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author | Roland Pesch <pesch@cygnus> | 1994-02-02 01:43:26 +0000 |
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committer | Roland Pesch <pesch@cygnus> | 1994-02-02 01:43:26 +0000 |
commit | 03d2167461ff56bd78f485ad5492769708e276f2 (patch) | |
tree | 58f07aa9960890311e720a2463cfbc21e3fb0d4e | |
parent | f2cdeec493b2b94f86cec07d250d6edf5a9243f9 (diff) | |
download | fsf-binutils-gdb-03d2167461ff56bd78f485ad5492769708e276f2.zip fsf-binutils-gdb-03d2167461ff56bd78f485ad5492769708e276f2.tar.gz fsf-binutils-gdb-03d2167461ff56bd78f485ad5492769708e276f2.tar.bz2 |
Better organization, indexing, for MIPS-dep section.
-rw-r--r-- | gas/doc/as.texinfo | 126 |
1 files changed, 94 insertions, 32 deletions
diff --git a/gas/doc/as.texinfo b/gas/doc/as.texinfo index 1cabef6..3eff58d 100644 --- a/gas/doc/as.texinfo +++ b/gas/doc/as.texinfo @@ -7112,48 +7112,110 @@ set addr(rd),imm4 subl rrd,addr(rs) @node Machine Dependencies @chapter MIPS Dependent Features @end ifclear -The MIPS @value{AS} supports the MIPS R2000 and R3000 processors. -It ignores the @samp{-nocpp} option. +@cindex MIPS R2000 +@cindex MIPS R3000 +@sc{gnu} @code{@value{AS}} for @sc{mips} architectures supports the @sc{mips} +@sc{r2000} and @sc{r3000} processors. For information about the @sc{mips} +instruction set, see @cite{MIPS RISC Architecture}, by Kane and Heindrich +(Prentice-Hall). -Not all traditional MIPS macro instructions are currently supported. -Specifically, @code{li.d} and @code{li.s} are not currently supported. +@menu +* MIPS Opts:: Assembler options +* MIPS Object:: ECOFF object code +* MIPS Stabs:: Directives for debugging information +* MIPS Missing:: Missing instructions +@end menu + +@node MIPS Opts +@section Assembler options + +The @sc{mips} configurations of @sc{gnu} @code{@value{AS}} support three +special options, and accept one other for command-line compatibility. -Assembling for a MIPS ECOFF target supports some additional sections +@table @code +@cindex @code{-G} option (MIPS) +@item -G @var{num} +This option sets the largest size of an object that can be referenced +implicitly with the @code{gp} register. It is only accepted for targets +that use @sc{ecoff} format. The default value is 8. + +@cindex @code{-EB} option (MIPS) +@cindex @code{-EL} option (MIPS) +@cindex MIPS big-endian output +@cindex MIPS little-endian output +@cindex big-endian output, MIPS +@cindex little-endian output, MIPS +@item -EB +@itemx -EL +Any @sc{mips} configuration of @code{@value{AS}} can select big-endian or +little-endian output at run time (unlike the other @sc{gnu} development +tools, which must be configured for one or the other). Use @samp{-EB} +to select big-endian output, and @samp{-EL} for little-endian. + +@cindex @code{-nocpp} ignored (MIPS) +@item -nocpp +This option is ignored. It is accepted for command-line compatibility with +other assemblers, which use it to turn off C style preprocessing. With +@sc{gnu} @code{@value{AS}}, there is no need for @samp{-nocpp}, because the +@sc{gnu} assembler itself never runs the C preprocessor. +@end table + +@node MIPS Object +@section MIPS ECOFF object code + +@cindex ECOFF sections +@cindex MIPS ECOFF sections +Assembling for a @sc{mips} @sc{ecoff} target supports some additional sections besides the usual @code{.text}, @code{.data} and @code{.bss}. The additional sections are @code{.rdata}, used for read-only data, @code{.sdata}, used for small data, and @code{.sbss}, used for small common objects. -When assembling for ECOFF, the assembler automatically uses the @code{$gp} -(@code{$28}) register when forming the address of a small object. Any object -in the @code{.sdata} or @code{.sbss} sections is considered ``small''. For -external objects or objects in the @code{.bss} section, you may use the -@samp{-G} option to control the size of objects for