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* doc/{all.texi,as.texinfo}: Add documentation for HPPA port.

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gas/ChangeLog
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@ -1,3 +1,7 @@
Tue Jan 25 15:53:11 1994 Jeffrey A. Law (law@snake.cs.utah.edu)
* doc/{all.texi,as.texinfo}: Add documentation for HPPA port.
Mon Jan 24 19:18:23 1994 Ian Lance Taylor (ian@tweedledumb.cygnus.com)
* ecoff.c (ecoff_frob_symbol): New function. Put undefined

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gas/doc/all.texi
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@ -21,15 +21,14 @@
@set BOUT
@set COFF
@set ELF
@set SOM
@c CPUs of interest
@c ================
@set A29K
@set H8/300
@set H8/500
@c start Hitachi-SH
@set SH
@c end Hitachi-SH
@set I80386
@set I960
@set M680X0
@ -37,6 +36,7 @@
@set SPARC
@set VAX
@set VXWORKS
@set HPPA
@c Does this version of the assembler use the difference-table kluge?
@set DIFF-TBL-KLUGE

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gas/doc/as.texinfo
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@ -24,6 +24,9 @@
@ifset SH
@set H8
@end ifset
@ifset HPPA
@set abnormal-separator
@end ifset
@c ------------
@ifset GENERIC
@settitle Using @value{AS}
@ -150,6 +153,8 @@ code for @value{TARGET} architectures.
* Copying:: GNU GENERAL PUBLIC LICENSE
@end ifset
* Acknowledgements:: Who Did What
* Index:: Index
@end menu
@end ifinfo
@ -182,6 +187,9 @@ Here is a brief summary of how to invoke @code{@value{AS}}. For details,
@ifset H8
@c Hitachi family chips have no machine-dependent assembler options
@end ifset
@ifset HPPA
@c HPPA has no machine-dependent assembler options (yet).
@end ifset
@ifset SPARC
[ -Av6 | -Av7 | -Av8 | -Asparclite | -bump ]
@end ifset
@ -219,7 +227,8 @@ This option is accepted only for script compatibility with calls to
other assemblers; it has no effect on @code{@value{AS}}.
@item -f
``fast''---skip preprocessing (assume source is compiler output)
``fast''---skip whitespace and comment preprocessing (assume source is
compiler output)
@item -I @var{path}
Add @var{path} to the search list for @code{.include} directives
@ -477,6 +486,10 @@ On the @value{TARGET}, @code{@value{AS}} can be configured to produce either
On the @value{TARGET}, @code{@value{AS}} can be configured to produce either
@code{b.out} or COFF format object files.
@end ifset
@ifset HPPA
On the @value{TARGET}, @code{@value{AS}} can be configured to produce either
SOM or ELF format object files.
@end ifset
@end ifclear
@node Command Line
@ -752,7 +765,8 @@ likely that scripts written for other assemblers will also work with
@cindex trusted compiler
@cindex faster processing (@code{-f})
@samp{-f} should only be used when assembling programs written by a
(trusted) compiler. @samp{-f} stops the assembler from pre-processing
(trusted) compiler. @samp{-f} stops the assembler from doing whitespace
and comment pre-processing on
the input file(s) before assembling them. @xref{Pre-processing,
,Pre-processing}.
@ -815,6 +829,13 @@ This option tells @code{@value{AS}} to retain those @samp{L@dots{}} symbols
in the object file. Usually if you do this you also tell the linker
@code{@value{LD}} to preserve symbols whose names begin with @samp{L}.
By default, a local label is any label beginning with @samp{L}, but each
target is allowed to redefine the local label prefix.
@ifclear GENERIC
On some targets a local label begins with @samp{.L}; on the HPPA local labels
begin with @samp{L$}.
@end ifclear
@node o
@section Name the Object File: @code{-o}
@ -871,6 +892,11 @@ this option is only useful if you use sections named @samp{.text} and
@samp{.data}.
@end ifset
@ifset HPPA
@code{-R} is not supported for any of the HPPA targets . Using
@code{-R} will generate a warning from @code{@value{AS}}.
@end ifset
@node v
@section Announce Version: @code{-v}
@ -925,7 +951,7 @@ assembler, except that @code{@value{AS}} does not assemble Vax bit-fields.
@section Pre-Processing
@cindex preprocessing
The pre-processor:
The @code{@value{AS}} internal pre-processor:
@itemize @bullet
@cindex whitespace, removed by preprocessor
@item
@ -943,6 +969,13 @@ appropriate number of newlines.
converts character constants into the appropriate numeric values.
