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diff --git a/binutils-2.25/gas/doc/c-hppa.texi b/binutils-2.25/gas/doc/c-hppa.texi new file mode 100644 index 00000000..2bb1ae4f --- /dev/null +++ b/binutils-2.25/gas/doc/c-hppa.texi @@ -0,0 +1,301 @@ +@c Copyright 1991, 1992, 1993, 1994, 1995, 1998, 2004, 2011 +@c Free Software Foundation, Inc. +@c This is part of the GAS manual. +@c For copying conditions, see the file as.texinfo. +@page +@node HPPA-Dependent +@chapter HPPA Dependent Features + +@cindex support +@menu +* HPPA Notes:: Notes +* HPPA Options:: Options +* HPPA Syntax:: Syntax +* HPPA Floating Point:: Floating Point +* HPPA Directives:: HPPA Machine Directives +* HPPA Opcodes:: Opcodes +@end menu + +@node HPPA Notes +@section Notes +As a back end for @sc{gnu} @sc{cc} @code{@value{AS}} has been throughly tested and should +work extremely well. We have tested it only minimally on hand written assembly +code and no one has tested it much on the assembly output from the HP +compilers. + +The format of the debugging sections has changed since the original +@code{@value{AS}} port (version 1.3X) was released; therefore, +you must rebuild all HPPA objects and libraries with the new +assembler so that you can debug the final executable. + +The HPPA @code{@value{AS}} port generates a small subset of the relocations +available in the SOM and ELF object file formats. Additional relocation +support will be added as it becomes necessary. + +@node HPPA Options +@section Options +@code{@value{AS}} has no machine-dependent command-line options for the HPPA. + +@cindex HPPA Syntax +@node HPPA Syntax +@section Syntax +The assembler syntax closely follows the HPPA instruction set +reference manual; assembler directives and general syntax closely follow the +HPPA assembly language reference manual, with a few noteworthy differences. + +First, a colon may immediately follow a label definition. This is +simply for compatibility with how most assembly language programmers +write code. + +Some obscure expression parsing problems may affect hand written code which +uses the @code{spop} instructions, or code which makes significant +use of the @code{!} line separator. + +@code{@value{AS}} is much less forgiving about missing arguments and other +similar oversights than the HP assembler. @code{@value{AS}} notifies you +of missing arguments as syntax errors; this is regarded as a feature, not a +bug. + +Finally, @code{@value{AS}} allows you to use an external symbol without +explicitly importing the symbol. @emph{Warning:} in the future this will be +an error for HPPA targets. + +Special characters for HPPA targets include: + +@samp{;} is the line comment character. + +@samp{!} can be used instead of a newline to separate statements. + +Since @samp{$} has no special meaning, you may use it in symbol names. + +@node HPPA Floating Point +@section Floating Point +@cindex floating point, HPPA (@sc{ieee}) +@cindex HPPA floating point (@sc{ieee}) +The HPPA family uses @sc{ieee} floating-point numbers. + +@node HPPA Directives +@section HPPA Assembler Directives + +@code{@value{AS}} for the HPPA supports many additional directives for +compatibility with the native assembler. This section describes them only +briefly. For detailed information on HPPA-specific assembler directives, see +@cite{HP9000 Series 800 Assembly Language Reference Manual} (HP 92432-90001). + +@cindex HPPA directives not supported +@code{@value{AS}} does @emph{not} support the following assembler directives +described in the HP manual: + +@example +.endm .liston +.enter .locct +.leave .macro +.listoff +@end example + +@cindex @code{.param} on HPPA +Beyond those implemented for compatibility, @code{@value{AS}} supports one +additional assembler directive for the HPPA: @code{.param}. It conveys +register argument locations for static functions. Its syntax closely follows +the @code{.export} directive. + +@cindex HPPA-only directives +These are the additional directives in @code{@value{AS}} for the HPPA: + +@table @code +@item .block @var{n} +@itemx .blockz @var{n} +Reserve @var{n} bytes of storage, and initialize them to zero. + +@item .call +Mark the beginning of a procedure call. Only the special case with @emph{no +arguments} is