X-Git-Url: http://git.efficios.com/?a=blobdiff_plain;f=gas%2Fdoc%2Fc-mmix.texi;h=235aff21f9b754175a807320da730c8d9af6ba9e;hb=refs%2Fheads%2Fconcurrent-displaced-stepping-2020-04-01;hp=d1b3016f41aac68dfba82059551b7ca82ae039d5;hpb=062b7c0c141b6d28a037c6acf3a822539e701827;p=deliverable%2Fbinutils-gdb.git

diff --git a/gas/doc/c-mmix.texi b/gas/doc/c-mmix.texi
index d1b3016f41..235aff21f9 100644
--- a/gas/doc/c-mmix.texi
+++ b/gas/doc/c-mmix.texi
@@ -1,4 +1,4 @@
-@c Copyright 2001, 2002 Free Software Foundation, Inc.
+@c Copyright (C) 2001-2020 Free Software Foundation, Inc.
 @c This is part of the GAS manual.
 @c For copying conditions, see the file as.texinfo.
 @c MMIX description by Hans-Peter Nilsson, hp@bitrange.com
@@ -27,25 +27,25 @@
 @cindex MMIX options
 The MMIX version of @code{@value{AS}} has some machine-dependent options.
 
-@cindex @samp{--fixed-special-register-names} command line option, MMIX
+@cindex @samp{--fixed-special-register-names} command-line option, MMIX
 When @samp{--fixed-special-register-names} is specified, only the register
 names specified in @ref{MMIX-Regs} are recognized in the instructions
 @code{PUT} and @code{GET}.
 
-@cindex @samp{--globalize-symbols} command line option, MMIX
+@cindex @samp{--globalize-symbols} command-line option, MMIX
 You can use the @samp{--globalize-symbols} to make all symbols global.
 This option is useful when splitting up a @code{mmixal} program into
 several files.
 
-@cindex @samp{--gnu-syntax} command line option, MMIX
+@cindex @samp{--gnu-syntax} command-line option, MMIX
 The @samp{--gnu-syntax} turns off most syntax compatibility with
 @code{mmixal}.  Its usability is currently doubtful.
 
-@cindex @samp{--relax} command line option, MMIX
+@cindex @samp{--relax} command-line option, MMIX
 The @samp{--relax} option is not fully supported, but will eventually make
 the object file prepared for linker relaxation.
 
-@cindex @samp{--no-predefined-syms} command line option, MMIX
+@cindex @samp{--no-predefined-syms} command-line option, MMIX
 If you want to avoid inadvertently calling a predefined symbol and would
 rather get an error, for example when using @code{@value{AS}} with a
 compiler or other machine-generated code, specify
@@ -55,13 +55,13 @@ symbols, @samp{BIT} symbols, and @code{TRAP} symbols used in @code{mmix}
 ``system calls''.  It also turns off predefined special-register names,
 except when used in @code{PUT} and @code{GET} instructions.
 
-@cindex @samp{--no-expand} command line option, MMIX
+@cindex @samp{--no-expand} command-line option, MMIX
 By default, some instructions are expanded to fit the size of the operand
 or an external symbol (@pxref{MMIX-Expand}).  By passing
 @samp{--no-expand}, no such expansion will be done, instead causing errors
 at link time if the operand does not fit.
 
-@cindex @samp{--no-merge-gregs} command line option, MMIX
+@cindex @samp{--no-merge-gregs} command-line option, MMIX
 The @code{mmixal} documentation (@pxref{mmixsite}) specifies that global
 registers allocated with the @samp{GREG} directive (@pxref{MMIX-greg}) and
 initialized to the same non-zero value, will refer to the same global
@@ -70,7 +70,7 @@ final addresses aren't known until link-time, but it will do an effort
 unless the @samp{--no-merge-gregs} option is specified.  (Register merging
 isn't yet implemented in @code{@value{LD}}.)
 
-@cindex @samp{-x} command line option, MMIX
+@cindex @samp{-x} command-line option, MMIX
 @code{@value{AS}} will warn every time it expands an instruction to fit an
 operand unless the option @samp{-x} is specified.  It is believed that
 this behaviour is more useful than just mimicking @code{mmixal}'s
@@ -79,10 +79,25 @@ is specified, and assembly fails otherwise, when an instruction needs to
 be expanded.  It needs to be kept in mind that @code{mmixal} is both an
 assembler and linker, while @code{@value{AS}} will expand instructions
 that at link stage can be contracted.  (Though linker relaxation isn't yet
-implemented in @code{@value{LD}}.)  The option @samp{-x} also imples
+implemented in @code{@value{LD}}.)  The option @samp{-x} also implies
 @samp{--linker-allocated-gregs}.
 
-@cindex @samp{--linker-allocated-gregs} command line option, MMIX
+@cindex @samp{--no-pushj-stubs} command-line option, MMIX
+@cindex @samp{--no-stubs} command-line option, MMIX
+If instruction expansion is enabled, @code{@value{AS}} can expand a
+@samp{PUSHJ} instruction into a series of instructions.  The shortest
+expansion is to not expand it, but just mark the call as redirectable to a
+stub, which @code{@value{LD}} creates at link-time, but only if the
+original @samp{PUSHJ} instruction is found not to reach the target.  The
+stub consists of the necessary instructions to form a jump to the target.
+This happens if @code{@value{AS}} can assert that the @samp{PUSHJ}
+instruction can reach such a stub.  The option @samp{--no-pushj-stubs}
+disables this shorter expansion, and the longer series of instructions is
+then created at assembly-time.  The option @samp{--no-stubs} is a synonym,
+intended for compatibility with future releases, where generation of stubs
+for other instructions may be implemented.
+
+@cindex @samp{--linker-allocated-gregs} command-line option, MMIX
 Usually a two-operand-expression (@pxref{GREG-base}) without a matching
 @samp{GREG} directive is treated as an error by @code{@value{AS}}.  When
 the option @samp{--linker-allocated-gregs} is in effect, they are instead
@@ -157,7 +172,10 @@ specified, the rest of the line is ignored, treated as a comment.
 The characters @samp{*} and @samp{#} are line comment characters; each
 start a comment at the beginning of a line, but only at the beginning of a
 line.  A @samp{#} prefixes a hexadecimal number if found elsewhere on a
-line.
+line.  If a @samp{#} appears at the start of a line the whole line is
+treated as a comment, but the line can also act as a logical line
+number directive (@pxref{Comments}) or a preprocessor control command
+(@pxref{Preprocessing}).
 
 Two other characters, @samp{%} and @samp{!}, each start a comment anywhere
 on the line.  Thus you can't use the @samp{modulus} and @samp{not}
@@ -428,7 +446,7 @@ operand can be omitted, defaulting to a zero value.
 The directives @samp{WYDE}, @samp{TETRA} and @samp{OCTA} emit constants of
 two, four and eight bytes size respectively.  Before anything else happens
 for the directive, the current location is aligned to the respective
-constant-size bondary.  If a label is defined at the beginning of the
+constant-size boundary.  If a label is defined at the beginning of the
 line, its value will be that after the alignment.  A single operand can be
 omitted, defaulting to a zero value emitted for the directive.  Operands
 can be expressed as strings (@pxref{Strings}), in which case each
@@ -515,7 +533,7 @@ Operand syntax is a bit stricter with @code{@value{AS}} than
 must write @code{addu $1,$2,3}.
 
 You can't LOC to a lower address than those already visited
-(i.e. ``backwards'').
+(i.e., ``backwards'').
 
 A LOC directive must come before any emitted code.