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 28 The Renesas RX port of @code{@value{AS}} has a few target specfic 29 command line options: 30 31 @table @code 32 33 @cindex @samp{-m32bit-doubles} 34 @item -m32bit-doubles 35 This option controls the ABI and indicates to use a 32-bit float ABI. 36 It has no effect on the assembled instructions, but it does influence 37 the behaviour of the @samp{.double} pseudo-op. 38 This is the default. 39 40 @cindex @samp{-m64bit-doubles} 41 @item -m64bit-doubles 42 This option controls the ABI and indicates to use a 64-bit float ABI. 43 It has no effect on the assembled instructions, but it does influence 44 the behaviour of the @samp{.double} pseudo-op. 45 46 @cindex @samp{-mbig-endian} 47 @item -mbig-endian 48 This option controls the ABI and indicates to use a big-endian data 49 ABI. It has no effect on the assembled instructions, but it does 50 influence 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 55 This option controls the ABI and indicates to use a little-endian data 56 ABI. It has no effect on the assembled instructions, but it does 57 influence the behaviour of the @samp{.short}, @samp{.hword}, @samp{.int}, 58 @samp{.word}, @samp{.long}, @samp{.quad} and @samp{.octa} pseudo-ops. 59 This is the default. 60 61 @cindex @samp{-muse-conventional-section-names} 62 @item -muse-conventional-section-names 63 This option controls the default names given to the code (.text), 64 initialised data (.data) and uninitialised data sections (.bss). 65 66 @cindex @samp{-muse-renesas-section-names} 67 @item -muse-renesas-section-names 68 This option controls the default names given to the code (.P), 69 initialised data (.D_1) and uninitialised data sections (.B_1). 70 This is the default. 71 72 @cindex @samp{-msmall-data-limit} 73 @item -msmall-data-limit 74 This option tells the assembler that the small data limit feature of 75 the RX port of GCC is being used. This results in the assembler 76 generating an undefined reference to a symbol called @code{__gp} for 77 use by the relocations that are needed to support the small data limit 78 feature. This option is not enabled by default as it would otherwise 79 pollute the symbol table. 80 81 @cindex @samp{-mpid} 82 @item -mpid 83 This option tells the assembler that the position independent data of the 84 RX port of GCC is being used. This results in the assembler 85 generating an undefined reference to a symbol called @code{__pid_base}, 86 and also setting the RX_PID flag bit in the e_flags field of the ELF 87 header of the object file. 88 89 @cindex @samp{-mint-register} 90 @item -mint-register=@var{num} 91 This option tells the assembler how many registers have been reserved 92 for use by interrupt handlers. This is needed in order to compute the 93 correct values for the @code{%gpreg} and @code{%pidreg} meta registers. 94 95 @cindex @samp{-mgcc-abi} 96 @item -mgcc-abi 97 This option tells the assembler that the old GCC ABI is being used by 98 the assembled code. With this version of the ABI function arguments 99 that are passed on the stack are aligned to a 32-bit boundary. 100 101 @cindex @samp{-mrx-abi} 102 @item -mrx-abi 103 This option tells the assembler that the official RX ABI is being used 104 by the assembled code. With this version of the ABI function 105 arguments that are passed on the stack are aligned to their natural 106 alignments. This option is the default. 107 108 @cindex @samp{-mcpu=} 109 @item -mcpu=@var{name} 110 This option tells the assembler the target CPU type. Currently the 111 @code{rx100}, @code{rx200}, @code{rx600}, @code{rx610} and @code{rxv2} 112 are recognised as valid cpu names. Attempting to assemble an instruction 113 not supported by the indicated cpu type will result in an error message 114 being generated. 115 116 @cindex @samp{-mno-allow-string-insns} 117 @item -mno-allow-string-insns 118 This option tells the assembler to mark the object file that it is 119 building 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 122 tells the linker to complain if an attempt is made to link the binary 123 with another one that does use any of these instructions. 124 125 Note - the inverse of this option, @code{-mallow-string-insns}, is 126 not needed. The assembler automatically detects the use of the 127 the instructions in the source code and labels the resulting 128 object file appropriately. If no string instructions are detected 129 then the object file is labelled as being one that can be linked with 130 either 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 139 140 The assembler supports one modifier when using symbol addresses 141 in RX instruction operands. The general syntax is the following: 142 143 @smallexample 144 %gp(symbol) 145 @end smallexample 146 147 The modifier returns the offset from the @var{__gp} symbol to the 148 specified symbol as a 16-bit value. The intent is that this offset 149 should be used in a register+offset move instruction when generating 150 references to small data. Ie, like this: 151 152 @smallexample 153 mov.W %gp(_foo)[%gpreg], r1 154 @end smallexample 155 156 The assembler also supports two meta register names which can be used 157 to refer to registers whose values may not be known to the 158 programmer. These meta register names are: 159 160 @table @code 161 162 @cindex @samp{%gpreg} 163 @item %gpreg 164 The small data address register. 165 166 @cindex @samp{%pidreg} 167 @item %pidreg 168 The PID base address register. 169 170 @end table 171 172 Both registers normally have the value r13, but this can change if 173 some registers have been reserved for use by interrupt handlers or if 174 both the small data limit and position independent data features are 175 being 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 182 183 The RX version of @code{@value{AS}} has the following specific 184 assembler directives: 185 186 @table @code 187 188 @item .3byte 189 @cindex assembler directive .3byte, RX 190 @cindex RX assembler directive .3byte 191 Inserts 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 196 If the next opcode following this directive spans a fetch line 197 boundary (8 byte boundary), the opcode is aligned to that boundary. 198 If the next opcode does not span a fetch line, this directive has no 199 effect. Note that one or more labels may be between this directive 200 and the opcode; those labels are aligned as well. Any inserted bytes 201 due 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 210 211 The 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 221 If the @option{-m64bit-doubles} command line option has been specified 222 then 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 225 the generation of 64-bit floating point constants used the @code{dc.d} 226 directive 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 241 The presence of a @samp{;} appearing anywhere on a line indicates the 242 start of a comment that extends to the end of that line. 243 244 If a @samp{#} appears as the first character of a line then the whole 245 line is treated as a comment, but in this case the line can also be a 246 logical line number directive (@pxref{Comments}) or a preprocessor 247 control command (@pxref{Preprocessing}). 248 249 @cindex line separator, RX 250 @cindex statement separator, RX 251 @cindex RX line separator 252 The @samp{!} character can be used to separate statements on the same 253 line. 254
