gas/doc/c-i960.texi - third_party/gdb - Git at Google

 @c Copyright (C) 1991-2016 Free Software Foundation, Inc.
 @c This is part of the GAS manual.
 @c For copying conditions, see the file as.texinfo.
 @ifset GENERIC
 @page
 @node i960-Dependent
 @chapter Intel 80960 Dependent Features
 @end ifset
 @ifclear GENERIC
 @node Machine Dependencies
 @chapter Intel 80960 Dependent Features
 @end ifclear

 @cindex i960 support
 @menu
 * Options-i960::                i960 Command-line Options
 * Floating Point-i960::         Floating Point
 * Directives-i960::             i960 Machine Directives
 * Opcodes for i960::            i960 Opcodes
 * Syntax of i960::              i960 Syntax
 @end menu

 @c FIXME! Add Syntax sec with discussion of bitfields here, at least so
 @c long as they're not turned on for other machines than 960.

 @node Options-i960

 @section i960 Command-line Options

 @cindex i960 options
 @cindex options, i960
 @table @code

 @cindex i960 architecture options
 @cindex architecture options, i960
 @cindex @code{-A} options, i960
 @item -ACA | -ACA_A | -ACB | -ACC | -AKA | -AKB | -AKC | -AMC
 Select the 80960 architecture.  Instructions or features not supported
 by the selected architecture cause fatal errors.

 @samp{-ACA} is equivalent to @samp{-ACA_A}; @samp{-AKC} is equivalent to
 @samp{-AMC}.  Synonyms are provided for compatibility with other tools.

 If you do not specify any of these options, @code{@value{AS}} generates code
 for any instruction or feature that is supported by @emph{some} version of the
 960 (even if this means mixing architectures!).  In principle,
 @code{@value{AS}} attempts to deduce the minimal sufficient processor type if
 none is specified; depending on the object code format, the processor type may
 be recorded in the object file.  If it is critical that the @code{@value{AS}}
 output match a specific architecture, specify that architecture explicitly.

 @cindex @code{-b} option, i960
 @cindex branch recording, i960
 @cindex i960 branch recording
 @item -b
 Add code to collect information about conditional branches taken, for
 later optimization using branch prediction bits.  (The conditional branch
 instructions have branch prediction bits in the CA, CB, and CC
 architectures.)  If @var{BR} represents a conditional branch instruction,
 the following represents the code generated by the assembler when
 @samp{-b} is specified:

 @smallexample
         call    @var{increment routine}
         .word   0       # pre-counter
 Label:  @var{BR}
         call    @var{increment routine}
         .word   0       # post-counter
 @end smallexample

 The counter following a branch records the number of times that branch
 was @emph{not} taken; the difference between the two counters is the
 number of times the branch @emph{was} taken.

 @cindex @code{gbr960}, i960 postprocessor
 @cindex branch statistics table, i960
 A table of every such @code{Label} is also generated, so that the
 external postprocessor @code{gbr960} (supplied by Intel) can locate all
 the counters.  This table is always labeled @samp{__BRANCH_TABLE__};
 this is a local symbol to permit collecting statistics for many separate
 object files.  The table is word aligned, and begins with a two-word
 header.  The first word, initialized to 0, is used in maintaining linked
 lists of branch tables.  The second word is a count of the number of
 entries in the table, which follow immediately: each is a word, pointing
 to one of the labels illustrated above.

 @c TEXI2ROFF-KILL
 @ifinfo
 @c END TEXI2ROFF-KILL
 @example
  +------------+------------+------------+ ... +------------+
  |            |            |            |     |            |
  |  *NEXT     |  COUNT: N  | *BRLAB 1   |     | *BRLAB N   |
  |            |            |            |     |            |
  +------------+------------+------------+ ... +------------+

                __BRANCH_TABLE__ layout
 @end example
 @c TEXI2ROFF-KILL
 @end ifinfo
 @need 2000
 @tex
 \vskip 1pc
 \line{\leftskip=0pt\hskip\tableindent
 \boxit{2cm}{\tt *NEXT}\boxit{2cm}{\tt COUNT: \it N}\boxit{2cm}{\tt
 *BRLAB 1}\ibox{1cm}{\quad\dots}\boxit{2cm}{\tt *BRLAB \it N}\hfil}
 \centerline{\it {\tt \_\_BRANCH\_TABLE\_\_} layout}
 @end tex
 @c END TEXI2ROFF-KILL

 The first word of the header is used to locate multiple branch tables,
 since each object file may contain one. Normally the links are
 maintained with a call to an initialization routine, placed at the
 beginning of each function in the file.  The @sc{gnu} C compiler
 generates these calls automatically when you give it a @samp{-b} option.
 For further details, see the documentation of @samp{gbr960}.

