| @c Copyright (C) 2008-2016 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 RX-Dependent |
| @chapter RX Dependent Features |
| @end ifset |
| @ifclear GENERIC |
| @node Machine Dependencies |
| @chapter RX Dependent Features |
| @end ifclear |
| |
| @cindex RX support |
| @menu |
| * RX-Opts:: RX Assembler Command Line Options |
| * RX-Modifiers:: Symbolic Operand Modifiers |
| * RX-Directives:: Assembler Directives |
| * RX-Float:: Floating Point |
| * RX-Syntax:: Syntax |
| @end menu |
| |
| @node RX-Opts |
| @section RX Options |
| @cindex options, RX |
| @cindex RX options |
| |
| The Renesas RX port of @code{@value{AS}} has a few target specfic |
| command line options: |
| |
| @table @code |
| |
| @cindex @samp{-m32bit-doubles} |
| @item -m32bit-doubles |
| This option controls the ABI and indicates to use a 32-bit float ABI. |
| It has no effect on the assembled instructions, but it does influence |
| the behaviour of the @samp{.double} pseudo-op. |
| This is the default. |
| |
| @cindex @samp{-m64bit-doubles} |
| @item -m64bit-doubles |
| This option controls the ABI and indicates to use a 64-bit float ABI. |
| It has no effect on the assembled instructions, but it does influence |
| the behaviour of the @samp{.double} pseudo-op. |
| |
| @cindex @samp{-mbig-endian} |
| @item -mbig-endian |
| This option controls the ABI and indicates to use a big-endian data |
| ABI. It has no effect on the assembled instructions, but it does |
| influence the behaviour of the @samp{.short}, @samp{.hword}, @samp{.int}, |
| @samp{.word}, @samp{.long}, @samp{.quad} and @samp{.octa} pseudo-ops. |
| |
| @cindex @samp{-mlittle-endian} |
| @item -mlittle-endian |
| This option controls the ABI and indicates to use a little-endian data |
| ABI. It has no effect on the assembled instructions, but it does |
| influence the behaviour of the @samp{.short}, @samp{.hword}, @samp{.int}, |
| @samp{.word}, @samp{.long}, @samp{.quad} and @samp{.octa} pseudo-ops. |
| This is the default. |
| |
| @cindex @samp{-muse-conventional-section-names} |
| @item -muse-conventional-section-names |
| This option controls the default names given to the code (.text), |
| initialised data (.data) and uninitialised data sections (.bss). |
| |
| @cindex @samp{-muse-renesas-section-names} |
| @item -muse-renesas-section-names |
| This option controls the default names given to the code (.P), |
| initialised data (.D_1) and uninitialised data sections (.B_1). |
| This is the default. |
| |
| @cindex @samp{-msmall-data-limit} |
| @item -msmall-data-limit |
| This option tells the assembler that the small data limit feature of |
| the RX port of GCC is being used. This results in the assembler |
| generating an undefined reference to a symbol called @code{__gp} for |
| use by the relocations that are needed to support the small data limit |
| feature. This option is not enabled by default as it would otherwise |
| pollute the symbol table. |
| |
| @cindex @samp{-mpid} |
| @item -mpid |
| This option tells the assembler that the position independent data of the |
| RX port of GCC is being used. This results in the assembler |
| generating an undefined reference to a symbol called @code{__pid_base}, |
| and also setting the RX_PID flag bit in the e_flags field of the ELF |
| header of the object file. |
| |
| @cindex @samp{-mint-register} |
| @item -mint-register=@var{num} |
| This option tells the assembler how many registers have been reserved |
| for use by interrupt handlers. This is needed in order to compute the |
| correct values for the @code{%gpreg} and @code{%pidreg} meta registers. |
| |
| @cindex @samp{-mgcc-abi} |
| @item -mgcc-abi |
| This option tells the assembler that the old GCC ABI is being used by |
| the assembled code. With this version of the ABI function arguments |
| that are passed on the stack are aligned to a 32-bit boundary. |
| |
| @cindex @samp{-mrx-abi} |
| @item -mrx-abi |
| This option tells the assembler that the official RX ABI is being used |
| by the assembled code. With this version of the ABI function |
| arguments that are passed on the stack are aligned to their natural |
| alignments. This option is the default. |
| |
| @cindex @samp{-mcpu=} |
| @item -mcpu=@var{name} |
| This option tells the assembler the target CPU type. Currently the |
| @code{rx100}, @code{rx200}, @code{rx600}, @code{rx610} and @code{rxv2} |
| are recognised as valid cpu names. Attempting to assemble an instruction |
| not supported by the indicated cpu type will result in an error message |
| being generated. |
| |
| @cindex @samp{-mno-allow-string-insns} |