@end itemize
Note that it does not do macro processing, include file handling, or
anything else you may get from your C compiler's pre-processor. You can
do include file processing with the @code{.include} directive
(@pxref{Include,,@code{.include}}). Other ``CPP'' style pre-processing
can be done with the @sc{GNU} C compiler, by giving the input file a
@code{.S} suffix; see the compiler documentation for details.
Excess whitespace, comments, and character constants
cannot be used in the portions of the input text that are not
pre-processed.
@ -1012,6 +1045,9 @@ is considered a comment and is ignored. The line comment character is
@ifset H8/500
@samp{!} for the H8/500 family;
@end ifset
@ifset HPPA
@samp{;} for the HPPA;
@end ifset
@ifset SH
@samp{!} for the Hitachi SH;
@end ifset
@ -1097,6 +1133,12 @@ sign (@samp{@@}). The newline or at sign is considered part of the
preceding statement. Newlines and at signs within character constants
are an exception: they don't end statements.
@end ifset
@ifset HPPA
A @dfn{statement} ends at a newline character (@samp{\n}) or an exclamation
point (@samp{!}). The newline or exclamation point is considered part of the
preceding statement. Newlines and exclamation points within character
constants are an exception: they don't end statements.
@end ifset
@ifset H8
A @dfn{statement} ends at a newline character (@samp{\n}); or (for the
H8/300) a dollar sign (@samp{$}); or (for the
@ -1159,6 +1201,12 @@ A label is a symbol immediately followed by a colon (@code{:}).
Whitespace before a label or after a colon is permitted, but you may not
have whitespace between a label's symbol and its colon. @xref{Labels}.
@ifset HPPA
For HPPA targets, labels need not be immediately followed by a colon, but
the definition of a label must begin in column zero. This also implies that
only one label may be defined on each line.
@end ifset
@smallexample
label: .directive followed by something
another_label: # This is an empty statement.
@ -1269,6 +1317,14 @@ An octal character code. The numeric code is 3 octal digits.
For compatibility with other Unix systems, 8 and 9 are accepted as digits:
for example, @code{\008} has the value 010, and @code{\009} the value 011.
@ifset HPPA
@item \@code{x} @var{hex-digit} @var{hex-digit}
@cindex @code{\@var{xdd}} (hex character code)
@cindex hex character code (@code{\@var{xdd}})
A hex character code. The numeric code is 2 hexidecimal digits. Either
an upper or lower case @code{x} may be used.
@end ifset
@item \\
@cindex @code{\\} (@samp{\} character)
@cindex backslash (@code{\\})
@ -1413,6 +1469,9 @@ A flonum is written by writing (in order)
@itemize @bullet
@item
The digit @samp{0}.
@ifset HPPA
@samp{0} is optional on the HPPA.
@end ifset
@item
A letter, to tell @code{@value{AS}} the rest of the number is a flonum.
@ -1432,6 +1491,8 @@ one of the letters @samp{DFPRSX} (in upper or lower case).
On the Intel 960 architecture, the letter must be
one of the letters @samp{DFT} (in upper or lower case).
On the HPPA architecture, the letter must be @samp{E} (upper case only).
@end ifset
@ifclear GENERIC
@ifset A29K
@ -1443,6 +1504,9 @@ One of the letters @samp{DFPRSX} (in upper or lower case).
@ifset I960
One of the letters @samp{DFT} (in upper or lower case).
@end ifset
@ifset HPPA
On the HPPA architecture, the letter must be @samp{E} (upper case only).
@end ifset
@end ifclear
@item
@ -1572,9 +1636,33 @@ If you don't use any directives that place output in the @samp{.text}
or @samp{.data} sections, these sections will still exist, but will be empty.
@end ifset
@ifset HPPA
@ifset GENERIC
When @code{@value{AS}} generates SOM or ELF output for the HPPA,
@end ifset
@code{@value{AS}} can also generate whatever other named sections you
specify using the @samp{.space} and @samp{.subspace} directives. See
@cite{HP9000 Series 800 Assembly Language Reference Manual}
(HP 92432-90001) for details on the @samp{.space} and @samp{.subspace}
assembler directives.
@ifset SOM
Additionally, @code{@value{AS}} uses different names for the standard
text, data, and bss sections when generating SOM output. Program text
is placed into the @samp{$CODE$} section, data into @samp{$DATA$}, and
BSS into @samp{$BSS$}.
@end ifset
@end ifset
Within the object file, the text section starts at address @code{0}, the
data section follows, and the bss section follows the data section.