 @cindex @code{-no-relax} option, i960
 @item -no-relax
 Normally, Compare-and-Branch instructions with targets that require
 displacements greater than 13 bits (or that have external targets) are
 replaced with the corresponding compare (or @samp{chkbit}) and branch
 instructions.  You can use the @samp{-no-relax} option to specify that
 @code{@value{AS}} should generate errors instead, if the target displacement
 is larger than 13 bits.

 This option does not affect the Compare-and-Jump instructions; the code
 emitted for them is @emph{always} adjusted when necessary (depending on
 displacement size), regardless of whether you use @samp{-no-relax}.
 @end table

 @node Floating Point-i960
 @section Floating Point

 @cindex floating point, i960 (@sc{ieee})
 @cindex i960 floating point (@sc{ieee})
 @code{@value{AS}} generates @sc{ieee} floating-point numbers for the directives
 @samp{.float}, @samp{.double}, @samp{.extended}, and @samp{.single}.

 @node Directives-i960
 @section i960 Machine Directives

 @cindex machine directives, i960
 @cindex i960 machine directives

 @table @code
 @cindex @code{bss} directive, i960
 @item .bss @var{symbol}, @var{length}, @var{align}
 Reserve @var{length} bytes in the bss section for a local @var{symbol},
 aligned to the power of two specified by @var{align}.  @var{length} and
 @var{align} must be positive absolute expressions.  This directive
 differs from @samp{.lcomm} only in that it permits you to specify
 an alignment.  @xref{Lcomm,,@code{.lcomm}}.
 @end table

 @table @code
 @cindex @code{extended} directive, i960
 @item .extended @var{flonums}
 @code{.extended} expects zero or more flonums, separated by commas; for
 each flonum, @samp{.extended} emits an @sc{ieee} extended-format (80-bit)
 floating-point number.

 @cindex @code{leafproc} directive, i960
 @item .leafproc @var{call-lab}, @var{bal-lab}
 You can use the @samp{.leafproc} directive in conjunction with the
 optimized @code{callj} instruction to enable faster calls of leaf
 procedures.  If a procedure is known to call no other procedures, you
 may define an entry point that skips procedure prolog code (and that does
 not depend on system-supplied saved context), and declare it as the
 @var{bal-lab} using @samp{.leafproc}.  If the procedure also has an
 entry point that goes through the normal prolog, you can specify that
 entry point as @var{call-lab}.

 A @samp{.leafproc} declaration is meant for use in conjunction with the
 optimized call instruction @samp{callj}; the directive records the data
 needed later to choose between converting the @samp{callj} into a
 @code{bal} or a @code{call}.

 @var{call-lab} is optional; if only one argument is present, or if the
 two arguments are identical, the single argument is assumed to be the
 @code{bal} entry point.

 @cindex @code{sysproc} directive, i960
 @item .sysproc @var{name}, @var{index}
 The @samp{.sysproc} directive defines a name for a system procedure.
 After you define it using @samp{.sysproc}, you can use @var{name} to
 refer to the system procedure identified by @var{index} when calling
 procedures with the optimized call instruction @samp{callj}.

 Both arguments are required; @var{index} must be between 0 and 31
 (inclusive).
 @end table

 @node Opcodes for i960
 @section i960 Opcodes

 @cindex opcodes, i960
 @cindex i960 opcodes
 All Intel 960 machine instructions are supported;
 @pxref{Options-i960,,i960 Command-line Options} for a discussion of
 selecting the instruction subset for a particular 960
 architecture.@refill

 Some opcodes are processed beyond simply emitting a single corresponding
 instruction: @samp{callj}, and Compare-and-Branch or Compare-and-Jump
 instructions with target displacements larger than 13 bits.

 @menu
 * callj-i960::                  @code{callj}
 * Compare-and-branch-i960::     Compare-and-Branch
 @end menu

 @node callj-i960
 @subsection @code{callj}

 @cindex @code{callj}, i960 pseudo-opcode
 @cindex i960 @code{callj} pseudo-opcode
 You can write @code{callj} to have the assembler or the linker determine
 the most appropriate form of subroutine call: @samp{call},
 @samp{bal}, or @samp{calls}.  If the assembly source contains
 enough information---a @samp{.leafproc} or @samp{.sysproc} directive
 defining the operand---then @code{@value{AS}} translates the
 @code{callj}; if not, it simply emits the @code{callj}, leaving it
 for the linker to resolve.

