1@c Copyright (C) 2008-2016 Free Software Foundation, Inc. 2@c This is part of the GAS manual. 3@c For copying conditions, see the file as.texinfo. 4@ifset GENERIC 5@page 6@node RX-Dependent 7@chapter RX Dependent Features 8@end ifset 9@ifclear GENERIC 10@node Machine Dependencies 11@chapter RX Dependent Features 12@end ifclear 13 14@cindex RX support 15@menu 16* RX-Opts:: RX Assembler Command Line Options 17* RX-Modifiers:: Symbolic Operand Modifiers 18* RX-Directives:: Assembler Directives 19* RX-Float:: Floating Point 20* RX-Syntax:: Syntax 21@end menu 22 23@node RX-Opts 24@section RX Options 25@cindex options, RX 26@cindex RX options 27 28The Renesas RX port of @code{@value{AS}} has a few target specfic 29command line options: 30 31@table @code 32 33@cindex @samp{-m32bit-doubles} 34@item -m32bit-doubles 35This option controls the ABI and indicates to use a 32-bit float ABI. 36It has no effect on the assembled instructions, but it does influence 37the behaviour of the @samp{.double} pseudo-op. 38This is the default. 39 40@cindex @samp{-m64bit-doubles} 41@item -m64bit-doubles 42This option controls the ABI and indicates to use a 64-bit float ABI. 43It has no effect on the assembled instructions, but it does influence 44the behaviour of the @samp{.double} pseudo-op. 45 46@cindex @samp{-mbig-endian} 47@item -mbig-endian 48This option controls the ABI and indicates to use a big-endian data 49ABI. It has no effect on the assembled instructions, but it does 50influence the behaviour of the @samp{.short}, @samp{.hword}, @samp{.int}, 51@samp{.word}, @samp{.long}, @samp{.quad} and @samp{.octa} pseudo-ops. 52 53@cindex @samp{-mlittle-endian} 54@item -mlittle-endian 55This option controls the ABI and indicates to use a little-endian data 56ABI. It has no effect on the assembled instructions, but it does 57influence the behaviour of the @samp{.short}, @samp{.hword}, @samp{.int}, 58@samp{.word}, @samp{.long}, @samp{.quad} and @samp{.octa} pseudo-ops. 59This is the default. 60 61@cindex @samp{-muse-conventional-section-names} 62@item -muse-conventional-section-names 63This option controls the default names given to the code (.text), 64initialised data (.data) and uninitialised data sections (.bss). 65 66@cindex @samp{-muse-renesas-section-names} 67@item -muse-renesas-section-names 68This option controls the default names given to the code (.P), 69initialised data (.D_1) and uninitialised data sections (.B_1). 70This is the default. 71 72@cindex @samp{-msmall-data-limit} 73@item -msmall-data-limit 74This option tells the assembler that the small data limit feature of 75the RX port of GCC is being used. This results in the assembler 76generating an undefined reference to a symbol called @code{__gp} for 77use by the relocations that are needed to support the small data limit 78feature. This option is not enabled by default as it would otherwise 79pollute the symbol table. 80 81@cindex @samp{-mpid} 82@item -mpid 83This option tells the assembler that the position independent data of the 84RX port of GCC is being used. This results in the assembler 85generating an undefined reference to a symbol called @code{__pid_base}, 86and also setting the RX_PID flag bit in the e_flags field of the ELF 87header of the object file. 88 89@cindex @samp{-mint-register} 90@item -mint-register=@var{num} 91This option tells the assembler how many registers have been reserved 92for use by interrupt handlers. This is needed in order to compute the 93correct values for the @code{%gpreg} and @code{%pidreg} meta registers. 94 95@cindex @samp{-mgcc-abi} 96@item -mgcc-abi 97This option tells the assembler that the old GCC ABI is being used by 98the assembled code. With this version of the ABI function arguments 99that are passed on the stack are aligned to a 32-bit boundary. 100 101@cindex @samp{-mrx-abi} 102@item -mrx-abi 103This option tells the assembler that the official RX ABI is being used 104by the assembled code. With this version of the ABI function 105arguments that are passed on the stack are aligned to their natural 106alignments. This option is the default. 107 108@cindex @samp{-mcpu=} 109@item -mcpu=@var{name} 110This option tells the assembler the target CPU type. Currently the 111@code{rx100}, @code{rx200}, @code{rx600}, @code{rx610} and @code{rxv2} 112are recognised as valid cpu names. Attempting to assemble an instruction 113not supported by the indicated cpu type will result in an error message 114being generated. 