@ifset HPPA
When generating either SOM or ELF output files on the HPPA, the text
section starts at address @code{0}, the data section at address
@code{0x4000000}, and the bss section follows the data section.
@end ifset
To let @code{@value{LD}} know which data will change when the sections are
relocated, and how to change that data, @code{@value{AS}} also writes to the
object file details of the relocation needed. To perform relocation
@ -1651,7 +1739,7 @@ use of @code{@value{AS}} and have no meaning except during assembly.
@ifset aout-bout
@cindex text section
@cindex data section
@item text section
@itemx text section
@itemx data section
@end ifset
These sections hold your program. @code{@value{AS}} and @code{@value{LD}} treat them as
@ -1756,58 +1844,16 @@ value of every expression in your assembly language program to be a
section-relative address.
@table @b
@item absent
@cindex absent (internal section)
An expression was expected and none was found.
@item ASSEMBLER-INTERNAL-LOGIC-ERROR!
@cindex assembler internal logic error
An internal assembler logic error has been found. This means there is a
bug in the assembler.
@item bignum/flonum
@cindex bignum/flonum (internal section)
If a number can't be written as a C @code{int} constant (a bignum or a
flonum, but not an integer), it is recorded as belonging to this
``section''. @code{@value{AS}} has to remember that a flonum or a bignum
does not fit into 32 bits, and cannot be an argument (@pxref{Arguments})
in an expression: this is done by making a flonum or bignum be in a
separate internal section. This is purely for internal @code{@value{AS}}
convenience; bignum/flonum section behaves similarly to absolute
section.
@item pass1 section
@cindex pass1 (internal section)
The expression was impossible to evaluate in the first pass. The
assembler will attempt a second pass (second reading of the source) to
evaluate the expression. Your expression mentioned an undefined symbol
in a way that defies the one-pass (section + offset in section) assembly
process. No compiler need emit such an expression.
@quotation
@emph{Warning:} the second pass is currently not implemented. @code{@value{AS}}
will abort with an error message if one is required.
@end quotation
@item difference section
@cindex difference (internal section)
As an assist to the C compiler, expressions of the forms
@display
(@var{undefined symbol}) @minus{} (@var{expression})
@var{something} @minus{} (@var{undefined symbol})
(@var{undefined symbol}) @minus{} (@var{undefined symbol})
@end display
are permitted, and belong to the difference section. @code{@value{AS}}
re-evaluates such expressions after the source file has been read and
the symbol table built. If by that time there are no undefined symbols
in the expression then the expression assumes a new section. The
intention is to permit statements like
@samp{.word label - base_of_table}
to be assembled in one pass where both @code{label} and
@code{base_of_table} are undefined. This is useful for compiling C and
Algol switch statements, Pascal case statements, FORTRAN computed goto
statements and the like.
@item expr section
@cindex expr (internal section)
The assembler stores complex expression internally as combinations of
symbols. When it needs to represent an expression as a symbol, it puts
it in the expr section.
@c FIXME item debug
@c FIXME item transfer[t] vector preload
@c FIXME item transfer[t] vector postload
@ -1974,6 +2020,12 @@ operand. You are warned if you use the same symbol to represent two
different locations: the first definition overrides any other
definitions.
@ifset HPPA
On the HPPA, a @dfn{label} need not be immediately followed by a colon,
but instead must start in column zero. Only one @dfn{label} may be
defined on a single line.
@end ifset
@node Setting Symbols
@section Giving Symbols Other Values
@ -2133,6 +2185,9 @@ would want.
@ifset COFF
* COFF Symbols:: Symbol Attributes for COFF
@end ifset
@ifset SOM
* SOM Symbols:: Symbol Attributes for SOM
@end ifset
@end menu
@node Symbol Value
@ -2246,6 +2301,21 @@ The @code{@value{AS}} directives @code{.dim}, @code{.line}, @code{.scl},
information for COFF.
@end ifset
@ifset SOM
@node SOM Symbols
@subsection Symbol Attributes for SOM
@cindex SOM symbol attributes
@cindex symbol attributes, SOM
The SOM format supports a multitude of symbol attributes set with the
with the @code{.EXPORT} and @code{.IMPORT} directives.
The attributes are described in @cite{HP9000 Series 800 Assembly
Language Reference Manual} (HP 92432-90001) under the @code{IMPORT} and
@code{EXPORT} assembler directive documentation.
@end ifset
@node Expressions
@chapter Expressions
@ -2595,6 +2665,13 @@ advancement. For example @samp{.align 3} will advance the location
counter until it a multiple of 8. If the location counter is already a
multiple of 8, no change is needed.
