1@c Copyright 2000, 2002, 2003 Free Software Foundation, Inc. 2@c This is part of the GAS manual. 3@c For copying conditions, see the file as.texinfo. 4@c TI TMS320C54X description by Timothy Wall, twall@cygnus.com 5@ifset GENERIC 6@page 7@node TIC54X-Dependent 8@chapter TIC54X Dependent Features 9@end ifset 10@ifclear GENERIC 11@node Machine Dependencies 12@chapter TIC54X Dependent Features 13@end ifclear 14 15@cindex TIC54X support 16@menu 17* TIC54X-Opts:: Command-line Options 18* TIC54X-Block:: Blocking 19* TIC54X-Env:: Environment Settings 20* TIC54X-Constants:: Constants Syntax 21* TIC54X-Subsyms:: String Substitution 22* TIC54X-Locals:: Local Label Syntax 23* TIC54X-Builtins:: Builtin Assembler Math Functions 24* TIC54X-Ext:: Extended Addressing Support 25* TIC54X-Directives:: Directives 26* TIC54X-Macros:: Macro Features 27* TIC54X-MMRegs:: Memory-mapped Registers 28@end menu 29 30@node TIC54X-Opts 31@section Options 32 33@cindex options, TIC54X 34@cindex TIC54X options 35The TMS320C54x version of @code{@value{AS}} has a few machine-dependent options. 36 37@cindex @samp{-mfar-mode} option, far-mode 38@cindex @samp{-mf} option, far-mode 39You can use the @samp{-mfar-mode} option to enable extended addressing mode. 40All addresses will be assumed to be > 16 bits, and the appropriate 41relocation types will be used. This option is equivalent to using the 42@samp{.far_mode} directive in the assembly code. If you do not use the 43@samp{-mfar-mode} option, all references will be assumed to be 16 bits. 44This option may be abbreviated to @samp{-mf}. 45 46@cindex @samp{-mcpu} option, cpu 47You can use the @samp{-mcpu} option to specify a particular CPU. 48This option is equivalent to using the @samp{.version} directive in the 49assembly code. For recognized CPU codes, see 50@xref{TIC54X-Directives,,@code{.version}}. The default CPU version is 51@samp{542}. 52 53@cindex @samp{-merrors-to-file} option, stderr redirect 54@cindex @samp{-me} option, stderr redirect 55You can use the @samp{-merrors-to-file} option to redirect error output 56to a file (this provided for those deficient environments which don't 57provide adequate output redirection). This option may be abbreviated to 58@samp{-me}. 59 60@node TIC54X-Block 61@section Blocking 62A blocked section or memory block is guaranteed not to cross the blocking 63boundary (usually a page, or 128 words) if it is smaller than the 64blocking size, or to start on a page boundary if it is larger than the 65blocking size. 66 67@node TIC54X-Env 68@section Environment Settings 69 70@cindex environment settings, TIC54X 71@cindex @samp{A_DIR} environment variable, TIC54X 72@cindex @samp{C54XDSP_DIR} environment variable, TIC54X 73@samp{C54XDSP_DIR} and @samp{A_DIR} are semicolon-separated 74paths which are added to the list of directories normally searched for 75source and include files. @samp{C54XDSP_DIR} will override @samp{A_DIR}. 76 77@node TIC54X-Constants 78@section Constants Syntax 79 80@cindex constants, TIC54X 81The TIC54X version of @code{@value{AS}} allows the following additional 82constant formats, using a suffix to indicate the radix: 83@smallexample 84@cindex binary constants, TIC54X 85 86Binary @code{000000B, 011000b} 87Octal @code{10Q, 224q} 88Hexadecimal @code{45h, 0FH} 89 90@end smallexample 91 92@node TIC54X-Subsyms 93@section String Substitution 94A subset of allowable symbols (which we'll call subsyms) may be assigned 95arbitrary string values. This is roughly equivalent to C preprocessor 96#define macros. When @code{@value{AS}} encounters one of these 97symbols, the symbol is replaced in the input stream by its string value. 98Subsym names @strong{must} begin with a letter. 99 100Subsyms may be defined using the @code{.asg} and @code{.eval} directives 101(@xref{TIC54X-Directives,,@code{.asg}}, 102@xref{TIC54X-Directives,,@code{.eval}}. 