 @node Compare-and-branch-i960
 @subsection Compare-and-Branch

 @cindex i960 compare/branch instructions
 @cindex compare/branch instructions, i960
 The 960 architectures provide combined Compare-and-Branch instructions
 that permit you to store the branch target in the lower 13 bits of the
 instruction word itself.  However, if you specify a branch target far
 enough away that its address won't fit in 13 bits, the assembler can
 either issue an error, or convert your Compare-and-Branch instruction
 into separate instructions to do the compare and the branch.

 @cindex compare and jump expansions, i960
 @cindex i960 compare and jump expansions
 Whether @code{@value{AS}} gives an error or expands the instruction depends
 on two choices you can make: whether you use the @samp{-no-relax} option,
 and whether you use a ``Compare and Branch'' instruction or a ``Compare
 and Jump'' instruction.  The ``Jump'' instructions are @emph{always}
 expanded if necessary; the ``Branch'' instructions are expanded when
 necessary @emph{unless} you specify @code{-no-relax}---in which case
 @code{@value{AS}} gives an error instead.

 These are the Compare-and-Branch instructions, their ``Jump'' variants,
 and the instruction pairs they may expand into:

 @c TEXI2ROFF-KILL
 @ifinfo
 @c END TEXI2ROFF-KILL
 @example
         Compare and
      Branch      Jump       Expanded to
      ------    ------       ------------
         bbc                 chkbit; bno
         bbs                 chkbit; bo
      cmpibe    cmpije       cmpi; be
      cmpibg    cmpijg       cmpi; bg
     cmpibge   cmpijge       cmpi; bge
      cmpibl    cmpijl       cmpi; bl
     cmpible   cmpijle       cmpi; ble
     cmpibno   cmpijno       cmpi; bno
     cmpibne   cmpijne       cmpi; bne
      cmpibo    cmpijo       cmpi; bo
      cmpobe    cmpoje       cmpo; be
      cmpobg    cmpojg       cmpo; bg
     cmpobge   cmpojge       cmpo; bge
      cmpobl    cmpojl       cmpo; bl
     cmpoble   cmpojle       cmpo; ble
     cmpobne   cmpojne       cmpo; bne
 @end example
 @c TEXI2ROFF-KILL
 @end ifinfo
 @tex
 \hskip\tableindent
 \halign{\hfil {\tt #}\quad&\hfil {\tt #}\qquad&{\tt #}\hfil\cr
 \omit{\hfil\it Compare and\hfil}\span\omit&\cr
 {\it Branch}&{\it Jump}&{\it Expanded to}\cr
         bbc&                 & chkbit; bno\cr
         bbs&                 & chkbit; bo\cr
      cmpibe&    cmpije&       cmpi; be\cr
      cmpibg&    cmpijg&       cmpi; bg\cr
     cmpibge&   cmpijge&       cmpi; bge\cr
      cmpibl&    cmpijl&       cmpi; bl\cr
     cmpible&   cmpijle&       cmpi; ble\cr
     cmpibno&   cmpijno&       cmpi; bno\cr
     cmpibne&   cmpijne&       cmpi; bne\cr
      cmpibo&    cmpijo&       cmpi; bo\cr
      cmpobe&    cmpoje&       cmpo; be\cr
      cmpobg&    cmpojg&       cmpo; bg\cr
     cmpobge&   cmpojge&       cmpo; bge\cr
      cmpobl&    cmpojl&       cmpo; bl\cr
     cmpoble&   cmpojle&       cmpo; ble\cr
     cmpobne&   cmpojne&       cmpo; bne\cr}
 @end tex
 @c END TEXI2ROFF-KILL

 @node Syntax of i960
 @section Syntax for the i960
 @menu
 * i960-Chars::                Special Characters
 @end menu

 @node i960-Chars
 @subsection Special Characters

 @cindex line comment character, i960
 @cindex i960 line comment character
 The presence of a @samp{#} on a line indicates the start of a comment
 that extends to the end of the current line.

 If a @samp{#} appears as the first character of a line, the whole line
 is treated as a comment, but in this case the line can also be a
 logical line number directive (@pxref{Comments}) or a
 preprocessor control command (@pxref{Preprocessing}).

