@c Copyright (C) 2006-2020 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 AVR-Dependent
@chapter AVR Dependent Features
@end ifset
@ifclear GENERIC
@node Machine Dependencies
@chapter AVR Dependent Features
@end ifclear
@cindex AVR support
@menu
* AVR Options:: Options
* AVR Syntax:: Syntax
* AVR Opcodes:: Opcodes
* AVR Pseudo Instructions:: Pseudo Instructions
@end menu
@node AVR Options
@section Options
@cindex AVR options (none)
@cindex options for AVR (none)
@table @code
@cindex @code{-mmcu=} command-line option, AVR
@item -mmcu=@var{mcu}
Specify ATMEL AVR instruction set or MCU type.
Instruction set avr1 is for the minimal AVR core, not supported by the C
compiler, only for assembler programs (MCU types: at90s1200,
attiny11, attiny12, attiny15, attiny28).
Instruction set avr2 (default) is for the classic AVR core with up to
8K program memory space (MCU types: at90s2313, at90s2323, at90s2333, at90s2343,
attiny22, attiny26, at90s4414, at90s4433, at90s4434, at90s8515, at90c8534,
at90s8535).
Instruction set avr25 is for the classic AVR core with up to 8K program memory
space plus the MOVW instruction (MCU types: attiny13, attiny13a, attiny2313,
attiny2313a, attiny24, attiny24a, attiny4313, attiny44, attiny44a, attiny84,
attiny84a, attiny25, attiny45, attiny85, attiny261, attiny261a, attiny461,
attiny461a, attiny861, attiny861a, attiny87, attiny43u, attiny48, attiny88,
attiny828, at86rf401, ata6289, ata5272).
Instruction set avr3 is for the classic AVR core with up to 128K program
memory space (MCU types: at43usb355, at76c711).
Instruction set avr31 is for the classic AVR core with exactly 128K program
memory space (MCU types: atmega103, at43usb320).
Instruction set avr35 is for classic AVR core plus MOVW, CALL, and JMP
instructions (MCU types: attiny167, attiny1634, at90usb82, at90usb162,
atmega8u2, atmega16u2, atmega32u2, ata5505).
Instruction set avr4 is for the enhanced AVR core with up to 8K program
memory space (MCU types: atmega48, atmega48a, atmega48pa, atmega48p, atmega8,
atmega8a, atmega88, atmega88a, atmega88p, atmega88pa, atmega8515, atmega8535,
atmega8hva, at90pwm1, at90pwm2, at90pwm2b, at90pwm3, at90pwm3b, at90pwm81,
ata6285, ata6286).
Instruction set avr5 is for the enhanced AVR core with up to 128K program
memory space (MCU types: at90pwm161, atmega16, atmega16a, atmega161, atmega162,
atmega163, atmega164a, atmega164p, atmega164pa, atmega165, atmega165a,
atmega165p, atmega165pa, atmega168, atmega168a, atmega168p, atmega168pa,
atmega169, atmega169a, atmega169p, atmega169pa, atmega32, atmega323, atmega324a,
atmega324p, atmega324pa, atmega325, atmega325a, atmega32, atmega32a, atmega323,
atmega324a, atmega324p, atmega324pa, atmega325, atmega325a, atmega325p,
atmega325p, atmega325pa, atmega3250, atmega3250a, atmega3250p, atmega3250pa,
atmega328, atmega328p, atmega329, atmega329a, atmega329p, atmega329pa,
atmega3290a, atmega3290p, atmega3290pa, atmega406, atmega64, atmega64a,
atmega64rfr2, atmega644rfr2, atmega640, atmega644, atmega644a, atmega644p,
atmega644pa, atmega645, atmega645a, atmega645p, atmega6450, atmega6450a,
atmega6450p, atmega649, atmega649a, atmega649p, atmega6490, atmega6490a,
atmega6490p, atmega16hva, atmega16hva2, atmega16hvb, atmega16hvbrevb,
atmega32hvb, atmega32hvbrevb, atmega64hve, at90can32, at90can64, at90pwm161,
at90pwm216, at90pwm316, atmega32c1, atmega64c1, atmega16m1, atmega32m1,
atmega64m1, atmega16u4, atmega32u4, atmega32u6, at90usb646, at90usb647, at94k,
at90scr100, ata5790, ata5795).
Instruction set avr51 is for the enhanced AVR core with exactly 128K
program memory space (MCU types: atmega128, atmega128a, atmega1280,
atmega1281, atmega1284, atmega1284p, atmega128rfa1, atmega128rfr2,
atmega1284rfr2, at90can128, at90usb1286, at90usb1287, m3000).
Instruction set avr6 is for the enhanced AVR core with a 3-byte PC
(MCU types: atmega2560, atmega2561, atmega256rfr2, atmega2564rfr2).