103 104Expansion is recursive until a previously encountered symbol is seen, at 105which point substitution stops. 106 107In this example, x is replaced with SYM2; SYM2 is replaced with SYM1, and SYM1 108is replaced with x. At this point, x has already been encountered 109and the substitution stops. 110 111@smallexample @code 112 .asg "x",SYM1 113 .asg "SYM1",SYM2 114 .asg "SYM2",x 115 add x,a ; final code assembled is "add x, a" 116@end smallexample 117 118Macro parameters are converted to subsyms; a side effect of this is the normal 119@code{@value{AS}} '\ARG' dereferencing syntax is unnecessary. Subsyms 120defined within a macro will have global scope, unless the @code{.var} 121directive is used to identify the subsym as a local macro variable 122@pxref{TIC54X-Directives,,@code{.var}}. 123 124Substitution may be forced in situations where replacement might be 125ambiguous by placing colons on either side of the subsym. The following 126code: 127 128@smallexample @code 129 .eval "10",x 130LAB:X: add #x, a 131@end smallexample 132 133When assembled becomes: 134 135@smallexample @code 136LAB10 add #10, a 137@end smallexample 138 139Smaller parts of the string assigned to a subsym may be accessed with 140the following syntax: 141 142@table @code 143@item @code{:@var{symbol}(@var{char_index}):} 144Evaluates to a single-character string, the character at @var{char_index}. 145@item @code{:@var{symbol}(@var{start},@var{length}):} 146Evaluates to a substring of @var{symbol} beginning at @var{start} with 147length @var{length}. 148@end table 149 150@node TIC54X-Locals 151@section Local Labels 152Local labels may be defined in two ways: 153 154@itemize @bullet 155@item 156$N, where N is a decimal number between 0 and 9 157@item 158LABEL?, where LABEL is any legal symbol name. 159@end itemize 160 161Local labels thus defined may be redefined or automatically generated. 162The scope of a local label is based on when it may be undefined or reset. 163This happens when one of the following situations is encountered: 164 165@itemize @bullet 166@item 167.newblock directive @pxref{TIC54X-Directives,,@code{.newblock}} 168@item 169The current section is changed (.sect, .text, or .data) 170@item 171Entering or leaving an included file 172@item 173The macro scope where the label was defined is exited 174@end itemize 175 176@node TIC54X-Builtins 177@section Math Builtins 178 179@cindex math builtins, TIC54X 180@cindex TIC54X builtin math functions 181@cindex builtin math functions, TIC54X 182 183The following built-in functions may be used to generate a 184floating-point value. All return a floating-point value except 185@samp{$cvi}, @samp{$int}, and @samp{$sgn}, which return an integer 186value. 187 188@table @code 189@cindex @code{$acos} math builtin, TIC54X 190@item @code{$acos(@var{expr})} 191Returns the floating point arccosine of @var{expr}. 192 193@cindex @code{$asin} math builtin, TIC54X 194@item @code{$asin(@var{expr})} 195Returns the floating point arcsine of @var{expr}. 196 197@cindex @code{$atan} math builtin, TIC54X 198@item @code{$atan(@var{expr})} 199Returns the floating point arctangent of @var{expr}. 200 201@cindex @code{$atan2} math builtin, TIC54X 202@item @code{$atan2(@var{expr1},@var{expr2})} 203Returns the floating point arctangent of @var{expr1} / @var{expr2}. 204 205@cindex @code{$ceil} math builtin, TIC54X 206@item @code{$ceil(@var{expr})} 207Returns the smallest integer not less than @var{expr} as floating point. 208 209@cindex @code{$cosh} math builtin, TIC54X 210@item @code{$cosh(@var{expr})} 211Returns the floating point hyperbolic cosine of @var{expr}. 212 213@cindex @code{$cos} math builtin, TIC54X 214@item @code{$cos(@var{expr})} 215Returns the floating point cosine of @var{expr}. 