 @cindex line separator, i960
 @cindex statement separator, i960
 @cindex i960 line separator
 The @samp{;} character can be used to separate statements on the same
 line.
	@c Copyright (C) 1991-2016 Free Software Foundation, Inc.
	@c This is part of the GAS manual.
	@c For copying conditions, see the file as.texinfo.
	@ifset GENERIC
	@page
	@node i960-Dependent
	@chapter Intel 80960 Dependent Features
	@end ifset
	@ifclear GENERIC
	@node Machine Dependencies
	@chapter Intel 80960 Dependent Features
	@end ifclear

	@cindex i960 support
	@menu
	* Options-i960:: i960 Command-line Options
	* Floating Point-i960:: Floating Point
	* Directives-i960:: i960 Machine Directives
	* Opcodes for i960:: i960 Opcodes
	* Syntax of i960:: i960 Syntax
	@end menu

	@c FIXME! Add Syntax sec with discussion of bitfields here, at least so
	@c long as they're not turned on for other machines than 960.

	@node Options-i960

	@section i960 Command-line Options

	@cindex i960 options
	@cindex options, i960
	@table @code

	@cindex i960 architecture options
	@cindex architecture options, i960
	@cindex @code{-A} options, i960
	@item -ACA \| -ACA_A \| -ACB \| -ACC \| -AKA \| -AKB \| -AKC \| -AMC
	Select the 80960 architecture. Instructions or features not supported
	by the selected architecture cause fatal errors.

	@samp{-ACA} is equivalent to @samp{-ACA_A}; @samp{-AKC} is equivalent to
	@samp{-AMC}. Synonyms are provided for compatibility with other tools.

	If you do not specify any of these options, @code{@value{AS}} generates code
	for any instruction or feature that is supported by @emph{some} version of the
	960 (even if this means mixing architectures!). In principle,
	@code{@value{AS}} attempts to deduce the minimal sufficient processor type if
	none is specified; depending on the object code format, the processor type may
	be recorded in the object file. If it is critical that the @code{@value{AS}}
	output match a specific architecture, specify that architecture explicitly.

	@cindex @code{-b} option, i960
	@cindex branch recording, i960
	@cindex i960 branch recording
	@item -b
	Add code to collect information about conditional branches taken, for
	later optimization using branch prediction bits. (The conditional branch
	instructions have branch prediction bits in the CA, CB, and CC
	architectures.) If @var{BR} represents a conditional branch instruction,
	the following represents the code generated by the assembler when
	@samp{-b} is specified:

	@smallexample
	call @var{increment routine}
	.word 0 # pre-counter
	Label: @var{BR}
	call @var{increment routine}
	.word 0 # post-counter
	@end smallexample

	The counter following a branch records the number of times that branch
	was @emph{not} taken; the difference between the two counters is the
	number of times the branch @emph{was} taken.

	@cindex @code{gbr960}, i960 postprocessor
	@cindex branch statistics table, i960
	A table of every such @code{Label} is also generated, so that the
	external postprocessor @code{gbr960} (supplied by Intel) can locate all
	the counters. This table is always labeled @samp{__BRANCH_TABLE__};
	this is a local symbol to permit collecting statistics for many separate
	object files. The table is word aligned, and begins with a two-word
	header. The first word, initialized to 0, is used in maintaining linked
	lists of branch tables. The second word is a count of the number of
	entries in the table, which follow immediately: each is a word, pointing
	to one of the labels illustrated above.

	@c TEXI2ROFF-KILL
	@ifinfo
	@c END TEXI2ROFF-KILL
	@example
	+------------+------------+------------+ ... +------------+
	\| \| \| \| \| \|
	\| NEXT \| COUNT: N \| BRLAB 1 \| \| *BRLAB N \|
	\| \| \| \| \| \|
	+------------+------------+------------+ ... +------------+

	__BRANCH_TABLE__ layout
	@end example
	@c TEXI2ROFF-KILL
	@end ifinfo
	@need 2000
	@tex
	\vskip 1pc
	\line{\leftskip=0pt\hskip\tableindent
	\boxit{2cm}{\tt *NEXT}\boxit{2cm}{\tt COUNT: \it N}\boxit{2cm}{\tt
	BRLAB 1}\ibox{1cm}{\quad\dots}\boxit{2cm}{\tt BRLAB \it N}\hfil}
	\centerline{\it {\tt \_\_BRANCH\_TABLE\_\_} layout}
	@end tex
	@c END TEXI2ROFF-KILL

	The first word of the header is used to locate multiple branch tables,
	since each object file may contain one. Normally the links are
	maintained with a call to an initialization routine, placed at the
	beginning of each function in the file. The @sc{gnu} C compiler
	generates these calls automatically when you give it a @samp{-b} option.
	For further details, see the documentation of @samp{gbr960}.