allowed. + +@item .callinfo [ @var{param}=@var{value}, @dots{} ] [ @var{flag}, @dots{} ] +Specify a number of parameters and flags that define the environment for a +procedure. + +@var{param} may be any of @samp{frame} (frame size), @samp{entry_gr} (end of +general register range), @samp{entry_fr} (end of float register range), +@samp{entry_sr} (end of space register range). + +The values for @var{flag} are @samp{calls} or @samp{caller} (proc has +subroutines), @samp{no_calls} (proc does not call subroutines), @samp{save_rp} +(preserve return pointer), @samp{save_sp} (proc preserves stack pointer), +@samp{no_unwind} (do not unwind this proc), @samp{hpux_int} (proc is interrupt +routine). + +@item .code +Assemble into the standard section called @samp{$TEXT$}, subsection +@samp{$CODE$}. + +@ifset SOM +@item .copyright "@var{string}" +In the SOM object format, insert @var{string} into the object code, marked as a +copyright string. +@end ifset + +@ifset ELF +@item .copyright "@var{string}" +In the ELF object format, insert @var{string} into the object code, marked as a +version string. +@end ifset + +@item .enter +Not yet supported; the assembler rejects programs containing this directive. + +@item .entry +Mark the beginning of a procedure. + +@item .exit +Mark the end of a procedure. + +@item .export @var{name} [ ,@var{typ} ] [ ,@var{param}=@var{r} ] +Make a procedure @var{name} available to callers. @var{typ}, if present, must +be one of @samp{absolute}, @samp{code} (ELF only, not SOM), @samp{data}, +@samp{entry}, @samp{data}, @samp{entry}, @samp{millicode}, @samp{plabel}, +@samp{pri_prog}, or @samp{sec_prog}. + +@var{param}, if present, provides either relocation information for the +procedure arguments and result, or a privilege level. @var{param} may be +@samp{argw@var{n}} (where @var{n} ranges from @code{0} to @code{3}, and +indicates one of four one-word arguments); @samp{rtnval} (the procedure's +result); or @samp{priv_lev} (privilege level). For arguments or the result, +@var{r} specifies how to relocate, and must be one of @samp{no} (not +relocatable), @samp{gr} (argument is in general register), @samp{fr} (in +floating point register), or @samp{fu} (upper half of float register). +For @samp{priv_lev}, @var{r} is an integer. + +@item .half @var{n} +Define a two-byte integer constant @var{n}; synonym for the portable +@code{@value{AS}} directive @code{.short}. + +@item .import @var{name} [ ,@var{typ} ] +Converse of @code{.export}; make a procedure available to call. The arguments +use the same conventions as the first two arguments for @code{.export}. + +@item .label @var{name} +Define @var{name} as a label for the current assembly location. + +@item .leave +Not yet supported; the assembler rejects programs containing this directive. + +@item .origin @var{lc} +Advance location counter to @var{lc}. Synonym for the @code{@value{AS}} +portable directive @code{.org}. + +@item .param @var{name} [ ,@var{typ} ] [ ,@var{param}=@var{r} ] +@c Not in HP manual; @sc{gnu} HPPA extension +Similar to @code{.export}, but used for static procedures. + +@item .proc +Use preceding the first statement of a procedure. + +@item .procend +Use following the last statement of a procedure. + +@item @var{label} .reg @var{expr} +@c ?? Not in HP manual (Jan 1988 vn) +Synonym for @code{.equ}; define @var{label} with the absolute expression +@var{expr} as its value. + +@item .space @var{secname} [ ,@var{params} ] +Switch to section @var{secname}, creating a new section by that name if +necessary. You may only use @var{params} when creating a new section, not +when switching to an existing one. @var{secname} may identify a section by +number rather than by name. + +If specified, the list @var{params} declares attributes of the section, +identified by keywords. The keywords recognized are @samp{spnum=@var{exp}} +(identify this section by the number @var{exp}, an absolute expression), +@samp{sort=@var{exp}} (order sections according to this sort key when linking; +@var{exp} is an absolute expression), @samp{unloadable} (section contains no +loadable data), @samp{notdefined} (this section defined elsewhere), and +@samp{private} (data in this section not available to other programs). + +@item .spnum @var{secnam} +@c ?? Not in HP manual (Jan 1988) +Allocate four bytes of storage, and initialize them with the section number of +the section named @var{secnam}. (You can define the section number with the +HPPA @code{.space} directive.) + +@cindex @code{string} directive on HPPA +@item .string "@var{str}" +Copy the characters in the string @var{str} to the object file. +@xref{Strings,,Strings}, for information on escape sequences you can use in +@code{@value{AS}} strings. + +@emph{Warning!