216 217@cindex @code{$cvf} math builtin, TIC54X 218@item @code{$cvf(@var{expr})} 219Returns the integer value @var{expr} converted to floating-point. 220 221@cindex @code{$cvi} math builtin, TIC54X 222@item @code{$cvi(@var{expr})} 223Returns the floating point value @var{expr} converted to integer. 224 225@cindex @code{$exp} math builtin, TIC54X 226@item @code{$exp(@var{expr})} 227Returns the floating point value e ^ @var{expr}. 228 229@cindex @code{$fabs} math builtin, TIC54X 230@item @code{$fabs(@var{expr})} 231Returns the floating point absolute value of @var{expr}. 232 233@cindex @code{$floor} math builtin, TIC54X 234@item @code{$floor(@var{expr})} 235Returns the largest integer that is not greater than @var{expr} as 236floating point. 237 238@cindex @code{$fmod} math builtin, TIC54X 239@item @code{$fmod(@var{expr1},@var{expr2})} 240Returns the floating point remainder of @var{expr1} / @var{expr2}. 241 242@cindex @code{$int} math builtin, TIC54X 243@item @code{$int(@var{expr})} 244Returns 1 if @var{expr} evaluates to an integer, zero otherwise. 245 246@cindex @code{$ldexp} math builtin, TIC54X 247@item @code{$ldexp(@var{expr1},@var{expr2})} 248Returns the floating point value @var{expr1} * 2 ^ @var{expr2}. 249 250@cindex @code{$log10} math builtin, TIC54X 251@item @code{$log10(@var{expr})} 252Returns the base 10 logarithm of @var{expr}. 253 254@cindex @code{$log} math builtin, TIC54X 255@item @code{$log(@var{expr})} 256Returns the natural logarithm of @var{expr}. 257 258@cindex @code{$max} math builtin, TIC54X 259@item @code{$max(@var{expr1},@var{expr2})} 260Returns the floating point maximum of @var{expr1} and @var{expr2}. 261 262@cindex @code{$min} math builtin, TIC54X 263@item @code{$min(@var{expr1},@var{expr2})} 264Returns the floating point minimum of @var{expr1} and @var{expr2}. 265 266@cindex @code{$pow} math builtin, TIC54X 267@item @code{$pow(@var{expr1},@var{expr2})} 268Returns the floating point value @var{expr1} ^ @var{expr2}. 269 270@cindex @code{$round} math builtin, TIC54X 271@item @code{$round(@var{expr})} 272Returns the nearest integer to @var{expr} as a floating point number. 273 274@cindex @code{$sgn} math builtin, TIC54X 275@item @code{$sgn(@var{expr})} 276Returns -1, 0, or 1 based on the sign of @var{expr}. 277 278@cindex @code{$sin} math builtin, TIC54X 279@item @code{$sin(@var{expr})} 280Returns the floating point sine of @var{expr}. 281 282@cindex @code{$sinh} math builtin, TIC54X 283@item @code{$sinh(@var{expr})} 284Returns the floating point hyperbolic sine of @var{expr}. 285 286@cindex @code{$sqrt} math builtin, TIC54X 287@item @code{$sqrt(@var{expr})} 288Returns the floating point square root of @var{expr}. 289 290@cindex @code{$tan} math builtin, TIC54X 291@item @code{$tan(@var{expr})} 292Returns the floating point tangent of @var{expr}. 293 294@cindex @code{$tanh} math builtin, TIC54X 295@item @code{$tanh(@var{expr})} 296Returns the floating point hyperbolic tangent of @var{expr}. 297 298@cindex @code{$trunc} math builtin, TIC54X 299@item @code{$trunc(@var{expr})} 300Returns the integer value of @var{expr} truncated towards zero as 301floating point. 302 303@end table 304 305@node TIC54X-Ext 306@section Extended Addressing 307The @code{LDX} pseudo-op is provided for loading the extended addressing bits 308of a label or address. For example, if an address @code{_label} resides 309in extended program memory, the value of @code{_label} may be loaded as 310follows: 311@smallexample @code 312 ldx #_label,16,a ; loads extended bits of _label 313 or #_label,a ; loads lower 16 bits of _label 314 bacc a ; full address is in accumulator A 315@end smallexample 316 317@node TIC54X-Directives 318@section Directives 319 320@cindex machine directives, TIC54X 321@cindex TIC54X machine directives 322 323@table @code 324 325@cindex @code{align} directive, TIC54X 326@cindex @code{even} directive, TIC54X 327@item .align [@var{size}] 328@itemx .even 329Align the section program counter on the next boundary, based on 330@var{size}. @var{size} may be any power of 2. @code{.even} is 331equivalent to @code{.align} with a @var{size} of 2. 