1 |
179 |
jshamlet |
@c Copyright 1991, 1992, 1993, 1994, 1995, 1998, 2004, 2011
|
2 |
|
|
@c Free Software Foundation, Inc.
|
3 |
|
|
@c This is part of the GAS manual.
|
4 |
|
|
@c For copying conditions, see the file as.texinfo.
|
5 |
|
|
@page
|
6 |
|
|
@node HPPA-Dependent
|
7 |
|
|
@chapter HPPA Dependent Features
|
8 |
|
|
|
9 |
|
|
@cindex support
|
10 |
|
|
@menu
|
11 |
|
|
* HPPA Notes:: Notes
|
12 |
|
|
* HPPA Options:: Options
|
13 |
|
|
* HPPA Syntax:: Syntax
|
14 |
|
|
* HPPA Floating Point:: Floating Point
|
15 |
|
|
* HPPA Directives:: HPPA Machine Directives
|
16 |
|
|
* HPPA Opcodes:: Opcodes
|
17 |
|
|
@end menu
|
18 |
|
|
|
19 |
|
|
@node HPPA Notes
|
20 |
|
|
@section Notes
|
21 |
|
|
As a back end for @sc{gnu} @sc{cc} @code{@value{AS}} has been throughly tested and should
|
22 |
|
|
work extremely well. We have tested it only minimally on hand written assembly
|
23 |
|
|
code and no one has tested it much on the assembly output from the HP
|
24 |
|
|
compilers.
|
25 |
|
|
|
26 |
|
|
The format of the debugging sections has changed since the original
|
27 |
|
|
@code{@value{AS}} port (version 1.3X) was released; therefore,
|
28 |
|
|
you must rebuild all HPPA objects and libraries with the new
|
29 |
|
|
assembler so that you can debug the final executable.
|
30 |
|
|
|
31 |
|
|
The HPPA @code{@value{AS}} port generates a small subset of the relocations
|
32 |
|
|
available in the SOM and ELF object file formats. Additional relocation
|
33 |
|
|
support will be added as it becomes necessary.
|
34 |
|
|
|
35 |
|
|
@node HPPA Options
|
36 |
|
|
@section Options
|
37 |
|
|
@code{@value{AS}} has no machine-dependent command-line options for the HPPA.
|
38 |
|
|
|
39 |
|
|
@cindex HPPA Syntax
|
40 |
|
|
@node HPPA Syntax
|
41 |
|
|
@section Syntax
|
42 |
|
|
The assembler syntax closely follows the HPPA instruction set
|
43 |
|
|
reference manual; assembler directives and general syntax closely follow the
|
44 |
|
|
HPPA assembly language reference manual, with a few noteworthy differences.
|
45 |
|
|
|
46 |
|
|
First, a colon may immediately follow a label definition. This is
|
47 |
|
|
simply for compatibility with how most assembly language programmers
|
48 |
|
|
write code.
|
49 |
|
|
|
50 |
|
|
Some obscure expression parsing problems may affect hand written code which
|
51 |
|
|
uses the @code{spop} instructions, or code which makes significant
|
52 |
|
|
use of the @code{!} line separator.
|
53 |
|
|
|
54 |
|
|
@code{@value{AS}} is much less forgiving about missing arguments and other
|
55 |
|
|
similar oversights than the HP assembler. @code{@value{AS}} notifies you
|
56 |
|
|
of missing arguments as syntax errors; this is regarded as a feature, not a
|
57 |
|
|
bug.
|
58 |
|
|
|
59 |
|
|
Finally, @code{@value{AS}} allows you to use an external symbol without
|
60 |
|
|
explicitly importing the symbol. @emph{Warning:} in the future this will be
|
61 |
|
|
an error for HPPA targets.
|
62 |
|
|
|
63 |
|
|
Special characters for HPPA targets include:
|
64 |
|
|
|
65 |
|
|
@samp{;} is the line comment character.