115 116@cindex @samp{-mno-allow-string-insns} 117@item -mno-allow-string-insns 118This option tells the assembler to mark the object file that it is 119building as one that does not use the string instructions 120@code{SMOVF}, @code{SCMPU}, @code{SMOVB}, @code{SMOVU}, @code{SUNTIL} 121@code{SWHILE} or the @code{RMPA} instruction. In addition the mark 122tells the linker to complain if an attempt is made to link the binary 123with another one that does use any of these instructions. 124 125Note - the inverse of this option, @code{-mallow-string-insns}, is 126not needed. The assembler automatically detects the use of the 127the instructions in the source code and labels the resulting 128object file appropriately. If no string instructions are detected 129then the object file is labelled as being one that can be linked with 130either string-using or string-banned object files. 131@end table 132 133@node RX-Modifiers 134@section Symbolic Operand Modifiers 135 136@cindex RX modifiers 137@cindex syntax, RX 138@cindex %gp 139 140The assembler supports one modifier when using symbol addresses 141in RX instruction operands. The general syntax is the following: 142 143@smallexample 144%gp(symbol) 145@end smallexample 146 147The modifier returns the offset from the @var{__gp} symbol to the 148specified symbol as a 16-bit value. The intent is that this offset 149should be used in a register+offset move instruction when generating 150references to small data. Ie, like this: 151 152@smallexample 153 mov.W %gp(_foo)[%gpreg], r1 154@end smallexample 155 156The assembler also supports two meta register names which can be used 157to refer to registers whose values may not be known to the 158programmer. These meta register names are: 159 160@table @code 161 162@cindex @samp{%gpreg} 163@item %gpreg 164The small data address register. 165 166@cindex @samp{%pidreg} 167@item %pidreg 168The PID base address register. 169 170@end table 171 172Both registers normally have the value r13, but this can change if 173some registers have been reserved for use by interrupt handlers or if 174both the small data limit and position independent data features are 175being used at the same time. 176 177@node RX-Directives 178@section Assembler Directives 179 180@cindex assembler directives, RX 181@cindex RX assembler directives 182 183The RX version of @code{@value{AS}} has the following specific 184assembler directives: 185 186@table @code 187 188@item .3byte 189@cindex assembler directive .3byte, RX 190@cindex RX assembler directive .3byte 191Inserts a 3-byte value into the output file at the current location. 192 193@item .fetchalign 194@cindex assembler directive .fetchalign, RX 195@cindex RX assembler directive .fetchalign 196If the next opcode following this directive spans a fetch line 197boundary (8 byte boundary), the opcode is aligned to that boundary. 198If the next opcode does not span a fetch line, this directive has no 199effect. Note that one or more labels may be between this directive 200and the opcode; those labels are aligned as well. Any inserted bytes 201due to alignment will form a NOP opcode. 202 203@end table 204 205@node RX-Float 206@section Floating Point 207 208@cindex floating point, RX 209@cindex RX floating point 210 211The floating point formats generated by directives are these. 212 213@table @code 214@cindex @code{float} directive, RX 215 216@item .float 217@code{Single} precision (32-bit) floating point constants. 218 219@cindex @code{double} directive, RX 220@item .double 221If the @option{-m64bit-doubles} command line option has been specified 222then then @code{double} directive generates @code{double} precision 223(64-bit) floating point constants, otherwise it generates 224@code{single} precision (32-bit) floating point constants. To force 225the generation of 64-bit floating point constants used the @code{dc.d} 226directive instead. 227 228@end table 229 230@node RX-Syntax 231@section Syntax for the RX 232@menu 233* RX-Chars:: Special Characters 234@end menu 235 236@node RX-Chars 237@subsection Special Characters 238 239@cindex line comment character, RX 240@cindex RX line comment character 241The presence of a @samp{;} appearing anywhere on a line indicates the 242start of a comment that extends to the end of that line. 243 244If a @samp{#} appears as the first character of a line then the whole 245line is treated as a comment, but in this case the line can also be a 246logical line number directive (@pxref{Comments}) or a preprocessor 247control command (@pxref{Preprocessing}). 248 249@cindex line separator, RX 250@cindex statement separator, RX 251@cindex RX line separator 252The @samp{!} character can be used to separate statements on the same 253line. 254