	@cindex @code{-no-relax} option, i960
	@item -no-relax
	Normally, Compare-and-Branch instructions with targets that require
	displacements greater than 13 bits (or that have external targets) are
	replaced with the corresponding compare (or @samp{chkbit}) and branch
	instructions. You can use the @samp{-no-relax} option to specify that
	@code{@value{AS}} should generate errors instead, if the target displacement
	is larger than 13 bits.

	This option does not affect the Compare-and-Jump instructions; the code
	emitted for them is @emph{always} adjusted when necessary (depending on
	displacement size), regardless of whether you use @samp{-no-relax}.
	@end table

	@node Floating Point-i960
	@section Floating Point

	@cindex floating point, i960 (@sc{ieee})
	@cindex i960 floating point (@sc{ieee})
	@code{@value{AS}} generates @sc{ieee} floating-point numbers for the directives
	@samp{.float}, @samp{.double}, @samp{.extended}, and @samp{.single}.

	@node Directives-i960
	@section i960 Machine Directives

	@cindex machine directives, i960
	@cindex i960 machine directives

	@table @code
	@cindex @code{bss} directive, i960
	@item .bss @var{symbol}, @var{length}, @var{align}
	Reserve @var{length} bytes in the bss section for a local @var{symbol},
	aligned to the power of two specified by @var{align}. @var{length} and
	@var{align} must be positive absolute expressions. This directive
	differs from @samp{.lcomm} only in that it permits you to specify
	an alignment. @xref{Lcomm,,@code{.lcomm}}.
	@end table

	@table @code
	@cindex @code{extended} directive, i960
	@item .extended @var{flonums}
	@code{.extended} expects zero or more flonums, separated by commas; for
	each flonum, @samp{.extended} emits an @sc{ieee} extended-format (80-bit)
	floating-point number.

	@cindex @code{leafproc} directive, i960
	@item .leafproc @var{call-lab}, @var{bal-lab}
	You can use the @samp{.leafproc} directive in conjunction with the
	optimized @code{callj} instruction to enable faster calls of leaf
	procedures. If a procedure is known to call no other procedures, you
	may define an entry point that skips procedure prolog code (and that does
	not depend on system-supplied saved context), and declare it as the
	@var{bal-lab} using @samp{.leafproc}. If the procedure also has an
	entry point that goes through the normal prolog, you can specify that
	entry point as @var{call-lab}.

	A @samp{.leafproc} declaration is meant for use in conjunction with the
	optimized call instruction @samp{callj}; the directive records the data
	needed later to choose between converting the @samp{callj} into a
	@code{bal} or a @code{call}.

	@var{call-lab} is optional; if only one argument is present, or if the
	two arguments are identical, the single argument is assumed to be the
	@code{bal} entry point.

	@cindex @code{sysproc} directive, i960
	@item .sysproc @var{name}, @var{index}
	The @samp{.sysproc} directive defines a name for a system procedure.
	After you define it using @samp{.sysproc}, you can use @var{name} to
	refer to the system procedure identified by @var{index} when calling
	procedures with the optimized call instruction @samp{callj}.

	Both arguments are required; @var{index} must be between 0 and 31
	(inclusive).
	@end table

	@node Opcodes for i960
	@section i960 Opcodes

	@cindex opcodes, i960
	@cindex i960 opcodes
	All Intel 960 machine instructions are supported;
	@pxref{Options-i960,,i960 Command-line Options} for a discussion of
	selecting the instruction subset for a particular 960
	architecture.@refill

	Some opcodes are processed beyond simply emitting a single corresponding
	instruction: @samp{callj}, and Compare-and-Branch or Compare-and-Jump
	instructions with target displacements larger than 13 bits.

	@menu
	* callj-i960:: @code{callj}
	* Compare-and-branch-i960:: Compare-and-Branch
	@end menu

	@node callj-i960
	@subsection @code{callj}

	@cindex @code{callj}, i960 pseudo-opcode
	@cindex i960 @code{callj} pseudo-opcode
	You can write @code{callj} to have the assembler or the linker determine
	the most appropriate form of subroutine call: @samp{call},
	@samp{bal}, or @samp{calls}. If the assembly source contains
	enough information---a @samp{.leafproc} or @samp{.sysproc} directive
	defining the operand---then @code{@value{AS}} translates the
	@code{callj}; if not, it simply emits the @code{callj}, leaving it
	for the linker to resolve.