332@table @code 333@item 1 334Align SPC to word boundary 335@item 2 336Align SPC to longword boundary (same as .even) 337@item 128 338Align SPC to page boundary 339@end table 340 341@cindex @code{asg} directive, TIC54X 342@item .asg @var{string}, @var{name} 343Assign @var{name} the string @var{string}. String replacement is 344performed on @var{string} before assignment. 345 346@cindex @code{eval} directive, TIC54X 347@itemx .eval @var{string}, @var{name} 348Evaluate the contents of string @var{string} and assign the result as a 349string to the subsym @var{name}. String replacement is performed on 350@var{string} before assignment. 351 352@cindex @code{bss} directive, TIC54X 353@item .bss @var{symbol}, @var{size} [, [@var{blocking_flag}] [,@var{alignment_flag}]] 354Reserve space for @var{symbol} in the .bss section. @var{size} is in 355words. If present, @var{blocking_flag} indicates the allocated space 356should be aligned on a page boundary if it would otherwise cross a page 357boundary. If present, @var{alignment_flag} causes the assembler to 358allocate @var{size} on a long word boundary. 359 360@cindex @code{byte} directive, TIC54X 361@cindex @code{ubyte} directive, TIC54X 362@cindex @code{char} directive, TIC54X 363@cindex @code{uchar} directive, TIC54X 364@item .byte @var{value} [,...,@var{value_n}] 365@itemx .ubyte @var{value} [,...,@var{value_n}] 366@itemx .char @var{value} [,...,@var{value_n}] 367@itemx .uchar @var{value} [,...,@var{value_n}] 368Place one or more bytes into consecutive words of the current section. 369The upper 8 bits of each word is zero-filled. If a label is used, it 370points to the word allocated for the first byte encountered. 371 372@cindex @code{clink} directive, TIC54X 373@item .clink ["@var{section_name}"] 374Set STYP_CLINK flag for this section, which indicates to the linker that 375if no symbols from this section are referenced, the section should not 376be included in the link. If @var{section_name} is omitted, the current 377section is used. 378 379@cindex @code{c_mode} directive, TIC54X 380@item .c_mode 381TBD. 382 383@cindex @code{copy} directive, TIC54X 384@item .copy "@var{filename}" | @var{filename} 385@itemx .include "@var{filename}" | @var{filename} 386Read source statements from @var{filename}. The normal include search 387path is used. Normally .copy will cause statements from the included 388file to be printed in the assembly listing and .include will not, but 389this distinction is not currently implemented. 390 391@cindex @code{data} directive, TIC54X 392@item .data 393Begin assembling code into the .data section. 394 395@cindex @code{double} directive, TIC54X 396@cindex @code{ldouble} directive, TIC54X 397@cindex @code{float} directive, TIC54X 398@cindex @code{xfloat} directive, TIC54X 399@item .double @var{value} [,...,@var{value_n}] 400@itemx .ldouble @var{value} [,...,@var{value_n}] 401@itemx .float @var{value} [,...,@var{value_n}] 402@itemx .xfloat @var{value} [,...,@var{value_n}] 403Place an IEEE single-precision floating-point representation of one or 404more floating-point values into the current section. All but 405@code{.xfloat} align the result on a longword boundary. Values are 406stored most-significant word first. 407 408@cindex @code{drlist} directive, TIC54X 409@cindex @code{drnolist} directive, TIC54X 410@item .drlist 411@itemx .drnolist 412Control printing of directives to the listing file. Ignored. 