@ifset HPPA
For the HPPA, the first expression (which must be absolute) is the
alignment request in bytes. For example @samp{.align 8} will advance
the location counter until it is a multiple of 8. If the location counter
is already a multiple of 8, no change is needed.
@end ifset
The second expression (also absolute) gives the value to be stored in
the padding bytes. It (and the comma) may be omitted. If it is
omitted, the padding bytes are zero.
@ -2656,6 +2733,11 @@ will allocate space for each @code{.comm} symbol that is at least as
long as the longest @code{.comm} request in any of the partial programs
linked. @var{length} is an absolute expression.
@ifset HPPA
The syntax for @code{.comm} differs slightly on the HPPA. The syntax is
@code{@var{symbol} .comm, @var{length}}; @var{symbol} is optional.
@end ifset
@node Data
@section @code{.data @var{subsection}}
@ -2796,6 +2878,11 @@ conditionally. @xref{If,,@code{.if}}.
This directive sets the value of @var{symbol} to @var{expression}.
It is synonymous with @samp{.set}; @pxref{Set,,@code{.set}}.
@ifset HPPA
The syntax for @code{equ} on the HPPA is
@code{@var{symbol} .equ @var{expression}}.
@end ifset
@node Extern
@section @code{.extern}
@ -2880,6 +2967,13 @@ from another partial program it is linked with.
Both spellings (@samp{.globl} and @samp{.global}) are accepted, for
compatibility with other assemblers.
@ifset HPPA
On the HPPA symbols are made visible to @code{@value{LD}} with the
@code{.EXPORT} directive. Using @code{.EXPORT} is necessary to provide
the linker with the correct symbol type information necessary for linking
in SOM
@end ifset
@node hword
@section @code{.hword @var{expressions}}
@ -3010,6 +3104,11 @@ section, so at run-time the bytes will start off zeroed. @var{Symbol}
is not declared global (@pxref{Global,,@code{.global}}), so is normally
not visible to @code{@value{LD}}.
@ifset HPPA
The syntax for @code{.lcomm} differs slightly on the HPPA. The syntax is
@code{@var{symbol} .lcomm, @var{length}}; @var{symbol} is optional.
@end ifset
@node Lflags
@section @code{.lflags}
@ -3290,6 +3389,11 @@ message if one is required.
If you @code{.set} a global symbol, the value stored in the object
file is the last value stored into it.
@ifset HPPA
The syntax for @code{set} on the HPPA is
@code{@var{symbol} .set @var{expression}}.
@end ifset
@node Short
@section @code{.short @var{expressions}}
@ -3365,6 +3469,13 @@ and @var{fill} are omitted, @var{fill} is assumed to be zero.
On the AMD 29K, this directive is ignored; it is accepted for
compatibility with other AMD 29K assemblers.
@ifset HPPA
@emph{Warning:} @code{.space} has a completely different meaning for HPPA
targets; use @code{.block} as a substitute. See @cite{HP9000 Series 800
Assembly Language Reference Manual} (HP 92432-90001) for the meaning of
the @code{.space} directive.
@end ifset
@quotation
@emph{Warning:} In most versions of the GNU assembler, the directive
@code{.space} has the effect of @code{.block} @xref{Machine Dependencies}.
@ -3619,6 +3730,9 @@ subject, see the hardware manufacturer's manual.
@ifset H8/500
* H8/500-Dependent:: Hitachi H8/500 Dependent Features
@end ifset
@ifset HPPA
* HPPA-Dependent:: HPPA Dependent Features
@end ifset
@ifset SH
* SH-Dependent:: Hitachi SH Dependent Features
@end ifset
@ -3639,11 +3753,11 @@ subject, see the hardware manufacturer's manual.
@end ifset
@end menu
@down
@lowersections
@end ifset
@c The following major nodes are *sections* in the GENERIC version, *chapters*
@c in single-cpu versions. This is mainly achieved by @down. There is a
@c in single-cpu versions. This is mainly achieved by @lowersections. There is a
@c peculiarity: to preserve cross-references, there must be a node called
@c "Machine Dependencies". Hence the conditional nodenames in each
@c major node below. Node defaulting in makeinfo requires adjacency of
@ -4165,7 +4279,7 @@ family.
* H8/500-Dependent:: Hitachi H8/500 Dependent Features
* SH-Dependent:: Hitachi SH Dependent Features
@end menu
@down
@lowersections
@end ifclear
@end ifset
@ -4770,6 +4884,108 @@ mov[:g] sz ea,rd
@end smallexample
@end ifset
@ifset HPPA
@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 backend for GNU 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 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 directives for the HPPA.