Instruction set avrxmega2 is for the XMEGA AVR core with 8K to 64K
program memory space and less than 64K data space (MCU types:
atxmega16a4, atxmega16a4u, atxmega16c4, atxmega16d4, atxmega16x1,
atxmega32a4, atxmega32a4u, atxmega32c4, atxmega32d4, atxmega16e5,
atxmega8e5, atxmega32e5, atxmega32x1).
Instruction set avrxmega3 is for the XMEGA AVR core with up to 64K
of combined program memory and RAM, and with program memory
visible in the RAM address space (MCU types:
attiny212, attiny214, attiny412, attiny414, attiny416, attiny417,
attiny814, attiny816, attiny817, attiny1614, attiny1616, attiny1617,
attiny3214, attiny3216, attiny3217).
Instruction set avrxmega4 is for the XMEGA AVR core with up to 64K
program memory space and less than 64K data space (MCU types:
atxmega64a3, atxmega64a3u, atxmega64a4u, atxmega64b1, atxmega64b3,
atxmega64c3, atxmega64d3, atxmega64d4).
Instruction set avrxmega5 is for the XMEGA AVR core with up to 64K
program memory space and greater than 64K data space (MCU types:
atxmega64a1, atxmega64a1u).
Instruction set avrxmega6 is for the XMEGA AVR core with larger than
64K program memory space and less than 64K data space (MCU types:
atxmega128a3, atxmega128a3u, atxmega128c3, atxmega128d3, atxmega128d4,
atxmega192a3, atxmega192a3u, atxmega128b1, atxmega128b3, atxmega192c3,
atxmega192d3, atxmega256a3, atxmega256a3u, atxmega256a3b,
atxmega256a3bu, atxmega256c3, atxmega256d3, atxmega384c3,
atxmega256d3).
Instruction set avrxmega7 is for the XMEGA AVR core with larger than
64K program memory space and greater than 64K data space (MCU types:
atxmega128a1, atxmega128a1u, atxmega128a4u).
Instruction set avrtiny is for the ATtiny4/5/9/10/20/40
microcontrollers.
@cindex @code{-mall-opcodes} command-line option, AVR
@item -mall-opcodes
Accept all AVR opcodes, even if not supported by @code{-mmcu}.
@cindex @code{-mno-skip-bug} command-line option, AVR
@item -mno-skip-bug
This option disable warnings for skipping two-word instructions.
@cindex @code{-mno-wrap} command-line option, AVR
@item -mno-wrap
This option reject @code{rjmp/rcall} instructions with 8K wrap-around.
@cindex @code{-mrmw} command-line option, AVR
@item -mrmw
Accept Read-Modify-Write (@code{XCH,LAC,LAS,LAT}) instructions.
@cindex @code{-mlink-relax} command-line option, AVR
@item -mlink-relax
Enable support for link-time relaxation. This is now on by default
and this flag no longer has any effect.
@cindex @code{-mno-link-relax} command-line option, AVR
@item -mno-link-relax
Disable support for link-time relaxation. The assembler will resolve
relocations when it can, and may be able to better compress some debug
information.
@cindex @code{-mgcc-isr} command-line option, AVR
@item -mgcc-isr
Enable the @code{__gcc_isr} pseudo instruction.
@end table
@node AVR Syntax
@section Syntax
@menu
* AVR-Chars:: Special Characters
* AVR-Regs:: Register Names
* AVR-Modifiers:: Relocatable Expression Modifiers
@end menu
@node AVR-Chars
@subsection Special Characters
@cindex line comment character, AVR
@cindex AVR line comment character
The presence of a @samp{;} 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, 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, AVR
@cindex statement separator, AVR
@cindex AVR line separator
The @samp{$} character can be used instead of a newline to separate
statements.
@node AVR-Regs
@subsection Register Names
@cindex AVR register names
@cindex register names, AVR
The AVR has 32 x 8-bit general purpose working registers @samp{r0},
@samp{r1}, ... @samp{r31}.
Six of the 32 registers can be used as three 16-bit indirect address
register pointers for Data Space addressing. One of the these address
pointers can also be used as an address pointer for look up tables in
Flash program memory. These added function registers are the 16-bit
@samp{X}, @samp{Y} and @samp{Z} - registers.
@smallexample
X = @r{r26:r27}
Y = @r{r28:r29}
Z = @r{r30:r31}
@end smallexample
@node AVR-Modifiers
@subsection Relocatable Expression Modifiers
@cindex AVR modifiers
@cindex syntax, AVR
The assembler supports several modifiers when using relocatable addresses
in AVR instruction operands. The general syntax is the following:
@smallexample
modifier(relocatable-expression)
@end smallexample
@table @code
@cindex symbol modifiers
@item lo8
This modifier allows you to use bits 0 through 7 of
an address expression as 8 bit relocatable expression.