413 414@cindex @code{emsg} directive, TIC54X 415@cindex @code{mmsg} directive, TIC54X 416@cindex @code{wmsg} directive, TIC54X 417@item .emsg @var{string} 418@itemx .mmsg @var{string} 419@itemx .wmsg @var{string} 420Emit a user-defined error, message, or warning, respectively. 421 422@cindex @code{far_mode} directive, TIC54X 423@item .far_mode 424Use extended addressing when assembling statements. This should appear 425only once per file, and is equivalent to the -mfar-mode option @pxref{TIC54X-Opts,,@code{-mfar-mode}}. 426 427@cindex @code{fclist} directive, TIC54X 428@cindex @code{fcnolist} directive, TIC54X 429@item .fclist 430@itemx .fcnolist 431Control printing of false conditional blocks to the listing file. 432 433@cindex @code{field} directive, TIC54X 434@item .field @var{value} [,@var{size}] 435Initialize a bitfield of @var{size} bits in the current section. If 436@var{value} is relocatable, then @var{size} must be 16. @var{size} 437defaults to 16 bits. If @var{value} does not fit into @var{size} bits, 438the value will be truncated. Successive @code{.field} directives will 439pack starting at the current word, filling the most significant bits 440first, and aligning to the start of the next word if the field size does 441not fit into the space remaining in the current word. A @code{.align} 442directive with an operand of 1 will force the next @code{.field} 443directive to begin packing into a new word. If a label is used, it 444points to the word that contains the specified field. 445 446@cindex @code{global} directive, TIC54X 447@cindex @code{def} directive, TIC54X 448@cindex @code{ref} directive, TIC54X 449@item .global @var{symbol} [,...,@var{symbol_n}] 450@itemx .def @var{symbol} [,...,@var{symbol_n}] 451@itemx .ref @var{symbol} [,...,@var{symbol_n}] 452@code{.def} nominally identifies a symbol defined in the current file 453and availalbe to other files. @code{.ref} identifies a symbol used in 454the current file but defined elsewhere. Both map to the standard 455@code{.global} directive. 456 457@cindex @code{half} directive, TIC54X 458@cindex @code{uhalf} directive, TIC54X 459@cindex @code{short} directive, TIC54X 460@cindex @code{ushort} directive, TIC54X 461@cindex @code{int} directive, TIC54X 462@cindex @code{uint} directive, TIC54X 463@cindex @code{word} directive, TIC54X 464@cindex @code{uword} directive, TIC54X 465@item .half @var{value} [,...,@var{value_n}] 466@itemx .uhalf @var{value} [,...,@var{value_n}] 467@itemx .short @var{value} [,...,@var{value_n}] 468@itemx .ushort @var{value} [,...,@var{value_n}] 469@itemx .int @var{value} [,...,@var{value_n}] 470@itemx .uint @var{value} [,...,@var{value_n}] 471@itemx .word @var{value} [,...,@var{value_n}] 472@itemx .uword @var{value} [,...,@var{value_n}] 473Place one or more values into consecutive words of the current section. 474If a label is used, it points to the word allocated for the first value 475encountered. 476 477@cindex @code{label} directive, TIC54X 478@item .label @var{symbol} 479Define a special @var{symbol} to refer to the load time address of the 480current section program counter. 481 482@cindex @code{length} directive, TIC54X 483@cindex @code{width} directive, TIC54X 484@item .length 485@itemx .width 486Set the page length and width of the output listing file. Ignored. 487 488@cindex @code{list} directive, TIC54X 489@cindex @code{nolist} directive, TIC54X 490@item .list 491@itemx .nolist 492Control whether the source listing is printed. Ignored. 