@cindex HPPA Syntax
@section HPPA Syntax
@node HPPA 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 compatability 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. @code{@value{AS}} will flag 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 Machine Directives
For detailed information on the HPPA machine instruction set, see
@cite{HP9000 Series 800 Assembly Language Reference Manual}
(HP 92432-90001).
@code{@value{AS}} does not support the following assembler directives
found in the HP manual:
@itemize @bullet
@item endm
@item enter
@item leave
@item listoff
@item liston
@item locct
@item macro
@end itemize
@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.
@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).
@end ifset
@ifset SH
@page
@node SH-Dependent
@ -5022,7 +5238,7 @@ stc SR,Rn
@ifset Hitachi-all
@ifclear GENERIC
@up
@raisesections
@end ifclear
@end ifset
@ -5340,6 +5556,7 @@ and the instruction pairs they may expand into:
@menu
* M68K-Opts:: M680x0 Options
* M68K-Syntax:: Syntax
* M68K-Moto-Syntax:: Motorola Syntax
* M68K-Float:: Floating Point
* M68K-Directives:: 680x0 Machine Directives
* M68K-opcodes:: Opcodes
@ -5381,18 +5598,21 @@ target.
@node M68K-Syntax
@section Syntax
@cindex @sc{mit}
This syntax for the Motorola 680x0 was developed at @sc{mit}.
@cindex M680x0 syntax
@cindex syntax, M680x0
@cindex M680x0 size modifiers
@cindex size modifiers, M680x0
The 680x0 version of @code{@value{AS}} uses syntax similar to the Sun assembler.
Size modifiers are appended directly to the end of the opcode without an
intervening period. For example, write @samp{movl} rather than
@samp{move.l}.
The 680x0 version of @code{@value{AS}} uses syntax similar to the Sun
assembler. Intervening periods are now ignored; for example, @samp{movl}
is equivalent to @samp{move.l}.
@ifset INTERNALS
If @code{@value{AS}} is compiled with SUN_ASM_SYNTAX defined, it will also allow
Sun-style local labels of the form @samp{1$} through @samp{$9}.
If @code{@value{AS}} is compiled with SUN_ASM_SYNTAX defined, it will
also allow Sun-style local labels of the form @samp{1$} through
@samp{$9}.
@end ifset
In the following table @dfn{apc} stands for any of the address
@ -5414,7 +5634,9 @@ The following addressing modes are understood:
@samp{a0} through @samp{a7}
@item Address Register Indirect
@samp{a0@@} through @samp{a7@@}
@samp{a0@@} through @samp{a7@@}@*
@samp{a7} is also known as @samp{sp}, i.e. the Stack Pointer. @code{a6}
is also known as @samp{fp}, the Frame Pointer.
@item Address Register Postincrement
@samp{a0@@+} through @samp{a7@@+}
@ -5461,6 +5683,57 @@ registers named @samp{a0} through @samp{a7}, et cetera. The @samp{%} is
always accepted, but is only required for some configurations, notably
@samp{m68k-coff}.
@node M68K-Moto-Syntax
@section Motorola Syntax
@cindex Motorola syntax for the 680x0
@cindex alternate syntax for the 680x0
The standard Motorola syntax for this chip differs from the syntax
already discussed (@pxref{M68K-Syntax,,Syntax}). @code{@value{AS}} can
accept both kinds of syntax, even within a single instruction. The
syntaxes are fully compatible, because the Motorola syntax never uses
the @samp{@@} character and the @sc{mit} syntax always does, except in
cases where the syntaxes are identical.
@cindex M680x0 syntax
@cindex syntax, M680x0
In particular, you may write or generate M68K assembler with the
following conventions:
(In the following table @dfn{apc} stands for any of the address
registers (@samp{a0} through @samp{a7}), nothing, (@samp{}), the
Program Counter (@samp{pc}), or the zero-address relative to the
program counter (@samp{zpc}).)
@cindex M680x0 addressing modes
@cindex addressing modes, M680x0
The following additional addressing modes are understood:
@table @dfn
@item Address Register Indirect
@samp{a0} through @samp{a7}@*
@samp{a7} is also known as @samp{sp}, i.e. the Stack Pointer. @code{a6}
is also known as @samp{fp}, the Frame Pointer.