which the @code{$gp} -register is used; the default value is 8, meaning that a reference to any -object eight bytes or smaller uses @code{$gp}. Passing @samp{-G 0} to -@value{AS} prevents it from using the @code{$gp} register at all. The size of -an object in the @code{.bss} section is set by the @code{.comm} or -@code{.lcomm} directive that defines it. The size of an external object may be -set using the @code{.extern} directive. For example, @samp{.extern sym,4} -declares that the object at @code{sym} is 4 bytes in length, while leaving -@code{sym} otherwise undefined. - -Using small ECOFF objects requires linker support, and assumes that the -@code{$gp} register was initialized correctly (normally done automatically -by the startup code). MIPS ECOFF assembly code must avoid modifying the +@cindex small objects, MIPS ECOFF +@cindex @code{gp} register, MIPS +When assembling for @sc{ecoff}, the assembler uses the @code{$gp} (@code{$28}) +register to form the address of a ``small object''. Any object in the +@code{.sdata} or @code{.sbss} sections is considered ``small'' in this sense. +For external objects, or for objects in the @code{.bss} section, you can use +the @sc{gcc} @samp{-G} option to control the size of objects addressed via +@code{$gp}; the default value is 8, meaning that a reference to any object +eight bytes or smaller uses @code{$gp}. Passing @samp{-G 0} to +@code{@value{AS}} prevents it from using the @code{$gp} register on the basis +of object size (but the assembler uses @code{$gp} for objects in @code{.sdata} +or @code{sbss} in any case). The size of an object in the @code{.bss} section +is set by the @code{.comm} or @code{.lcomm} directive that defines it. The +size of an external object may be set with the @code{.extern} directive. For +example, @samp{.extern sym,4} declares that the object at @code{sym} is 4 bytes +in length, whie leaving @code{sym} otherwise undefined. + +Using small @sc{ecoff} objects requires linker support, and assumes that the +@code{$gp} register is correctly initialized (normally done automatically by +the startup code). @sc{mips} @sc{ecoff} assembly code must not modify the @code{$gp} register. -MIPS ECOFF @code{@value{AS}} supports several directives used for generating -debugging information which are not support by traditional MIPS -assemblers. These are @code{.def}, @code{.endef}, @code{.dim}, -@code{.file}, @code{.scl}, @code{.size}, @code{.tag}, @code{.type}, -@code{.val}, @code{.stabd}, @code{.stabn}, and @code{.stabs}. The -debugging information generated by the three @code{.stab} directives can -only be read by GDB, not by traditional MIPS debuggers (this enhancement -is required to fully support C++ debugging). These directives are -primarily used by compilers, not assembly language programmers, and are -described elsewhere in this manual. +@node MIPS Stabs +@section Directives for debugging information + +@cindex MIPS debugging directives +@sc{mips} @sc{ecoff} @code{@value{AS}} supports several directives used for +generating debugging information which are not support by traditional @sc{mips} +assemblers. These are @code{.def}, @code{.endef}, @code{.dim}, @code{.file}, +@code{.scl}, @code{.size}, @code{.tag}, @code{.type}, @code{.val}, +@code{.stabd}, @code{.stabn}, and @code{.stabs}. The debugging information +generated by the three @code{.stab} directives can only be read by @sc{gdb}, +not by traditional @sc{mips} debuggers (this enhancement is required to fully +support C++ debugging). These directives are primarily used by compilers, not +assembly language programmers! + +@node MIPS Missing +@section Missing instructions + +@cindex MIPS missing instructions +@cindex missing instructions, MIPS +Not all traditional @sc{mips} instructions are currently supported. +Specifically, @code{li.d} and @code{li.s} are not currently supported. + @end ifset @ifset GENERIC |