@item hi8
This modifier allows you to use bits 7 through 15 of an address expression
as 8 bit relocatable expression. This is useful with, for example, the
AVR @samp{ldi} instruction and @samp{lo8} modifier.
For example
@smallexample
ldi r26, lo8(sym+10)
ldi r27, hi8(sym+10)
@end smallexample
@item hh8
This modifier allows you to use bits 16 through 23 of
an address expression as 8 bit relocatable expression.
Also, can be useful for loading 32 bit constants.
@item hlo8
Synonym of @samp{hh8}.
@item hhi8
This modifier allows you to use bits 24 through 31 of
an expression as 8 bit expression. This is useful with, for example, the
AVR @samp{ldi} instruction and @samp{lo8}, @samp{hi8}, @samp{hlo8},
@samp{hhi8}, modifier.
For example
@smallexample
ldi r26, lo8(285774925)
ldi r27, hi8(285774925)
ldi r28, hlo8(285774925)
ldi r29, hhi8(285774925)
; r29,r28,r27,r26 = 285774925
@end smallexample
@item pm_lo8
This modifier allows you to use bits 0 through 7 of
an address expression as 8 bit relocatable expression.
This modifier useful for addressing data or code from
Flash/Program memory. The using of @samp{pm_lo8} similar
to @samp{lo8}.
@item pm_hi8
This modifier allows you to use bits 8 through 15 of
an address expression as 8 bit relocatable expression.
This modifier useful for addressing data or code from
Flash/Program memory.
@item pm_hh8
This modifier allows you to use bits 15 through 23 of
an address expression as 8 bit relocatable expression.
This modifier useful for addressing data or code from
Flash/Program memory.
@end table
@node AVR Opcodes
@section Opcodes
@cindex AVR opcode summary
@cindex opcode summary, AVR
@cindex mnemonics, AVR
@cindex instruction summary, AVR
For detailed information on the AVR machine instruction set, see
@url{www.atmel.com/products/AVR}.
@code{@value{AS}} implements all the standard AVR opcodes.
The following table summarizes the AVR opcodes, and their arguments.
@smallexample
@i{Legend:}
r @r{any register}
d @r{`ldi' register (r16-r31)}
v @r{`movw' even register (r0, r2, ..., r28, r30)}
a @r{`fmul' register (r16-r23)}
w @r{`adiw' register (r24,r26,r28,r30)}
e @r{pointer registers (X,Y,Z)}
b @r{base pointer register and displacement ([YZ]+disp)}
z @r{Z pointer register (for [e]lpm Rd,Z[+])}
M @r{immediate value from 0 to 255}
n @r{immediate value from 0 to 255 ( n = ~M ). Relocation impossible}
s @r{immediate value from 0 to 7}
P @r{Port address value from 0 to 63. (in, out)}
p @r{Port address value from 0 to 31. (cbi, sbi, sbic, sbis)}
K @r{immediate value from 0 to 63 (used in `adiw', `sbiw')}
i @r{immediate value}
l @r{signed pc relative offset from -64 to 63}
L @r{signed pc relative offset from -2048 to 2047}
h @r{absolute code address (call, jmp)}
S @r{immediate value from 0 to 7 (S = s << 4)}
? @r{use this opcode entry if no parameters, else use next opcode entry}
1001010010001000 clc
1001010011011000 clh
1001010011111000 cli
1001010010101000 cln
1001010011001000 cls
1001010011101000 clt
1001010010111000 clv
1001010010011000 clz
1001010000001000 sec
1001010001011000 seh
1001010001111000 sei
1001010000101000 sen
1001010001001000 ses
1001010001101000 set
1001010000111000 sev
1001010000011000 sez
100101001SSS1000 bclr S
100101000SSS1000 bset S
1001010100001001 icall
1001010000001001 ijmp
1001010111001000 lpm ?
1001000ddddd010+ lpm r,z
1001010111011000 elpm ?