| @item -mno-allow-string-insns |
| This option tells the assembler to mark the object file that it is |
| building as one that does not use the string instructions |
| @code{SMOVF}, @code{SCMPU}, @code{SMOVB}, @code{SMOVU}, @code{SUNTIL} |
| @code{SWHILE} or the @code{RMPA} instruction. In addition the mark |
| tells the linker to complain if an attempt is made to link the binary |
| with another one that does use any of these instructions. |
| |
| Note - the inverse of this option, @code{-mallow-string-insns}, is |
| not needed. The assembler automatically detects the use of the |
| the instructions in the source code and labels the resulting |
| object file appropriately. If no string instructions are detected |
| then the object file is labelled as being one that can be linked with |
| either string-using or string-banned object files. |
| @end table |
| |
| @node RX-Modifiers |
| @section Symbolic Operand Modifiers |
| |
| @cindex RX modifiers |
| @cindex syntax, RX |
| @cindex %gp |
| |
| The assembler supports one modifier when using symbol addresses |
| in RX instruction operands. The general syntax is the following: |
| |
| @smallexample |
| %gp(symbol) |
| @end smallexample |
| |
| The modifier returns the offset from the @var{__gp} symbol to the |
| specified symbol as a 16-bit value. The intent is that this offset |
| should be used in a register+offset move instruction when generating |
| references to small data. Ie, like this: |
| |
| @smallexample |
| mov.W %gp(_foo)[%gpreg], r1 |
| @end smallexample |
| |
| The assembler also supports two meta register names which can be used |
| to refer to registers whose values may not be known to the |
| programmer. These meta register names are: |
| |
| @table @code |
| |
| @cindex @samp{%gpreg} |
| @item %gpreg |
| The small data address register. |
| |
| @cindex @samp{%pidreg} |
| @item %pidreg |
| The PID base address register. |
| |
| @end table |
| |
| Both registers normally have the value r13, but this can change if |
| some registers have been reserved for use by interrupt handlers or if |
| both the small data limit and position independent data features are |
| being used at the same time. |
| |
| @node RX-Directives |
| @section Assembler Directives |
| |
| @cindex assembler directives, RX |
| @cindex RX assembler directives |
| |
| The RX version of @code{@value{AS}} has the following specific |
| assembler directives: |
| |
| @table @code |
| |
| @item .3byte |
| @cindex assembler directive .3byte, RX |
| @cindex RX assembler directive .3byte |
| Inserts a 3-byte value into the output file at the current location. |
| |
| @item .fetchalign |
| @cindex assembler directive .fetchalign, RX |
| @cindex RX assembler directive .fetchalign |
| If the next opcode following this directive spans a fetch line |
| boundary (8 byte boundary), the opcode is aligned to that boundary. |
| If the next opcode does not span a fetch line, this directive has no |
| effect. Note that one or more labels may be between this directive |
| and the opcode; those labels are aligned as well. Any inserted bytes |
| due to alignment will form a NOP opcode. |
| |
| @end table |
| |
| @node RX-Float |
| @section Floating Point |
| |
| @cindex floating point, RX |
| @cindex RX floating point |
| |
| The floating point formats generated by directives are these. |
| |
| @table @code |
| @cindex @code{float} directive, RX |
| |
| @item .float |
| @code{Single} precision (32-bit) floating point constants. |
| |
| @cindex @code{double} directive, RX |
| @item .double |
| If the @option{-m64bit-doubles} command line option has been specified |
| then then @code{double} directive generates @code{double} precision |
| (64-bit) floating point constants, otherwise it generates |
| @code{single} precision (32-bit) floating point constants. To force |
| the generation of 64-bit floating point constants used the @code{dc.d} |
| directive instead. |
| |
| @end table |
| |
| @node RX-Syntax |
| @section Syntax for the RX |
| @menu |
| * RX-Chars:: Special Characters |
| @end menu |
| |
| @node RX-Chars |
| @subsection Special Characters |
| |
| @cindex line comment character, RX |
| @cindex RX line comment character |
| The presence of a @samp{;} appearing anywhere on a line indicates the |
| start of a comment that extends to the end of that line. |
| |
| If a @samp{#} appears as the first character of a line then 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, RX |
| @cindex statement separator, RX |
| @cindex RX line separator |
| The @samp{!} character can be used to separate statements on the same |
| line. |