493 494@cindex @code{long} directive, TIC54X 495@cindex @code{ulong} directive, TIC54X 496@cindex @code{xlong} directive, TIC54X 497@item .long @var{value} [,...,@var{value_n}] 498@itemx .ulong @var{value} [,...,@var{value_n}] 499@itemx .xlong @var{value} [,...,@var{value_n}] 500Place one or more 32-bit values into consecutive words in the current 501section. The most significant word is stored first. @code{.long} and 502@code{.ulong} align the result on a longword boundary; @code{xlong} does 503not. 504 505@cindex @code{loop} directive, TIC54X 506@cindex @code{break} directive, TIC54X 507@cindex @code{endloop} directive, TIC54X 508@item .loop [@var{count}] 509@itemx .break [@var{condition}] 510@itemx .endloop 511Repeatedly assemble a block of code. @code{.loop} begins the block, and 512@code{.endloop} marks its termination. @var{count} defaults to 1024, 513and indicates the number of times the block should be repeated. 514@code{.break} terminates the loop so that assembly begins after the 515@code{.endloop} directive. The optional @var{condition} will cause the 516loop to terminate only if it evaluates to zero. 517 518@cindex @code{macro} directive, TIC54X 519@cindex @code{endm} directive, TIC54X 520@item @var{macro_name} .macro [@var{param1}][,...@var{param_n}] 521@itemx [.mexit] 522@itemx .endm 523See the section on macros for more explanation (@xref{TIC54X-Macros}. 524 525@cindex @code{mlib} directive, TIC54X 526@item .mlib "@var{filename}" | @var{filename} 527Load the macro library @var{filename}. @var{filename} must be an 528archived library (BFD ar-compatible) of text files, expected to contain 529only macro definitions. The standard include search path is used. 530 531@cindex @code{mlist} directive, TIC54X 532@cindex @code{mnolist} directive, TIC54X 533@item .mlist 534@item .mnolist 535Control whether to include macro and loop block expansions in the 536listing output. Ignored. 537 538@cindex @code{mmregs} directive, TIC54X 539@item .mmregs 540Define global symbolic names for the 'c54x registers. Supposedly 541equivalent to executing @code{.set} directives for each register with 542its memory-mapped value, but in reality is provided only for 543compatibility and does nothing. 544 545@cindex @code{newblock} directive, TIC54X 546@item .newblock 547This directive resets any TIC54X local labels currently defined. Normal 548@code{@value{AS}} local labels are unaffected. 549 550@cindex @code{option} directive, TIC54X 551@item .option @var{option_list} 552Set listing options. Ignored. 553 554@cindex @code{sblock} directive, TIC54X 555@item .sblock "@var{section_name}" | @var{section_name} [,"@var{name_n}" | @var{name_n}] 556Designate @var{section_name} for blocking. Blocking guarantees that a 557section will start on a page boundary (128 words) if it would otherwise 558cross a page boundary. Only initialized sections may be designated with 559this directive. See also @xref{TIC54X-Block}. 560 561@cindex @code{sect} directive, TIC54X 562@item .sect "@var{section_name}" 563Define a named initialized section and make it the current section. 564 565@cindex @code{set} directive, TIC54X 566@cindex @code{equ} directive, TIC54X 567@item @var{symbol} .set "@var{value}" 568@itemx @var{symbol} .equ "@var{value}" 569Equate a constant @var{value} to a @var{symbol}, which is placed in the 570symbol table. @var{symbol} may not be previously defined. 571 572@cindex @code{space} directive, TIC54X 573@cindex @code{bes} directive, TIC54X 574@item .space @var{size_in_bits} 575@itemx .bes @var{size_in_bits} 576Reserve the given number of bits in the current section and zero-fill 577them. If a label is used with @code{.space}, it points to the 578@strong{first} word reserved. With @code{.bes}, the label points to the 579@strong{last} word reserved. 580 581@cindex @code{sslist} directive, TIC54X 582@cindex @code{ssnolist} directive, TIC54X 583@item .sslist 584@itemx .ssnolist 585Controls the inclusion of subsym replacement in the listing output. Ignored. 586 587@cindex @code{string} directive, TIC54X 588@cindex @code{pstring} directive, TIC54X 589@item .string "@var{string}" [,...,"@var{string_n}"] 590@itemx .pstring "@var{string}" [,...,"@var{string_n}"] 591Place 8-bit characters from @var{string} into the current section. 