{mode})
@findex REAL_VALUE_FROM_INT
-A macro for a C expression which converts a double-precision integer
-found in @var{low} and @var{high}, two variables of type @var{int},
-into a floating point value which is then stored into @var{x}.
-The value is in the target machine's representation for mode @var{mode}
-and has the type @code{REAL_VALUE_TYPE}.
-@end table
+Converts a double-precision integer found in @var{low} and @var{high},
+into a floating point value which is then stored into @var{x}. The
+value is truncated to fit in mode @var{mode}.
+@end deftypefn
@node Mode Switching
@section Mode Switching Instructions
target specific attribute attached to it, it will not be inlined.
@end deftypefn
+@node MIPS Coprocessors
+@section Defining coprocessor specifics for MIPS targets.
+@cindex MIPS coprocessor-definition macros
+
+The MIPS specification allows MIPS implementations to have as many as 4
+coprocessors, each with as many as 32 private registers. gcc supports
+accessing these registers and transferring values between the registers
+and memory using asm-ized variables. For example:
+
+@smallexample
+ register unsigned int cp0count asm ("c0r1");
+ unsigned int d;
+
+ d = cp0count + 3;
+@end smallexample
+
+(``c0r1'' is the default name of register 1 in coprocessor 0; alternate
+names may be added as described below, or the default names may be
+overridden entirely in @code{SUBTARGET_CONDITIONAL_REGISTER_USAGE}.)
+
+Coprocessor registers are assumed to be epilogue-used; sets to them will
+be preserved even if it does not appear that the register is used again
+later in the function.
+
+Another note: according to the MIPS spec, coprocessor 1 (if present) is
+the FPU. One accesses COP1 registers through standard mips
+floating-point support; they are not included in this mechanism.
+
+There is one macro used in defining the MIPS coprocessor interface which
+you may want to override in subtargets; it is described below.
+
+@table @code
+
+@item ALL_COP_ADDITIONAL_REGISTER_NAMES
+@findex ALL_COP_ADDITIONAL_REGISTER_NAMES
+A comma-separated list (with leading comma) of pairs describing the
+alternate names of coprocessor registers. The format of each entry should be
+@smallexample
+@{ @var{alternatename}, @var{register_number}@}
+@end smallexample
+Default: empty.
+
+@end table
+
@node Misc
@section Miscellaneous Parameters
@cindex parameters, miscellaneous
lists.
@end table
+
+@deftypefn {Target Hook} bool TARGET_CANNOT_MODIFY_JUMPS_P (void)
+This target hook returns @code{true} past the point in which new jump
+instructions could be created. On machines that require a register for
+every jump such as the SHmedia ISA of SH5, this point would typically be
+reload, so this target hook should be defined to a function such as:
+
+@smallexample
+static bool
+cannot_modify_jumps_past_reload_p ()
+@{
+ return (reload_completed || reload_in_progress);
+@}
+@end smallexample
+@end deftypefn
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