} The HPPA version of @code{.string} differs from the +usual @code{@value{AS}} definition: it does @emph{not} write a zero byte +after copying @var{str}. + +@item .stringz "@var{str}" +Like @code{.string}, but appends a zero byte after copying @var{str} to object +file. + +@item .subspa @var{name} [ ,@var{params} ] +@itemx .nsubspa @var{name} [ ,@var{params} ] +Similar to @code{.space}, but selects a subsection @var{name} within the +current section. You may only specify @var{params} when you create a +subsection (in the first instance of @code{.subspa} for this @var{name}). + +If specified, the list @var{params} declares attributes of the subsection, +identified by keywords. The keywords recognized are @samp{quad=@var{expr}} +(``quadrant'' for this subsection), @samp{align=@var{expr}} (alignment for +beginning of this subsection; a power of two), @samp{access=@var{expr}} (value +for ``access rights'' field), @samp{sort=@var{expr}} (sorting order for this +subspace in link), @samp{code_only} (subsection contains only code), +@samp{unloadable} (subsection cannot be loaded into memory), @samp{comdat} +(subsection is comdat), @samp{common} (subsection is common block), +@samp{dup_comm} (subsection may have duplicate names), or @samp{zero} +(subsection is all zeros, do not write in object file). + +@code{.nsubspa} always creates a new subspace with the given name, even +if one with the same name already exists. + +@samp{comdat}, @samp{common} and @samp{dup_comm} can be used to implement +various flavors of one-only support when using the SOM linker. The SOM +linker only supports specific combinations of these flags. The details +are not documented. A brief description is provided here. + +@samp{comdat} provides a form of linkonce support. It is useful for +both code and data subspaces. A @samp{comdat} subspace has a key symbol +marked by the @samp{is_comdat} flag or @samp{ST_COMDAT}. Only the first +subspace for any given key is selected. The key symbol becomes universal +in shared links. This is similar to the behavior of @samp{secondary_def} +symbols. + +@samp{common} provides Fortran named common support. It is only useful +for data subspaces. Symbols with the flag @samp{is_common} retain this +flag in shared links. Referencing a @samp{is_common} symbol in a shared +library from outside the library doesn't work. Thus, @samp{is_common} +symbols must be output whenever they are needed. + +@samp{common} and @samp{dup_comm} together provide Cobol common support. +The subspaces in this case must all be the same length. Otherwise, this +support is similar to the Fortran common support. + +@samp{dup_comm} by itself provides a type of one-only support for code. +Only the first @samp{dup_comm} subspace is selected. There is a rather +complex algorithm to compare subspaces. Code symbols marked with the +@samp{dup_common} flag are hidden. This support was intended for "C++ +duplicate inlines". + +A simplified technique is used to mark the flags of symbols based on +the flags of their subspace. A symbol with the scope SS_UNIVERSAL and +type ST_ENTRY, ST_CODE or ST_DATA is marked with the corresponding +settings of @samp{comdat}, @samp{common} and @samp{dup_comm} from the +subspace, respectively. This avoids having to introduce additional +directives to mark these symbols. The HP assembler sets @samp{is_common} +from @samp{common}. However, it doesn't set the @samp{dup_common} from +@samp{dup_comm}. It doesn't have @samp{comdat} support. + +@item .version "@var{str}" +Write @var{str} as version identifier in object code. +@end table + +@node HPPA Opcodes +@section Opcodes +For detailed information on the HPPA machine instruction set, see +@cite{PA-RISC Architecture and Instruction Set Reference Manual} +(HP 09740-90039). |