@item Address Register Postincrement
@samp{(a0)+} through @samp{(a7)+}
@item Address Register Predecrement
@samp{-(a0)} through @samp{-(a7)}
@item Indirect Plus Offset
@samp{@var{digits}(@var{apc})}
@item Index
@samp{@var{digits}(@var{apc},(@var{register}.@var{size}*@var{scale})}@*
or @samp{(@var{apc},@var{register}.@var{size}*@var{scale})}@*
In either case, @var{size} and @var{scale} are optional
(@var{scale} defaults to @samp{1}, @var{size} defaults to @samp{l}).
@var{scale} can be @samp{1}, @samp{2}, @samp{4}, or @samp{8}.
@var{size} can be @samp{w} or @samp{l}. @var{scale} is only supported
on the 68020 and greater.
@end table
@node M68K-Float
@section Floating Point
@ -6646,7 +6919,7 @@ described elsewhere in the manual.
@ifset GENERIC
@c reverse effect of @down at top of generic Machine-Dep chapter
@up
@raisesections
@end ifset
@ifset INTERNALS
@ -7384,17 +7657,16 @@ currently assembling into.
@section External functions will you need
You will find the following external functions useful (or
indispensable) when you're writing the machine-dependent part
of the assembler.
You will find the following external functions useful (or indispensable) when
you're writing the machine-dependent part of the assembler.
@table @code
@item char *frag_more(int bytes)
This function allocates @var{bytes} more bytes in the current
frag (or starts a new frag, if it can't expand the current frag
any more.) for you to store some object-file bytes in. It
returns a pointer to the bytes, ready for you to store data in.
This function allocates @var{bytes} more bytes in the current frag (or starts a
new frag, if it can't expand the current frag any more.) for you to store some
object-file bytes in. It returns a pointer to the bytes, ready for you to
store data in.
@item void fix_new(fragS *frag, int where, short size, symbolS *add_symbol, symbolS *sub_symbol, long offset, int pcrel)
This function stores a relocation fixup to be acted on later.
@ -7423,70 +7695,61 @@ addressing mode used by this frag changes. It typically points into the
that @code{md_convert_frag()}, may have to change.@refill
@item void frag_wane(fragS *fragPTR)
This function is useful from within @code{md_convert_frag}. It
changes a frag to type rs_fill, and sets the variable-sized
piece of the frag to zero. The frag will never change in size
again.
This function is useful from within @code{md_convert_frag}. It changes a frag
to type rs_fill, and sets the variable-sized piece of the frag to zero. The
frag will never change in size again.
@item segT expression(expressionS *retval)
(@var{segT} is defined in @file{as.h}; @var{expressionS} is defined in @file{expr.h})
This function parses the string pointed to by the external char
pointer @var{input_line_pointer}, and returns the section-type
of the expression. It also stores the results in the
@var{expressionS} pointed to by @var{retval}.
@var{input_line_pointer} is advanced to point past the end of
the expression. (@var{input_line_pointer} is used by other
parts of the assembler. If you modify it, be sure to restore
it to its original value.)
(@var{segT} is defined in @file{as.h}; @var{expressionS} is defined in
@file{expr.h}) This function parses the string pointed to by the external char
pointer @var{input_line_pointer}, and returns the section-type of the symbol
used in the expression, if any. It stores the results in the @var{expressionS}
pointed to by @var{retval}. @var{input_line_pointer} is advanced to point past
the end of the expression. (@var{input_line_pointer} is used by other parts of
the assembler. If you modify it, be sure to restore it to its original value.)
@item as_warn(char *message,@dots{})
If warning messages are disabled, this function does nothing.
Otherwise, it prints out the current file name, and the current
line number, then uses @code{fprintf} to print the
@var{message} and any arguments it was passed.
If warning messages are disabled, this function does nothing. Otherwise, it
prints out the current file name, and the current line number, then uses
@code{fprintf} to print the @var{message} and any arguments it was passed.
@item as_bad(char *message,@dots{})
This function should be called when @code{@value{AS}} encounters
conditions that are bad enough that @code{@value{AS}} should not
produce an object file, but should continue reading input and
printing warning and bad error messages.
This function should be called when @code{@value{AS}} encounters conditions
that are bad enough that @code{@value{AS}} should not produce an object file,
but should continue reading input and printing warning and bad error messages.
@item as_fatal(char *message,@dots{})
This function prints out the current file name and line number,
prints the word @samp{FATAL:}, then uses @code{fprintf} to
print the @var{message} and any arguments it was passed. Then
the assembler exits. This function should only be used for
serious, unrecoverable errors.
This function prints out the current file name and line number, prints the word
@samp{FATAL:}, then uses @code{fprintf} to print the @var{message} and any
arguments it was passed. Then the assembler exits. This function should only
be used for serious, unrecoverable errors.