|
66 |
|
|
|
67 |
|
|
@samp{!} can be used instead of a newline to separate statements.
|
68 |
|
|
|
69 |
|
|
Since @samp{$} has no special meaning, you may use it in symbol names.
|
70 |
|
|
|
71 |
|
|
@node HPPA Floating Point
|
72 |
|
|
@section Floating Point
|
73 |
|
|
@cindex floating point, HPPA (@sc{ieee})
|
74 |
|
|
@cindex HPPA floating point (@sc{ieee})
|
75 |
|
|
The HPPA family uses @sc{ieee} floating-point numbers.
|
76 |
|
|
|
77 |
|
|
@node HPPA Directives
|
78 |
|
|
@section HPPA Assembler Directives
|
79 |
|
|
|
80 |
|
|
@code{@value{AS}} for the HPPA supports many additional directives for
|
81 |
|
|
compatibility with the native assembler. This section describes them only
|
82 |
|
|
briefly. For detailed information on HPPA-specific assembler directives, see
|
83 |
|
|
@cite{HP9000 Series 800 Assembly Language Reference Manual} (HP 92432-90001).
|
84 |
|
|
|
85 |
|
|
@cindex HPPA directives not supported
|
86 |
|
|
@code{@value{AS}} does @emph{not} support the following assembler directives
|
87 |
|
|
described in the HP manual:
|
88 |
|
|
|
89 |
|
|
@example
|
90 |
|
|
.endm .liston
|
91 |
|
|
.enter .locct
|
92 |
|
|
.leave .macro
|
93 |
|
|
.listoff
|
94 |
|
|
@end example
|
95 |
|
|
|
96 |
|
|
@cindex @code{.param} on HPPA
|
97 |
|
|
Beyond those implemented for compatibility, @code{@value{AS}} supports one
|
98 |
|
|
additional assembler directive for the HPPA: @code{.param}. It conveys
|
99 |
|
|
register argument locations for static functions. Its syntax closely follows
|
100 |
|
|
the @code{.export} directive.
|
101 |
|
|
|
102 |
|
|
@cindex HPPA-only directives
|
103 |
|
|
These are the additional directives in @code{@value{AS}} for the HPPA:
|
104 |
|
|
|
105 |
|
|
@table @code
|
106 |
|
|
@item .block @var{n}
|
107 |
|
|
@itemx .blockz @var{n}
|
108 |
|
|
Reserve @var{n} bytes of storage, and initialize them to zero.
|
109 |
|
|
|
110 |
|
|
@item .call
|
111 |
|
|
Mark the beginning of a procedure call. Only the special case with @emph{no
|
112 |
|
|
arguments} is allowed.
|
113 |
|
|
|
114 |
|
|
@item .callinfo [ @var{param}=@var{value}, @dots{} ] [ @var{flag}, @dots{} ]
|
115 |
|
|
Specify a number of parameters and flags that define the environment for a
|
116 |
|
|
procedure.
|
117 |
|
|
|
118 |
|
|
@var{param} may be any of @samp{frame} (frame size), @samp{entry_gr} (end of
|
119 |
|
|
general register range), @samp{entry_fr} (end of float register range),
|
120 |
|
|
@samp{entry_sr} (end of space register range).
|
121 |
|
|
|
122 |
|
|
The values for @var{flag} are @samp{calls} or @samp{caller} (proc has
|
123 |
|
|
subroutines), @samp{no_calls} (proc does not call subroutines), @samp{save_rp}
|
124 |
|
|
(preserve return pointer), @samp{save_sp} (proc preserves stack pointer),
|
125 |
|
|
@samp{no_unwind} (do not unwind this proc), @samp{hpux_int} (proc is interrupt
|
126 |
|
|
routine).
|
127 |
|
|
|
128 |
|
|
@item .code
|
129 |
|
|
Assemble into the standard section called @samp{$TEXT$}, subsection
|
130 |
|
|
@samp{$CODE$}.