	@node Compare-and-branch-i960
	@subsection Compare-and-Branch

	@cindex i960 compare/branch instructions
	@cindex compare/branch instructions, i960
	The 960 architectures provide combined Compare-and-Branch instructions
	that permit you to store the branch target in the lower 13 bits of the
	instruction word itself. However, if you specify a branch target far
	enough away that its address won't fit in 13 bits, the assembler can
	either issue an error, or convert your Compare-and-Branch instruction
	into separate instructions to do the compare and the branch.

	@cindex compare and jump expansions, i960
	@cindex i960 compare and jump expansions
	Whether @code{@value{AS}} gives an error or expands the instruction depends
	on two choices you can make: whether you use the @samp{-no-relax} option,
	and whether you use a ``Compare and Branch'' instruction or a ``Compare
	and Jump'' instruction. The ``Jump'' instructions are @emph{always}
	expanded if necessary; the ``Branch'' instructions are expanded when
	necessary @emph{unless} you specify @code{-no-relax}---in which case
	@code{@value{AS}} gives an error instead.

	These are the Compare-and-Branch instructions, their ``Jump'' variants,
	and the instruction pairs they may expand into:

	@c TEXI2ROFF-KILL
	@ifinfo
	@c END TEXI2ROFF-KILL
	@example
	Compare and
	Branch Jump Expanded to
	------ ------ ------------
	bbc chkbit; bno
	bbs chkbit; bo
	cmpibe cmpije cmpi; be
	cmpibg cmpijg cmpi; bg
	cmpibge cmpijge cmpi; bge
	cmpibl cmpijl cmpi; bl
	cmpible cmpijle cmpi; ble
	cmpibno cmpijno cmpi; bno
	cmpibne cmpijne cmpi; bne
	cmpibo cmpijo cmpi; bo
	cmpobe cmpoje cmpo; be
	cmpobg cmpojg cmpo; bg
	cmpobge cmpojge cmpo; bge
	cmpobl cmpojl cmpo; bl
	cmpoble cmpojle cmpo; ble
	cmpobne cmpojne cmpo; bne
	@end example
	@c TEXI2ROFF-KILL
	@end ifinfo
	@tex
	\hskip\tableindent
	\halign{\hfil {\tt #}\quad&\hfil {\tt #}\qquad&{\tt #}\hfil\cr
	\omit{\hfil\it Compare and\hfil}\span\omit&\cr
	{\it Branch}&{\it Jump}&{\it Expanded to}\cr
	bbc& & chkbit; bno\cr
	bbs& & chkbit; bo\cr
	cmpibe& cmpije& cmpi; be\cr
	cmpibg& cmpijg& cmpi; bg\cr
	cmpibge& cmpijge& cmpi; bge\cr
	cmpibl& cmpijl& cmpi; bl\cr
	cmpible& cmpijle& cmpi; ble\cr
	cmpibno& cmpijno& cmpi; bno\cr
	cmpibne& cmpijne& cmpi; bne\cr
	cmpibo& cmpijo& cmpi; bo\cr
	cmpobe& cmpoje& cmpo; be\cr
	cmpobg& cmpojg& cmpo; bg\cr
	cmpobge& cmpojge& cmpo; bge\cr
	cmpobl& cmpojl& cmpo; bl\cr
	cmpoble& cmpojle& cmpo; ble\cr
	cmpobne& cmpojne& cmpo; bne\cr}
	@end tex
	@c END TEXI2ROFF-KILL

	@node Syntax of i960
	@section Syntax for the i960
	@menu
	* i960-Chars:: Special Characters
	@end menu

	@node i960-Chars
	@subsection Special Characters

	@cindex line comment character, i960
	@cindex i960 line comment character
	The presence of a @samp{#} on a line indicates the start of a comment
	that extends to the end of the current line.

	If a @samp{#} appears as the first character of a line, the whole line
	is treated as a comment, but in this case the line can also be a
	logical line number directive (@pxref{Comments}) or a
	preprocessor control command (@pxref{Preprocessing}).

	@cindex line separator, i960
	@cindex statement separator, i960
	@cindex i960 line separator
	The @samp{;} character can be used to separate statements on the same
	line.