gas/doc/c-avr.texi

   1 @c Copyright 2006
   2 @c Free Software Foundation, Inc.
   3 @c This is part of the GAS manual.
   4 @c For copying conditions, see the file as.texinfo.
   5
   6 @ifset GENERIC
   7 @page
   8 @node AVR-Dependent
   9 @chapter AVR Dependent Features
  10 @end ifset
  11
  12 @ifclear GENERIC
  13 @node Machine Dependencies
  14 @chapter AVR Dependent Features
  15 @end ifclear
  16
  17 @cindex AVR support
  18 @menu
  19 * AVR Options::              Options
  20 * AVR Syntax::               Syntax
  21 * AVR Opcodes::              Opcodes
  22 @end menu
  23
  24 @node AVR Options
  25 @section Options
  26 @cindex AVR options (none)
  27 @cindex options for AVR (none)
  28
  29 @table @code
  30
  31 @cindex @code{-mmcu=} command line option, AVR
  32 @item -mmcu=@var{mcu}
  33 Specify ATMEL AVR instruction set or MCU type.
  34
  35 Instruction set avr1 is for the minimal AVR core, not supported by the C
  36 compiler, only for assembler programs (MCU types: at90s1200, attiny10,
  37 attiny11, attiny12, attiny15, attiny28).
  38
  39 Instruction set avr2 (default) is for the classic AVR core with up to
  40 8K program memory space (MCU types: at90s2313, at90s2323, attiny22,
  41 attiny26, at90s2333, at90s2343, at90s4414, at90s4433, at90s4434,
  42 at90s8515, at90c8534, at90s8535, at86rf401, attiny13, attiny2313,
  43 attiny261, attiny461, attiny861, attiny24, attiny44, attiny84, attiny25,
  44 attiny45, attiny85).
  45
  46 Instruction set avr3 is for the classic AVR core with up to 128K program
  47 memory space (MCU types: atmega103, atmega603, at43usb320, at43usb355,
  48 at76c711).
  49
  50 Instruction set avr4 is for the enhanced AVR core with up to 8K program
  51 memory space (MCU types: atmega48, atmega8, atmega83, atmega85, atmega88,
  52 atmega8515, atmega8535, at90pwm2, at90pwm3).
  53
  54 Instruction set avr5 is for the enhanced AVR core with up to 128K program
  55 memory space (MCU types: atmega16, atmega161, atmega162, atmega163,
  56 atmega164p, atmega165, atmega165p, atmega168, atmega169, atmega169p,
  57 atmega32, atmega323, atmega324p, atmega325, atmega329, atmega3250,
  58 atmega3290, atmega406, atmega64, atmega640, atmega644, atmega644p,
  59 atmega128, atmega1280, atmega1281, atmega645, atmega649, atmega6450,
  60 atmega6490, at90can32, at90can64, at90can128, at90usb646, at90usb647,
  61 at90usb1286, at90usb1287, at94k).
  62
  63 Instruction set avr6 is for the enhanced AVR core with 256K program
  64 memory space (MCU types: atmega2560, atmega2561).
  65
  66 @cindex @code{-mall-opcodes} command line option, AVR
  67 @item -mall-opcodes
  68 Accept all AVR opcodes, even if not supported by @code{-mmcu}.
  69
  70 @cindex @code{-mno-skip-bug} command line option, AVR
  71 @item -mno-skip-bug
  72 This option disable warnings for skipping two-word instructions.
  73
  74 @cindex @code{-mno-wrap} command line option, AVR
  75 @item -mno-wrap
  76 This option reject @code{rjmp/rcall} instructions with 8K wrap-around.
  77
  78 @end table
  79
  80
  81 @node AVR Syntax
  82 @section Syntax
  83 @menu
  84 * AVR-Chars::                Special Characters
  85 * AVR-Regs::                 Register Names
  86 * AVR-Modifiers::            Relocatable Expression Modifiers
  87 @end menu
  88
  89 @node AVR-Chars
  90 @subsection Special Characters
  91
  92 @cindex line comment character, AVR
  93 @cindex AVR line comment character
  94
  95 The presence of a @samp{;} on a line indicates the start of a comment
  96 that extends to the end of the current line.  If a @samp{#} appears as
  97 the first character of a line, the whole line is treated as a comment.
  98
  99 @cindex line separator, AVR
 100 @cindex statement separator, AVR
 101 @cindex AVR line separator
 102
 103 The @samp{$} character can be used instead of a newline to separate
 104 statements.
 105
 106 @node AVR-Regs
 107 @subsection Register Names
 108
 109 @cindex AVR register names
 110 @cindex register names, AVR
 111
 112 The AVR has 32 x 8-bit general purpouse working registers @samp{r0},
 113 @samp{r1}, ... @samp{r31}.
 114 Six of the 32 registers can be used as three 16-bit indirect address
 115 register pointers for Data Space addressing. One of the these address
 116 pointers can also be used as an address pointer for look up tables in
 117 Flash program memory. These added function registers are the 16-bit
 118 @samp{X}, @samp{Y} and @samp{Z} - registers.