|
131 |
|
|
|
132 |
|
|
@ifset SOM
|
133 |
|
|
@item .copyright "@var{string}"
|
134 |
|
|
In the SOM object format, insert @var{string} into the object code, marked as a
|
135 |
|
|
copyright string.
|
136 |
|
|
@end ifset
|
137 |
|
|
|
138 |
|
|
@ifset ELF
|
139 |
|
|
@item .copyright "@var{string}"
|
140 |
|
|
In the ELF object format, insert @var{string} into the object code, marked as a
|
141 |
|
|
version string.
|
142 |
|
|
@end ifset
|
143 |
|
|
|
144 |
|
|
@item .enter
|
145 |
|
|
Not yet supported; the assembler rejects programs containing this directive.
|
146 |
|
|
|
147 |
|
|
@item .entry
|
148 |
|
|
Mark the beginning of a procedure.
|
149 |
|
|
|
150 |
|
|
@item .exit
|
151 |
|
|
Mark the end of a procedure.
|
152 |
|
|
|
153 |
|
|
@item .export @var{name} [ ,@var{typ} ] [ ,@var{param}=@var{r} ]
|
154 |
|
|
Make a procedure @var{name} available to callers. @var{typ}, if present, must
|
155 |
|
|
be one of @samp{absolute}, @samp{code} (ELF only, not SOM), @samp{data},
|
156 |
|
|
@samp{entry}, @samp{data}, @samp{entry}, @samp{millicode}, @samp{plabel},
|
157 |
|
|
@samp{pri_prog}, or @samp{sec_prog}.
|
158 |
|
|
|
159 |
|
|
@var{param}, if present, provides either relocation information for the
|
160 |
|
|
procedure arguments and result, or a privilege level. @var{param} may be
|
161 |
|
|
@samp{argw@var{n}} (where @var{n} ranges from @code{0} to @code{3}, and
|
162 |
|
|
indicates one of four one-word arguments); @samp{rtnval} (the procedure's
|
163 |
|
|
result); or @samp{priv_lev} (privilege level). For arguments or the result,
|
164 |
|
|
@var{r} specifies how to relocate, and must be one of @samp{no} (not
|
165 |
|
|
relocatable), @samp{gr} (argument is in general register), @samp{fr} (in
|
166 |
|
|
floating point register), or @samp{fu} (upper half of float register).
|
167 |
|
|
For @samp{priv_lev}, @var{r} is an integer.
|
168 |
|
|
|
169 |
|
|
@item .half @var{n}
|
170 |
|
|
Define a two-byte integer constant @var{n}; synonym for the portable
|
171 |
|
|
@code{@value{AS}} directive @code{.short}.
|
172 |
|
|
|
173 |
|
|
@item .import @var{name} [ ,@var{typ} ]
|
174 |
|
|
Converse of @code{.export}; make a procedure available to call. The arguments
|
175 |
|
|
use the same conventions as the first two arguments for @code{.export}.
|
176 |
|
|
|
177 |
|
|
@item .label @var{name}
|
178 |
|
|
Define @var{name} as a label for the current assembly location.
|
179 |
|
|
|
180 |
|
|
@item .leave
|
181 |
|
|
Not yet supported; the assembler rejects programs containing this directive.
|
182 |
|
|
|
183 |
|
|
@item .origin @var{lc}
|
184 |
|
|
Advance location counter to @var{lc}. Synonym for the @code{@value{AS}}
|
185 |
|
|
portable directive @code{.org}.
|
186 |
|
|
|
187 |
|
|
@item .param @var{name} [ ,@var{typ} ] [ ,@var{param}=@var{r} ]
|
188 |
|
|
@c Not in HP manual; @sc{gnu} HPPA extension
|
189 |
|
|
Similar to @code{.export}, but used for static procedures.