@item void float_const(int float_type)
This function reads floating-point constants from the current
input line, and calls @code{md_atof} to assemble them. It is
useful as the function to call for the directives
@samp{.single}, @samp{.double}, @samp{.float}, etc.
This function reads floating-point constants from the current input line, and
calls @code{md_atof} to assemble them. It is useful as the function to call
for the directives @samp{.single}, @samp{.double}, @samp{.float}, etc.
@var{float_type} must be a character from @var{FLT_CHARS}.
@item void demand_empty_rest_of_line(void);
This function can be used by machine-dependent directives to
make sure the rest of the input line is empty. It prints a
warning message if there are additional characters on the line.
This function can be used by machine-dependent directives to make sure the rest
of the input line is empty. It prints a warning message if there are
additional characters on the line.
@item long int get_absolute_expression(void)
This function can be used by machine-dependent directives to
read an absolute number from the current input line. It
returns the result. If it isn't given an absolute expression,
it prints a warning message and returns zero.
This function can be used by machine-dependent directives to read an absolute
number from the current input line. It returns the result. If it isn't given
an absolute expression, it prints a warning message and returns zero.
@end table
@section The concept of Frags
This assembler works to optimize the size of certain addressing
modes. (e.g. branch instructions) This means the size of many
pieces of object code cannot be determined until after assembly
is finished. (This means that the addresses of symbols cannot be
determined until assembly is finished.) In order to do this,
@code{@value{AS}} stores the output bytes as @dfn{frags}.
This assembler works to optimize the size of certain addressing modes.
(e.g. branch instructions) This means the size of many pieces of object code
cannot be determined until after assembly is finished. (This means that the
addresses of symbols cannot be determined until assembly is finished.) In
order to do this, @code{@value{AS}} stores the output bytes as @dfn{frags}.
Here is the definition of a frag (from @file{as.h})
@smallexample
@ -7521,53 +7784,133 @@ rs_org
rs_machine_dependent
@item fr_substate
This stores the type of machine-dependent frag this is. (what
kind of addressing mode is being used, and what size is being
tried/will fit/etc.
This stores the type of machine-dependent frag this is. (what kind of
addressing mode is being used, and what size is being tried/will fit/etc.
@item fr_address
@var{fr_address} is only valid after relaxation is finished.
Before relaxation, the only way to store an address is (pointer
to frag containing the address) plus (offset into the frag).
@var{fr_address} is only valid after relaxation is finished. Before
relaxation, the only way to store an address is (pointer to frag containing the
address) plus (offset into the frag).
@item fr_offset
This contains a number, whose meaning depends on the type of
the frag.
for machine_dependent frags, this contains the offset from
fr_symbol that the frag wants to go to. Thus, for branch
instructions it is usually zero. (unless the instruction was
@samp{jba foo+12} or something like that.)
This contains a number, whose meaning depends on the type of the frag. for
machine_dependent frags, this contains the offset from fr_symbol that the frag
wants to go to. Thus, for branch instructions it is usually zero. (unless the
instruction was @samp{jba foo+12} or something like that.)
@item fr_symbol
for machine_dependent frags, this points to the symbol the frag
needs to reach.
for machine_dependent frags, this points to the symbol the frag needs to reach.
@item fr_opcode
This points to the location in the frag (or in a previous frag)
of the opcode for the instruction that caused this to be a frag.
@var{fr_opcode} is needed if the actual opcode must be changed
in order to use a different form of the addressing mode.
(For example, if a conditional branch only comes in size tiny,
a large-size branch could be implemented by reversing the sense
of the test, and turning it into a tiny branch over a large jump.
This would require changing the opcode.)
This points to the location in the frag (or in a previous frag) of the opcode
for the instruction that caused this to be a frag. @var{fr_opcode} is needed
if the actual opcode must be changed in order to use a different form of the
addressing mode. (For example, if a conditional branch only comes in size
tiny, a large-size branch could be implemented by reversing the sense of the
test, and turning it into a tiny branch over a large jump. This would require
changing the opcode.)
@var{fr_literal} is a variable-size array that contains the
actual object bytes. A frag consists of a fixed size piece of
object data, (which may be zero bytes long), followed by a
piece of object data whose size may not have been determined
yet. Other information includes the type of the frag (which
@var{fr_literal} is a variable-size array that contains the actual object
bytes. A frag consists of a fixed size piece of object data, (which may be
zero bytes long), followed by a piece of object data whose size may not have
been determined yet. Other information includes the type of the frag (which
controls how it is relaxed),
@item fr_next
This is the next frag in the singly-linked list. This is
usually only needed by the machine-independent part of
@code{@value{AS}}.