 119
 120 @smallexample
 121 X = @r{r26:r27}
 122 Y = @r{r28:r29}
 123 Z = @r{r30:r31}
 124 @end smallexample
 125
 126 @node AVR-Modifiers
 127 @subsection Relocatable Expression Modifiers
 128
 129 @cindex AVR modifiers
 130 @cindex syntax, AVR
 131
 132 The assembler supports several modifiers when using relocatable addresses
 133 in AVR instruction operands.  The general syntax is the following:
 134
 135 @smallexample
 136 modifier(relocatable-expression)
 137 @end smallexample
 138
 139 @table @code
 140 @cindex symbol modifiers
 141
 142 @item lo8
 143
 144 This modifier allows you to use bits 0 through 7 of
 145 an address expression as 8 bit relocatable expression.
 146
 147 @item hi8
 148
 149 This modifier allows you to use bits 7 through 15 of an address expression
 150 as 8 bit relocatable expression.  This is useful with, for example, the
 151 AVR @samp{ldi} instruction and @samp{lo8} modifier.
 152
 153 For example
 154
 155 @smallexample
 156 ldi r26, lo8(sym+10)
 157 ldi r27, hi8(sym+10)
 158 @end smallexample
 159
 160 @item hh8
 161
 162 This modifier allows you to use bits 16 through 23 of
 163 an address expression as 8 bit relocatable expression.
 164 Also, can be useful for loading 32 bit constants.
 165
 166 @item hlo8
 167
 168 Synonym of @samp{hh8}.
 169
 170 @item hhi8
 171
 172 This modifier allows you to use bits 24 through 31 of
 173 an expression as 8 bit expression. This is useful with, for example, the
 174 AVR @samp{ldi} instruction and @samp{lo8}, @samp{hi8}, @samp{hlo8},
 175 @samp{hhi8}, modifier.
 176
 177 For example
 178
 179 @smallexample
 180 ldi r26, lo8(285774925)
 181 ldi r27, hi8(285774925)
 182 ldi r28, hlo8(285774925)
 183 ldi r29, hhi8(285774925)
 184 ; r29,r28,r27,r26 = 285774925
 185 @end smallexample
 186
 187 @item pm_lo8
 188
 189 This modifier allows you to use bits 0 through 7 of
 190 an address expression as 8 bit relocatable expression.
 191 This modifier useful for addressing data or code from
 192 Flash/Program memory. The using of @samp{pm_lo8} similar
 193 to @samp{lo8}.
 194
 195 @item pm_hi8
 196
 197 This modifier allows you to use bits 8 through 15 of
 198 an address expression as 8 bit relocatable expression.
 199 This modifier useful for addressing data or code from
 200 Flash/Program memory.
 201
 202 @item pm_hh8
 203
 204 This modifier allows you to use bits 15 through 23 of
 205 an address expression as 8 bit relocatable expression.
 206 This modifier useful for addressing data or code from
 207 Flash/Program memory.
 208
 209 @end table
 210
 211 @node AVR Opcodes
 212 @section Opcodes
 213
 214 @cindex AVR opcode summary
 215 @cindex opcode summary, AVR
 216 @cindex mnemonics, AVR
 217 @cindex instruction summary, AVR
 218 For detailed information on the AVR machine instruction set, see
 219 @url{www.atmel.com/products/AVR}.
 220
 221 @code{@value{AS}} implements all the standard AVR opcodes.
 222 The following table summarizes the AVR opcodes, and their arguments.
 223
 224 @smallexample
 225 @i{Legend:}
 226    r   @r{any register}
 227    d   @r{`ldi' register (r16-r31)}
 228    v   @r{`movw' even register (r0, r2, ..., r28, r30)}
 229    a   @r{`fmul' register (r16-r23)}
 230    w   @r{`adiw' register (r24,r26,r28,r30)}
 231    e   @r{pointer registers (X,Y,Z)}
 232    b   @r{base pointer register and displacement ([YZ]+disp)}
 233    z   @r{Z pointer register (for [e]lpm Rd,Z[+])}
 234    M   @r{immediate value from 0 to 255}
 235    n   @r{immediate value from 0 to 255 ( n = ~M ). Relocation impossible}
 236    s   @r{immediate value from 0 to 7}
 237    P   @r{Port address value from 0 to 63. (in, out)}
 238    p   @r{Port address value from 0 to 31. (cbi, sbi, sbic, sbis)}
 239    K   @r{immediate value from 0 to 63 (used in `adiw', `sbiw')}
 240    i   @r{immediate value}
 241    l   @r{signed pc relative offset from -64 to 63}
 242    L   @r{signed pc relative offset from -2048 to 2047}
 243    h   @r{absolute code address (call, jmp)}
 244    S   @r{immediate value from 0 to 7 (S = s << 4)}
 245    ?   @r{use this opcode entry if no parameters, else use next opcode entry}
 246
 247 1001010010001000   clc
 248 1001010011011000   clh
 249 1001010011111000   cli
 250 1001010010101000   cln
 251 1001010011001000   cls
 252 1001010011101000   clt
 253 1001010010111000   clv
 254 1001010010011000   clz
 255 1001010000001000   sec
 256 1001010001011000   seh
 257 1001010001111000   sei
 258 1001010000101000   sen
 259 1001010001001000   ses
 260 1001010001101000   set
 261 1001010000111000   sev
 262 1001010000011000   sez
 263 100101001SSS1000   bclr    S
 264 100101000SSS1000   bset    S
 265 1001010100001001   icall
 266 1001010000001001   ijmp
 267 1001010111001000   lpm     ?