|
190 |
|
|
|
191 |
|
|
@item .proc
|
192 |
|
|
Use preceding the first statement of a procedure.
|
193 |
|
|
|
194 |
|
|
@item .procend
|
195 |
|
|
Use following the last statement of a procedure.
|
196 |
|
|
|
197 |
|
|
@item @var{label} .reg @var{expr}
|
198 |
|
|
@c ?? Not in HP manual (Jan 1988 vn)
|
199 |
|
|
Synonym for @code{.equ}; define @var{label} with the absolute expression
|
200 |
|
|
@var{expr} as its value.
|
201 |
|
|
|
202 |
|
|
@item .space @var{secname} [ ,@var{params} ]
|
203 |
|
|
Switch to section @var{secname}, creating a new section by that name if
|
204 |
|
|
necessary. You may only use @var{params} when creating a new section, not
|
205 |
|
|
when switching to an existing one. @var{secname} may identify a section by
|
206 |
|
|
number rather than by name.
|
207 |
|
|
|
208 |
|
|
If specified, the list @var{params} declares attributes of the section,
|
209 |
|
|
identified by keywords. The keywords recognized are @samp{spnum=@var{exp}}
|
210 |
|
|
(identify this section by the number @var{exp}, an absolute expression),
|
211 |
|
|
@samp{sort=@var{exp}} (order sections according to this sort key when linking;
|
212 |
|
|
@var{exp} is an absolute expression), @samp{unloadable} (section contains no
|
213 |
|
|
loadable data), @samp{notdefined} (this section defined elsewhere), and
|
214 |
|
|
@samp{private} (data in this section not available to other programs).
|
215 |
|
|
|
216 |
|
|
@item .spnum @var{secnam}
|
217 |
|
|
@c ?? Not in HP manual (Jan 1988)
|
218 |
|
|
Allocate four bytes of storage, and initialize them with the section number of
|
219 |
|
|
the section named @var{secnam}. (You can define the section number with the
|
220 |
|
|
HPPA @code{.space} directive.)
|
221 |
|
|
|
222 |
|
|
@cindex @code{string} directive on HPPA
|
223 |
|
|
@item .string "@var{str}"
|
224 |
|
|
Copy the characters in the string @var{str} to the object file.
|
225 |
|
|
@xref{Strings,,Strings}, for information on escape sequences you can use in
|
226 |
|
|
@code{@value{AS}} strings.
|
227 |
|
|
|
228 |
|
|
@emph{Warning!} The HPPA version of @code{.string} differs from the
|
229 |
|
|
usual @code{@value{AS}} definition: it does @emph{not} write a zero byte
|
230 |
|
|
after copying @var{str}.
|
231 |
|
|
|
232 |
|
|
@item .stringz "@var{str}"
|
233 |
|
|
Like @code{.string}, but appends a zero byte after copying @var{str} to object
|
234 |
|
|
file.
|
235 |
|
|
|
236 |
|
|
@item .subspa @var{name} [ ,@var{params} ]
|
237 |
|
|
@itemx .nsubspa @var{name} [ ,@var{params} ]
|
238 |
|
|
Similar to @code{.space}, but selects a subsection @var{name} within the
|
239 |
|
|
current section. You may only specify @var{params} when you create a
|
240 |
|
|
subsection (in the first instance of @code{.subspa} for this @var{name}).
|
241 |
|
|
|
242 |
|
|
If specified, the list @var{params} declares attributes of the subsection,
|
243 |
|
|
identified by keywords. The keywords recognized are @samp{quad=@var{expr}}
|
244 |
|
|
(``quadrant'' for this subsection), @samp{align=@var{expr}} (alignment for
|
245 |
|
|
beginning of this subsection; a power of two), @samp{access=@var{expr}} (value
|
246 |
|
|
for ``access rights'' field), @samp{sort=@var{expr}} (sorting order for this
|
247 |
|
|
subspace in link), @samp{code_only} (subsection contains only code),
|
248 |
|
|
@samp{unloadable} (subsection cannot be loaded into memory), @samp{comdat}
|
249 |
|
|
(subsection is comdat), @samp{common} (subsection is common block),
|
250 |
|
|
@samp{dup_comm} (subsection may have duplicate names), or @samp{zero}
|
251 |
|
|
(subsection is all zeros, do not write in object file).