592@code{.string} zero-fills the upper 8 bits of each word, while 593@code{.pstring} puts two characters into each word, filling the 594most-significant bits first. Unused space is zero-filled. If a label 595is used, it points to the first word initialized. 596 597@cindex @code{struct} directive, TIC54X 598@cindex @code{tag} directive, TIC54X 599@cindex @code{endstruct} directive, TIC54X 600@item [@var{stag}] .struct [@var{offset}] 601@itemx [@var{name_1}] element [@var{count_1}] 602@itemx [@var{name_2}] element [@var{count_2}] 603@itemx [@var{tname}] .tag @var{stagx} [@var{tcount}] 604@itemx ... 605@itemx [@var{name_n}] element [@var{count_n}] 606@itemx [@var{ssize}] .endstruct 607@itemx @var{label} .tag [@var{stag}] 608Assign symbolic offsets to the elements of a structure. @var{stag} 609defines a symbol to use to reference the structure. @var{offset} 610indicates a starting value to use for the first element encountered; 611otherwise it defaults to zero. Each element can have a named offset, 612@var{name}, which is a symbol assigned the value of the element's offset 613into the structure. If @var{stag} is missing, these become global 614symbols. @var{count} adjusts the offset that many times, as if 615@code{element} were an array. @code{element} may be one of 616@code{.byte}, @code{.word}, @code{.long}, @code{.float}, or any 617equivalent of those, and the structure offset is adjusted accordingly. 618@code{.field} and @code{.string} are also allowed; the size of 619@code{.field} is one bit, and @code{.string} is considered to be one 620word in size. Only element descriptors, structure/union tags, 621@code{.align} and conditional assembly directives are allowed within 622@code{.struct}/@code{.endstruct}. @code{.align} aligns member offsets 623to word boundaries only. @var{ssize}, if provided, will always be 624assigned the size of the structure. 625 626The @code{.tag} directive, in addition to being used to define a 627structure/union element within a structure, may be used to apply a 628structure to a symbol. Once applied to @var{label}, the individual 629structure elements may be applied to @var{label} to produce the desired 630offsets using @var{label} as the structure base. 631 632@cindex @code{tab} directive, TIC54X 633@item .tab 634Set the tab size in the output listing. Ignored. 635 636@cindex @code{union} directive, TIC54X 637@cindex @code{tag} directive, TIC54X 638@cindex @code{endunion} directive, TIC54X 639@item [@var{utag}] .union 640@itemx [@var{name_1}] element [@var{count_1}] 641@itemx [@var{name_2}] element [@var{count_2}] 642@itemx [@var{tname}] .tag @var{utagx}[,@var{tcount}] 643@itemx ... 644@itemx [@var{name_n}] element [@var{count_n}] 645@itemx [@var{usize}] .endstruct 646@itemx @var{label} .tag [@var{utag}] 647Similar to @code{.struct}, but the offset after each element is reset to 648zero, and the @var{usize} is set to the maximum of all defined elements. 649Starting offset for the union is always zero. 650 651@cindex @code{usect} directive, TIC54X 652@item [@var{symbol}] .usect "@var{section_name}", @var{size}, [,[@var{blocking_flag}] [,@var{alignment_flag}]] 653Reserve space for variables in a named, uninitialized section (similar to 654.bss). @code{.usect} allows definitions sections independent of .bss. 655@var{symbol} points to the first location reserved by this allocation. 656The symbol may be used as a variable name. @var{size} is the allocated 657size in words. @var{blocking_flag} indicates whether to block this 658section on a page boundary (128 words) (@pxref{TIC54X-Block}). 659@var{alignment flag} indicates whether the section should be 660longword-aligned. 661 662@cindex @code{var} directive, TIC54X 663@item .var @var{sym}[,..., @var{sym_n}] 664Define a subsym to be a local variable within a macro. See 665@xref{TIC54X-Macros}. 666 667@cindex @code{version} directive, TIC54X 668@item .version @var{version} 669Set which processor to build instructions for. Though the following 670values are accepted, the op is ignored. 671@table @code 672@item 541 673@itemx 542 674@itemx 543 675@itemx 545 676@itemx 545LP 677@itemx 546LP 678@itemx 548 679@itemx 549 680@end table 681@end table 682 683@node TIC54X-Macros 684@section Macros 685 686@cindex TIC54X-specific macros 687@cindex macros, TIC54X 688Macros do not require explicit dereferencing of arguments (i.e. \ARG). 689 690During macro expansion, the macro parameters are converted to subsyms. 691If the number of arguments passed the macro invocation exceeds the 692number of parameters defined, the last parameter is assigned the string 693equivalent of all remaining arguments. If fewer arguments are given 694than parameters, the missing parameters are assigned empty strings. To 695include a comma in an argument, you must enclose the argument in quotes. 696 697@cindex subsym builtins, TIC54X 698@cindex TIC54X subsym builtins 699@cindex builtin subsym functions, TIC54X 700The following built-in subsym functions allow examination of the string 701value of subsyms (or ordinary strings). The arguments are strings 702unless otherwise indicated (subsyms passed as args will be replaced by 703the strings they represent). 704@table @code 705@cindex @code{$symlen} subsym builtin, TIC54X 706@item @code{$symlen(@var{str})} 707Returns the length of @var{str}. 708 709@cindex @code{$symcmp} subsym builtin, TIC54X 710@item @code{$symcmp(@var{str1},@var{str2})} 711Returns 0 if @var{str1} == @var{str2}, non-zero otherwise. 712 713@cindex @code{$firstch} subsym builtin, TIC54X 714@item @code{$firstch(@var{str},@var{ch})} 715Returns index of the first occurrence of character constant @var{ch} in 716@var{str}. 717 718@cindex @code{$lastch} subsym builtin, TIC54X 719@item @code{$lastch(@var{str},@var{ch})} 720Returns index of the last occurrence of character constant @var{ch} in 721@var{str}. 722 723@cindex @code{$isdefed} subsym builtin, TIC54X 724@item @code{$isdefed(@var{symbol})} 725Returns zero if the symbol @var{symbol} is not in the symbol table, 726non-zero otherwise. 727 728@cindex @code{$ismember} subsym builtin, TIC54X 729@item @code{$ismember(@var{symbol},@var{list})} 730Assign the first member of comma-separated string @var{list} to 731@var{symbol}; @var{list} is reassigned the remainder of the list. Returns 732zero if @var{list} is a null string. Both arguments must be subsyms. 733 734@cindex @code{$iscons} subsym builtin, TIC54X 735@item @code{$iscons(@var{expr})} 736Returns 1 if string @var{expr} is binary, 2 if octal, 3 if hexadecimal, 7374 if a character, 5 if decimal, and zero if not an integer. 738 739@cindex @code{$isname} subsym builtin, TIC54X 740@item @code{$isname(@var{name})} 741Returns 1 if @var{name} is a valid symbol name, zero otherwise. 742 743@cindex @code{$isreg} subsym builtin, TIC54X 744@item @code{$isreg(@var{reg})} 745Returns 1 if @var{reg} is a valid predefined register name (AR0-AR7 only). 746 747@cindex @code{$structsz} subsym builtin, TIC54X 748@item @code{$structsz(@var{stag})} 749Returns the size of the structure or union represented by @var{stag}. 750 751@cindex @code{$structacc} subsym builtin, TIC54X 752@item @code{$structacc(@var{stag})} 753Returns the reference point of the structure or union represented by 754@var{stag}. Always returns zero. 755 756@end table 757 758@node TIC54X-MMRegs 759@section Memory-mapped Registers 760 761@cindex TIC54X memory-mapped registers 762@cindex registers, TIC54X memory-mapped 763@cindex memory-mapped registers, TIC54X 764The following symbols are recognized as memory-mapped registers: 765 766@table @code 767@end table 768