1001000ddddd011+ elpm r,z
0000000000000000 nop
1001010100001000 ret
1001010100011000 reti
1001010110001000 sleep
1001010110011000 break
1001010110101000 wdr
1001010111101000 spm
000111rdddddrrrr adc r,r
000011rdddddrrrr add r,r
001000rdddddrrrr and r,r
000101rdddddrrrr cp r,r
000001rdddddrrrr cpc r,r
000100rdddddrrrr cpse r,r
001001rdddddrrrr eor r,r
001011rdddddrrrr mov r,r
100111rdddddrrrr mul r,r
001010rdddddrrrr or r,r
000010rdddddrrrr sbc r,r
000110rdddddrrrr sub r,r
001001rdddddrrrr clr r
000011rdddddrrrr lsl r
000111rdddddrrrr rol r
001000rdddddrrrr tst r
0111KKKKddddKKKK andi d,M
0111KKKKddddKKKK cbr d,n
1110KKKKddddKKKK ldi d,M
11101111dddd1111 ser d
0110KKKKddddKKKK ori d,M
0110KKKKddddKKKK sbr d,M
0011KKKKddddKKKK cpi d,M
0100KKKKddddKKKK sbci d,M
0101KKKKddddKKKK subi d,M
1111110rrrrr0sss sbrc r,s
1111111rrrrr0sss sbrs r,s
1111100ddddd0sss bld r,s
1111101ddddd0sss bst r,s
10110PPdddddPPPP in r,P
10111PPrrrrrPPPP out P,r
10010110KKddKKKK adiw w,K
10010111KKddKKKK sbiw w,K
10011000pppppsss cbi p,s
10011010pppppsss sbi p,s
10011001pppppsss sbic p,s
10011011pppppsss sbis p,s
111101lllllll000 brcc l
111100lllllll000 brcs l
111100lllllll001 breq l
111101lllllll100 brge l
111101lllllll101 brhc l
111100lllllll101 brhs l
111101lllllll111 brid l
111100lllllll111 brie l
111100lllllll000 brlo l
111100lllllll100 brlt l
111100lllllll010 brmi l
111101lllllll001 brne l
111101lllllll010 brpl l
111101lllllll000 brsh l
111101lllllll110 brtc l
111100lllllll110 brts l
111101lllllll011 brvc l
111100lllllll011 brvs l
111101lllllllsss brbc s,l
111100lllllllsss brbs s,l
1101LLLLLLLLLLLL rcall L
1100LLLLLLLLLLLL rjmp L
1001010hhhhh111h call h
1001010hhhhh110h jmp h
1001010rrrrr0101 asr r
1001010rrrrr0000 com r
1001010rrrrr1010 dec r
1001010rrrrr0011 inc r
1001010rrrrr0110 lsr r
1001010rrrrr0001 neg r
1001000rrrrr1111 pop r
1001001rrrrr1111 push r
1001010rrrrr0111 ror r
1001010rrrrr0010 swap r
00000001ddddrrrr movw v,v
00000010ddddrrrr muls d,d
000000110ddd0rrr mulsu a,a
000000110ddd1rrr fmul a,a
000000111ddd0rrr fmuls a,a
000000111ddd1rrr fmulsu a,a
1001001ddddd0000 sts i,r
1001000ddddd0000 lds r,i
10o0oo0dddddbooo ldd r,b
100!000dddddee-+ ld r,e
10o0oo1rrrrrbooo std b,r
100!001rrrrree-+ st e,r
1001010100011001 eicall
1001010000011001 eijmp
@end smallexample
@node AVR Pseudo Instructions
@section Pseudo Instructions
The only available pseudo-instruction @code{__gcc_isr} can be activated by
option @option{-mgcc-isr}.
@table @code
@item __gcc_isr 1
Emit code chunk to be used in avr-gcc ISR prologue.
It will expand to at most six 1-word instructions, all optional:
push of @code{tmp_reg}, push of @code{SREG},
push and clear of @code{zero_reg}, push of @var{Reg}.
@item __gcc_isr 2
Emit code chunk to be used in an avr-gcc ISR epilogue.
It will expand to at most five 1-word instructions, all optional:
pop of @var{Reg}, pop of @code{zero_reg},
pop of @code{SREG}, pop of @code{tmp_reg}.
@item __gcc_isr 0, @var{Reg}
Finish avr-gcc ISR function. Scan code since the last prologue
for usage of: @code{SREG}, @code{tmp_reg}, @code{zero_reg}.
Prologue chunk and epilogue chunks will be replaced by appropriate code
to save / restore @code{SREG}, @code{tmp_reg}, @code{zero_reg} and @var{Reg}.
@end table
Example input:
@example
__vector1:
__gcc_isr 1
lds r24, var
inc r24
sts var, r24
__gcc_isr 2
reti
__gcc_isr 0, r24
@end example
Example output:
@example
00000000 <__vector1>:
0: 8f 93 push r24
2: 8f b7 in r24, 0x3f
4: 8f 93 push r24
6: 80 91 60 00 lds r24, 0x0060 ; 0x800060 <var>
a: 83 95 inc r24
c: 80 93 60 00 sts 0x0060, r24 ; 0x800060 <var>
10: 8f 91 pop r24
12: 8f bf out 0x3f, r24
14: 8f 91 pop r24
16: 18 95 reti
@end example