|
252 |
|
|
|
253 |
|
|
@code{.nsubspa} always creates a new subspace with the given name, even
|
254 |
|
|
if one with the same name already exists.
|
255 |
|
|
|
256 |
|
|
@samp{comdat}, @samp{common} and @samp{dup_comm} can be used to implement
|
257 |
|
|
various flavors of one-only support when using the SOM linker. The SOM
|
258 |
|
|
linker only supports specific combinations of these flags. The details
|
259 |
|
|
are not documented. A brief description is provided here.
|
260 |
|
|
|
261 |
|
|
@samp{comdat} provides a form of linkonce support. It is useful for
|
262 |
|
|
both code and data subspaces. A @samp{comdat} subspace has a key symbol
|
263 |
|
|
marked by the @samp{is_comdat} flag or @samp{ST_COMDAT}. Only the first
|
264 |
|
|
subspace for any given key is selected. The key symbol becomes universal
|
265 |
|
|
in shared links. This is similar to the behavior of @samp{secondary_def}
|
266 |
|
|
symbols.
|
267 |
|
|
|
268 |
|
|
@samp{common} provides Fortran named common support. It is only useful
|
269 |
|
|
for data subspaces. Symbols with the flag @samp{is_common} retain this
|
270 |
|
|
flag in shared links. Referencing a @samp{is_common} symbol in a shared
|
271 |
|
|
library from outside the library doesn't work. Thus, @samp{is_common}
|
272 |
|
|
symbols must be output whenever they are needed.
|
273 |
|
|
|
274 |
|
|
@samp{common} and @samp{dup_comm} together provide Cobol common support.
|
275 |
|
|
The subspaces in this case must all be the same length. Otherwise, this
|
276 |
|
|
support is similar to the Fortran common support.
|
277 |
|
|
|
278 |
|
|
@samp{dup_comm} by itself provides a type of one-only support for code.
|
279 |
|
|
Only the first @samp{dup_comm} subspace is selected. There is a rather
|
280 |
|
|
complex algorithm to compare subspaces. Code symbols marked with the
|
281 |
|
|
@samp{dup_common} flag are hidden. This support was intended for "C++
|
282 |
|
|
duplicate inlines".
|
283 |
|
|
|
284 |
|
|
A simplified technique is used to mark the flags of symbols based on
|
285 |
|
|
the flags of their subspace. A symbol with the scope SS_UNIVERSAL and
|
286 |
|
|
type ST_ENTRY, ST_CODE or ST_DATA is marked with the corresponding
|
287 |
|
|
settings of @samp{comdat}, @samp{common} and @samp{dup_comm} from the
|
288 |
|
|
subspace, respectively. This avoids having to introduce additional
|
289 |
|
|
directives to mark these symbols. The HP assembler sets @samp{is_common}
|
290 |
|
|
from @samp{common}. However, it doesn't set the @samp{dup_common} from
|
291 |
|
|
@samp{dup_comm}. It doesn't have @samp{comdat} support.
|
292 |
|
|
|
293 |
|
|
@item .version "@var{str}"
|
294 |
|
|
Write @var{str} as version identifier in object code.
|
295 |
|
|
@end table
|
296 |
|
|
|
297 |
|
|
@node HPPA Opcodes
|
298 |
|
|
@section Opcodes
|
299 |
|
|
For detailed information on the HPPA machine instruction set, see
|
300 |
|
|
@cite{PA-RISC Architecture and Instruction Set Reference Manual}
|
301 |
|
|
(HP 09740-90039).
|