 268 1001000ddddd010+   lpm     r,z
 269 1001010111011000   elpm    ?
 270 1001000ddddd011+   elpm    r,z
 271 0000000000000000   nop
 272 1001010100001000   ret
 273 1001010100011000   reti
 274 1001010110001000   sleep
 275 1001010110011000   break
 276 1001010110101000   wdr
 277 1001010111101000   spm
 278 000111rdddddrrrr   adc     r,r
 279 000011rdddddrrrr   add     r,r
 280 001000rdddddrrrr   and     r,r
 281 000101rdddddrrrr   cp      r,r
 282 000001rdddddrrrr   cpc     r,r
 283 000100rdddddrrrr   cpse    r,r
 284 001001rdddddrrrr   eor     r,r
 285 001011rdddddrrrr   mov     r,r
 286 100111rdddddrrrr   mul     r,r
 287 001010rdddddrrrr   or      r,r
 288 000010rdddddrrrr   sbc     r,r
 289 000110rdddddrrrr   sub     r,r
 290 001001rdddddrrrr   clr     r
 291 000011rdddddrrrr   lsl     r
 292 000111rdddddrrrr   rol     r
 293 001000rdddddrrrr   tst     r
 294 0111KKKKddddKKKK   andi    d,M
 295 0111KKKKddddKKKK   cbr     d,n
 296 1110KKKKddddKKKK   ldi     d,M
 297 11101111dddd1111   ser     d
 298 0110KKKKddddKKKK   ori     d,M
 299 0110KKKKddddKKKK   sbr     d,M
 300 0011KKKKddddKKKK   cpi     d,M
 301 0100KKKKddddKKKK   sbci    d,M
 302 0101KKKKddddKKKK   subi    d,M
 303 1111110rrrrr0sss   sbrc    r,s
 304 1111111rrrrr0sss   sbrs    r,s
 305 1111100ddddd0sss   bld     r,s
 306 1111101ddddd0sss   bst     r,s
 307 10110PPdddddPPPP   in      r,P
 308 10111PPrrrrrPPPP   out     P,r
 309 10010110KKddKKKK   adiw    w,K
 310 10010111KKddKKKK   sbiw    w,K
 311 10011000pppppsss   cbi     p,s
 312 10011010pppppsss   sbi     p,s
 313 10011001pppppsss   sbic    p,s
 314 10011011pppppsss   sbis    p,s
 315 111101lllllll000   brcc    l
 316 111100lllllll000   brcs    l
 317 111100lllllll001   breq    l
 318 111101lllllll100   brge    l
 319 111101lllllll101   brhc    l
 320 111100lllllll101   brhs    l
 321 111101lllllll111   brid    l
 322 111100lllllll111   brie    l
 323 111100lllllll000   brlo    l
 324 111100lllllll100   brlt    l
 325 111100lllllll010   brmi    l
 326 111101lllllll001   brne    l
 327 111101lllllll010   brpl    l
 328 111101lllllll000   brsh    l
 329 111101lllllll110   brtc    l
 330 111100lllllll110   brts    l
 331 111101lllllll011   brvc    l
 332 111100lllllll011   brvs    l
 333 111101lllllllsss   brbc    s,l
 334 111100lllllllsss   brbs    s,l
 335 1101LLLLLLLLLLLL   rcall   L
 336 1100LLLLLLLLLLLL   rjmp    L
 337 1001010hhhhh111h   call    h
 338 1001010hhhhh110h   jmp     h
 339 1001010rrrrr0101   asr     r
 340 1001010rrrrr0000   com     r
 341 1001010rrrrr1010   dec     r
 342 1001010rrrrr0011   inc     r
 343 1001010rrrrr0110   lsr     r
 344 1001010rrrrr0001   neg     r
 345 1001000rrrrr1111   pop     r
 346 1001001rrrrr1111   push    r
 347 1001010rrrrr0111   ror     r
 348 1001010rrrrr0010   swap    r
 349 00000001ddddrrrr   movw    v,v
 350 00000010ddddrrrr   muls    d,d
 351 000000110ddd0rrr   mulsu   a,a
 352 000000110ddd1rrr   fmul    a,a
 353 000000111ddd0rrr   fmuls   a,a
 354 000000111ddd1rrr   fmulsu  a,a
 355 1001001ddddd0000   sts     i,r
 356 1001000ddddd0000   lds     r,i
 357 10o0oo0dddddbooo   ldd     r,b
 358 100!000dddddee-+   ld      r,e
 359 10o0oo1rrrrrbooo   std     b,r
 360 100!001rrrrree-+   st      e,r
 361 1001010100011001   eicall
 362 1001010000011001   eijmp
 363 @end smallexample