This is the next frag in the singly-linked list. This is usually only needed
by the machine-independent part of @code{@value{AS}}.
@end table
@end ifset
@node Acknowledgements
@chapter Acknowledgements
If you've contributed to @code{@value{AS}} and your name isn't listed here, it
is not meant as a slight. We just don't know about it. Send mail to the
maintainer, and we'll correct the situation. Currently (June 1993), the
maintainer is Ken Raeburn (email address @code{raeburn@@cygnus.com}).
Dean Elsner wrote the original GNU assembler for the VAX.@footnote{Any more
details?}
Jay Fenlason maintained GAS for a while, adding support for gdb-specific debug
information and the 68k series machines, most of the preprocessing pass, and
extensive changes in messages.c, input-file.c, write.c.
K. Richard Pixley maintained GAS for a while, adding various enhancements and
many bug fixes, including merging support for several processors, breaking GAS
up to handle multiple object file format backends (including heavy rewrite,
testing, an integration of the coff and b.out backends), adding configuration
including heavy testing and verification of cross assemblers and file splits
and renaming, converted GAS to strictly ansi C including full prototypes, added
support for m680[34]0 & cpu32, considerable work on i960 including a COFF port
(including considerable amounts of reverse engineering), a SPARC opcode file
rewrite, DECstation, rs6000, and hp300hpux host ports, updated "know"
assertions and made them work, much other reorganization, cleanup, and lint.
Ken Raeburn wrote the high-level BFD interface code to replace most of the code
in format-specific I/O modules.
The original VMS support was contributed by David L. Kashtan. Eric Youngdale
has done much work with it since.
The Intel 80386 machine description was written by Eliot Dresselhaus.
Minh Tran-Le at IntelliCorp contributed some AIX 386 support.
The Motorola 88k machine description was contributed by Devon Bowen of Buffalo
University and Torbjorn Granlund of the Swedish Institute of Computer Science.
Keith Knowles at the Open Software Foundation wrote the original MIPS back end
(tc-mips.c, tc-mips.h), and contributed Rose format support (which hasn't been
merged in yet). Ralph Campbell worked with the MIPS code to support a.out
format.
Support for the Zilog Z8k and Hitachi H8/300 and H8/500 processors (tc-z8k,
tc-h8300, tc-h8500), and IEEE 695 object file format (obj-ieee), was written by
Steve Chamberlain of Cygnus Support. Steve also modified the COFF back end to
use BFD for some low-level operations, for use with the H8/300 and AMD 29k
targets.
John Gilmore built the AMD 29000 support, added .include support, and
simplified the configuration of which versions accept which pseudo-ops. He
updated the 68k machine description so that Motorola's opcodes always produced
fixed-size instructions (e.g. jsr), while synthetic instructions remained
shrinkable (jbsr). John fixed many bugs, including true tested
cross-compilation support, and one bug in relaxation that took a week and
required the apocryphal one-bit fix.
Ian Lance Taylor of Cygnus Support merged the Motorola and MIT syntaxes for the
68k, completed support for some COFF targets (68k, i386 SVR3, and SCO Unix),
and made a few other minor patches.
Steve Chamberlain made @code{@value{AS}} able to generate listings.
Support for the HP9000/300 was contributed by Hewlett-Packard.
GAS and BFD support for the native HPPA object format (SOM) along with
a fairly extensive HPPA testsuite (for both SOM and ELF object formats)
was written by Jeff Law. This work was supported by both the Center for
Software Science at the University of Utah and Cygnus Support.
Support for ELF format files has been worked on by Mark Eichin of Cygnus
Support (original, incomplete implementation for SPARC), Pete Hoogenboom and
Jeff Law at the University of Utah (HPPA mainly), Michael Meissner of the Open
Software Foundation (i386 mainly), and Ken Raeburn of Cygnus Support (sparc,
and some initial 64-bit support).
Several engineers at Cygnus Support have also provided many small bug fixes and
configuration enhancements.
Many others have contributed large or small bugfixes and enhancements. If
you've contributed significant work and are not mentioned on this list, and
want to be, let us know. Some of the history has been lost; we aren't
intentionally leaving anyone out.
@ifset GENERIC
@node Copying
@unnumbered
@include gpl.texinfo
@end ifset
@ -7578,3 +7921,6 @@ usually only needed by the machine-independent part of
@contents
@bye
@c Local Variables:
@c fill-column: 79
@c End: