diff mbox series

[v38,03/22] target/avr: Add instruction decoding

Message ID 20191208183922.13757-4-mrolnik@gmail.com (mailing list archive)
State New, archived
Headers show
Series QEMU AVR 8 bit cores | expand

Commit Message

Michael Rolnik Dec. 8, 2019, 6:39 p.m. UTC
This includes:
- encoding of all 16 bit instructions
- encoding of all 32 bit instructions

Signed-off-by: Michael Rolnik <mrolnik@gmail.com>
Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
 target/avr/insn.decode | 194 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 194 insertions(+)
 create mode 100644 target/avr/insn.decode

Comments

Aleksandar Markovic Dec. 9, 2019, 7:37 p.m. UTC | #1
On Sunday, December 8, 2019, Michael Rolnik <mrolnik@gmail.com> wrote:

> This includes:
> - encoding of all 16 bit instructions
> - encoding of all 32 bit instructions
>
> Signed-off-by: Michael Rolnik <mrolnik@gmail.com>
> Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
> ---
>  target/avr/insn.decode | 194 +++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 194 insertions(+)
>  create mode 100644 target/avr/insn.decode
>
>
Hi, Michael,

Could you please reorder decoding definitions in this file following this
pattern:

#
# Arithmetic Instructions
#

< their decoding definitions in the order they appear in the ISA doc >

#
target/avr: Add instruction translation - Branch Instructions
#

< their decoding definitions in the order they appear in the ISA doc >

#
# Data Transfer Instructions
#

< their decoding definitions in the order they appear in the ISA doc >

#
# Bit and Bit-test Instructions
#

< their decoding definitions in the order they appear in the ISA doc >

#
# MCU Control Instructions
#

< their decoding definitions in the order they appear in the ISA doc >



Thanks in advance!

Aleksandar






> diff --git a/target/avr/insn.decode b/target/avr/insn.decode
> new file mode 100644
> index 0000000000..2eb6de692a
> --- /dev/null
> +++ b/target/avr/insn.decode
> @@ -0,0 +1,194 @@
> +#
> +# AVR instruction decode definitions.
> +#
> +# Copyright (c) 2019 Michael Rolnik <mrolnik@gmail.com>
> +#
> +# This library is free software; you can redistribute it and/or
> +# modify it under the terms of the GNU Lesser General Public
> +# License as published by the Free Software Foundation; either
> +# version 2.1 of the License, or (at your option) any later version.
> +#
> +# This library is distributed in the hope that it will be useful,
> +# but WITHOUT ANY WARRANTY; without even the implied warranty of
> +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> +# Lesser General Public License for more details.
> +#
> +# You should have received a copy of the GNU Lesser General Public
> +# License along with this library; if not, see <
> http://www.gnu.org/licenses/>.
> +#
> +
> +#
> +#   regs_16_31_by_one = [16 .. 31]
> +#   regs_16_23_by_one = [16 .. 23]
> +#   regs_24_30_by_two = [24, 26, 28, 30]
> +#   regs_00_30_by_two = [0, 2, 4, 6, 8, .. 30]
> +
> +%rd             4:5
> +%rr             9:1 0:4
> +
> +&rd_rr          rd rr
> +&rd_imm         rd imm
> +
> +@op_rd_rr       .... .. . ..... ....        &rd_rr      rd=%rd rr=%rr
> +ADD             0000 11 . ..... ....        @op_rd_rr
> +ADC             0001 11 . ..... ....        @op_rd_rr
> +AND             0010 00 . ..... ....        @op_rd_rr
> +CP              0001 01 . ..... ....        @op_rd_rr
> +CPC             0000 01 . ..... ....        @op_rd_rr
> +CPSE            0001 00 . ..... ....        @op_rd_rr
> +EOR             0010 01 . ..... ....        @op_rd_rr
> +MOV             0010 11 . ..... ....        @op_rd_rr
> +MUL             1001 11 . ..... ....        @op_rd_rr
> +OR              0010 10 . ..... ....        @op_rd_rr
> +SBC             0000 10 . ..... ....        @op_rd_rr
> +SUB             0001 10 . ..... ....        @op_rd_rr
> +
> +
> +%rd_c           4:2                         !function=to_regs_24_30_by_two
> +%imm6           6:2 0:4
> +
> +@op_rd_imm6     .... .... .. .. ....        &rd_imm     rd=%rd_c imm=%imm6
> +ADIW            1001 0110 .. .. ....        @op_rd_imm6
> +SBIW            1001 0111 .. .. ....        @op_rd_imm6
> +
> +
> +%rd_a           4:4                         !function=to_regs_16_31_by_one
> +%rr_a           0:4                         !function=to_regs_16_31_by_one
> +%rd_d           4:4                         !function=to_regs_00_30_by_two
> +%rr_d           0:4                         !function=to_regs_00_30_by_two
> +%imm8           8:4 0:4
> +
> +@op_rd_imm8     .... .... .... ....         &rd_imm     rd=%rd_a imm=%imm8
> +ANDI            0111 .... .... ....         @op_rd_imm8
> +CPI             0011 .... .... ....         @op_rd_imm8
> +LDI             1110 .... .... ....         @op_rd_imm8
> +ORI             0110 .... .... ....         @op_rd_imm8
> +SBCI            0100 .... .... ....         @op_rd_imm8
> +SUBI            0101 .... .... ....         @op_rd_imm8
> +
> +
> +@op_rd          .... ... rd:5 ....
> +ASR             1001 010 ..... 0101         @op_rd
> +COM             1001 010 ..... 0000         @op_rd
> +DEC             1001 010 ..... 1010         @op_rd
> +ELPM2           1001 000 ..... 0110         @op_rd
> +ELPMX           1001 000 ..... 0111         @op_rd
> +INC             1001 010 ..... 0011         @op_rd
> +LDX1            1001 000 ..... 1100         @op_rd
> +LDX2            1001 000 ..... 1101         @op_rd
> +LDX3            1001 000 ..... 1110         @op_rd
> +LDY2            1001 000 ..... 1001         @op_rd
> +LDY3            1001 000 ..... 1010         @op_rd
> +LDZ2            1001 000 ..... 0001         @op_rd
> +LDZ3            1001 000 ..... 0010         @op_rd
> +LPM2            1001 000 ..... 0100         @op_rd
> +LPMX            1001 000 ..... 0101         @op_rd
> +LSR             1001 010 ..... 0110         @op_rd
> +NEG             1001 010 ..... 0001         @op_rd
> +POP             1001 000 ..... 1111         @op_rd
> +PUSH            1001 001 ..... 1111         @op_rd
> +ROR             1001 010 ..... 0111         @op_rd
> +STY2            1001 001 ..... 1001         @op_rd
> +STY3            1001 001 ..... 1010         @op_rd
> +STZ2            1001 001 ..... 0001         @op_rd
> +STZ3            1001 001 ..... 0010         @op_rd
> +SWAP            1001 010 ..... 0010         @op_rd
> +
> +
> +@op_bit         .... .... . bit:3 ....
> +BCLR            1001 0100 1 ... 1000        @op_bit
> +BSET            1001 0100 0 ... 1000        @op_bit
> +
> +
> +@op_rd_bit      .... ... rd:5 . bit:3
> +BLD             1111 100 ..... 0 ...        @op_rd_bit
> +BST             1111 101 ..... 0 ...        @op_rd_bit
> +
> +
> +@op_bit_imm     .... .. imm:s7 bit:3
> +BRBC            1111 01 ....... ...         @op_bit_imm
> +BRBS            1111 00 ....... ...         @op_bit_imm
> +
> +
> +BREAK           1001 0101 1001 1000
> +EICALL          1001 0101 0001 1001
> +EIJMP           1001 0100 0001 1001
> +ELPM1           1001 0101 1101 1000
> +ICALL           1001 0101 0000 1001
> +IJMP            1001 0100 0000 1001
> +LPM1            1001 0101 1100 1000
> +NOP             0000 0000 0000 0000
> +RET             1001 0101 0000 1000
> +RETI            1001 0101 0001 1000
> +SLEEP           1001 0101 1000 1000
> +SPM             1001 0101 1110 1000
> +SPMX            1001 0101 1111 1000
> +WDR             1001 0101 1010 1000
> +
> +
> +@op_reg_bit     .... .... reg:5 bit:3
> +CBI             1001 1000 ..... ...         @op_reg_bit
> +SBI             1001 1010 ..... ...         @op_reg_bit
> +SBIC            1001 1001 ..... ...         @op_reg_bit
> +SBIS            1001 1011 ..... ...         @op_reg_bit
> +
> +
> +DES             1001 0100 imm:4 1011
> +
> +
> +%rd_b           4:3                         !function=to_regs_16_23_by_one
> +%rr_b           0:3                         !function=to_regs_16_23_by_one
> +@fmul           .... .... . ... . ...       &rd_rr      rd=%rd_b rr=%rr_b
> +FMUL            0000 0011 0 ... 1 ...       @fmul
> +FMULS           0000 0011 1 ... 0 ...       @fmul
> +FMULSU          0000 0011 1 ... 1 ...       @fmul
> +MULSU           0000 0011 0 ... 0 ...       @fmul
> +
> +
> +%io_imm         9:2 0:4
> +@io_rd_imm      .... . .. ..... ....        &rd_imm     rd=%rd imm=%io_imm
> +IN              1011 0 .. ..... ....        @io_rd_imm
> +OUT             1011 1 .. ..... ....        @io_rd_imm
> +
> +
> +XCH             1001 001 rd:5 0100
> +LAC             1001 001 rd:5 0110
> +LAS             1001 001 rd:5 0101
> +LAT             1001 001 rd:5 0111
> +STX1            1001 001 rr:5 1100
> +STX2            1001 001 rr:5 1101
> +STX3            1001 001 rr:5 1110
> +
> +
> +%ldst_d_imm     13:1 10:2 0:3
> +@ldst_d         .. . . .. . rd:5  . ...     &rd_imm     imm=%ldst_d_imm
> +LDDY            10 . 0 .. 0 ..... 1 ...     @ldst_d
> +LDDZ            10 . 0 .. 0 ..... 0 ...     @ldst_d
> +STDY            10 . 0 .. 1 ..... 1 ...     @ldst_d
> +STDZ            10 . 0 .. 1 ..... 0 ...     @ldst_d
> +
> +
> +MOVW            0000 0001 .... ....         &rd_rr      rd=%rd_d rr=%rr_d
> +MULS            0000 0010 .... ....         &rd_rr      rd=%rd_a rr=%rr_a
> +
> +RCALL           1101 imm:s12
> +RJMP            1100 imm:s12
> +
> +SBRC            1111 110 rr:5 0 bit:3
> +SBRS            1111 111 rr:5 0 bit:3
> +
> +# The 22-bit immediate is partially in the opcode word,
> +# and partially in the next.  Use append_16 to build the
> +# complete 22-bit value.
> +%imm_call       4:5 0:1                     !function=append_16
> +CALL            1001 010 ..... 111 .        imm=%imm_call
> +JMP             1001 010 ..... 110 .        imm=%imm_call
> +
> +
> +# The 16-bit immediate is completely in the next word.
> +# Fields cannot be defined with no bits, so we cannot play
> +# the same trick and append to a zero-bit value.
> +# Defer reading the immediate until trans_{LDS,STS}.
> +@ldst_s         .... ... rd:5 ....          imm=0
> +LDS             1001 000 ..... 0000         @ldst_s
> +STS             1001 001 ..... 0000         @ldst_s
> --
> 2.17.2 (Apple Git-113)
>
>
Aleksandar Markovic Dec. 9, 2019, 7:44 p.m. UTC | #2
On Monday, December 9, 2019, Aleksandar Markovic <
aleksandar.m.mail@gmail.com> wrote:

>
>
> On Sunday, December 8, 2019, Michael Rolnik <mrolnik@gmail.com> wrote:
>
>> This includes:
>> - encoding of all 16 bit instructions
>> - encoding of all 32 bit instructions
>>
>> Signed-off-by: Michael Rolnik <mrolnik@gmail.com>
>> Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
>> ---
>>  target/avr/insn.decode | 194 +++++++++++++++++++++++++++++++++++++++++
>>  1 file changed, 194 insertions(+)
>>  create mode 100644 target/avr/insn.decode
>>
>>
> Hi, Michael,
>
> Could you please reorder decoding definitions in this file following this
> pattern:
>
> #
> # Arithmetic Instructions
> #
>
> < their decoding definitions in the order they appear in the ISA doc >
>
> #
> target/avr: Add instruction translation - Branch Instructions
> #
>

copu-paste error. I meant:


# Branch Instructions
>
#
>

If you refactor the file this way, it will be much easier to inspect the
code, and also to add changes in case of future versions of AVR ISA - the
file would look much tidier.

Take care,
Aleksandar


> < their decoding definitions in the order they appear in the ISA doc >
>
> #
> # Data Transfer Instructions
> #
>
> < their decoding definitions in the order they appear in the ISA doc >
>
> #
> # Bit and Bit-test Instructions
> #
>
> < their decoding definitions in the order they appear in the ISA doc >
>
> #
> # MCU Control Instructions
> #
>
> < their decoding definitions in the order they appear in the ISA doc >
>
>
>
> Thanks in advance!
>
> Aleksandar
>
>
>
>
>
>
>> diff --git a/target/avr/insn.decode b/target/avr/insn.decode
>> new file mode 100644
>> index 0000000000..2eb6de692a
>> --- /dev/null
>> +++ b/target/avr/insn.decode
>> @@ -0,0 +1,194 @@
>> +#
>> +# AVR instruction decode definitions.
>> +#
>> +# Copyright (c) 2019 Michael Rolnik <mrolnik@gmail.com>
>> +#
>> +# This library is free software; you can redistribute it and/or
>> +# modify it under the terms of the GNU Lesser General Public
>> +# License as published by the Free Software Foundation; either
>> +# version 2.1 of the License, or (at your option) any later version.
>> +#
>> +# This library is distributed in the hope that it will be useful,
>> +# but WITHOUT ANY WARRANTY; without even the implied warranty of
>> +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
>> +# Lesser General Public License for more details.
>> +#
>> +# You should have received a copy of the GNU Lesser General Public
>> +# License along with this library; if not, see <
>> http://www.gnu.org/licenses/>.
>> +#
>> +
>> +#
>> +#   regs_16_31_by_one = [16 .. 31]
>> +#   regs_16_23_by_one = [16 .. 23]
>> +#   regs_24_30_by_two = [24, 26, 28, 30]
>> +#   regs_00_30_by_two = [0, 2, 4, 6, 8, .. 30]
>> +
>> +%rd             4:5
>> +%rr             9:1 0:4
>> +
>> +&rd_rr          rd rr
>> +&rd_imm         rd imm
>> +
>> +@op_rd_rr       .... .. . ..... ....        &rd_rr      rd=%rd rr=%rr
>> +ADD             0000 11 . ..... ....        @op_rd_rr
>> +ADC             0001 11 . ..... ....        @op_rd_rr
>> +AND             0010 00 . ..... ....        @op_rd_rr
>> +CP              0001 01 . ..... ....        @op_rd_rr
>> +CPC             0000 01 . ..... ....        @op_rd_rr
>> +CPSE            0001 00 . ..... ....        @op_rd_rr
>> +EOR             0010 01 . ..... ....        @op_rd_rr
>> +MOV             0010 11 . ..... ....        @op_rd_rr
>> +MUL             1001 11 . ..... ....        @op_rd_rr
>> +OR              0010 10 . ..... ....        @op_rd_rr
>> +SBC             0000 10 . ..... ....        @op_rd_rr
>> +SUB             0001 10 . ..... ....        @op_rd_rr
>> +
>> +
>> +%rd_c           4:2                         !function=to_regs_24_30_by_
>> two
>> +%imm6           6:2 0:4
>> +
>> +@op_rd_imm6     .... .... .. .. ....        &rd_imm     rd=%rd_c
>> imm=%imm6
>> +ADIW            1001 0110 .. .. ....        @op_rd_imm6
>> +SBIW            1001 0111 .. .. ....        @op_rd_imm6
>> +
>> +
>> +%rd_a           4:4                         !function=to_regs_16_31_by_
>> one
>> +%rr_a           0:4                         !function=to_regs_16_31_by_
>> one
>> +%rd_d           4:4                         !function=to_regs_00_30_by_
>> two
>> +%rr_d           0:4                         !function=to_regs_00_30_by_
>> two
>> +%imm8           8:4 0:4
>> +
>> +@op_rd_imm8     .... .... .... ....         &rd_imm     rd=%rd_a
>> imm=%imm8
>> +ANDI            0111 .... .... ....         @op_rd_imm8
>> +CPI             0011 .... .... ....         @op_rd_imm8
>> +LDI             1110 .... .... ....         @op_rd_imm8
>> +ORI             0110 .... .... ....         @op_rd_imm8
>> +SBCI            0100 .... .... ....         @op_rd_imm8
>> +SUBI            0101 .... .... ....         @op_rd_imm8
>> +
>> +
>> +@op_rd          .... ... rd:5 ....
>> +ASR             1001 010 ..... 0101         @op_rd
>> +COM             1001 010 ..... 0000         @op_rd
>> +DEC             1001 010 ..... 1010         @op_rd
>> +ELPM2           1001 000 ..... 0110         @op_rd
>> +ELPMX           1001 000 ..... 0111         @op_rd
>> +INC             1001 010 ..... 0011         @op_rd
>> +LDX1            1001 000 ..... 1100         @op_rd
>> +LDX2            1001 000 ..... 1101         @op_rd
>> +LDX3            1001 000 ..... 1110         @op_rd
>> +LDY2            1001 000 ..... 1001         @op_rd
>> +LDY3            1001 000 ..... 1010         @op_rd
>> +LDZ2            1001 000 ..... 0001         @op_rd
>> +LDZ3            1001 000 ..... 0010         @op_rd
>> +LPM2            1001 000 ..... 0100         @op_rd
>> +LPMX            1001 000 ..... 0101         @op_rd
>> +LSR             1001 010 ..... 0110         @op_rd
>> +NEG             1001 010 ..... 0001         @op_rd
>> +POP             1001 000 ..... 1111         @op_rd
>> +PUSH            1001 001 ..... 1111         @op_rd
>> +ROR             1001 010 ..... 0111         @op_rd
>> +STY2            1001 001 ..... 1001         @op_rd
>> +STY3            1001 001 ..... 1010         @op_rd
>> +STZ2            1001 001 ..... 0001         @op_rd
>> +STZ3            1001 001 ..... 0010         @op_rd
>> +SWAP            1001 010 ..... 0010         @op_rd
>> +
>> +
>> +@op_bit         .... .... . bit:3 ....
>> +BCLR            1001 0100 1 ... 1000        @op_bit
>> +BSET            1001 0100 0 ... 1000        @op_bit
>> +
>> +
>> +@op_rd_bit      .... ... rd:5 . bit:3
>> +BLD             1111 100 ..... 0 ...        @op_rd_bit
>> +BST             1111 101 ..... 0 ...        @op_rd_bit
>> +
>> +
>> +@op_bit_imm     .... .. imm:s7 bit:3
>> +BRBC            1111 01 ....... ...         @op_bit_imm
>> +BRBS            1111 00 ....... ...         @op_bit_imm
>> +
>> +
>> +BREAK           1001 0101 1001 1000
>> +EICALL          1001 0101 0001 1001
>> +EIJMP           1001 0100 0001 1001
>> +ELPM1           1001 0101 1101 1000
>> +ICALL           1001 0101 0000 1001
>> +IJMP            1001 0100 0000 1001
>> +LPM1            1001 0101 1100 1000
>> +NOP             0000 0000 0000 0000
>> +RET             1001 0101 0000 1000
>> +RETI            1001 0101 0001 1000
>> +SLEEP           1001 0101 1000 1000
>> +SPM             1001 0101 1110 1000
>> +SPMX            1001 0101 1111 1000
>> +WDR             1001 0101 1010 1000
>> +
>> +
>> +@op_reg_bit     .... .... reg:5 bit:3
>> +CBI             1001 1000 ..... ...         @op_reg_bit
>> +SBI             1001 1010 ..... ...         @op_reg_bit
>> +SBIC            1001 1001 ..... ...         @op_reg_bit
>> +SBIS            1001 1011 ..... ...         @op_reg_bit
>> +
>> +
>> +DES             1001 0100 imm:4 1011
>> +
>> +
>> +%rd_b           4:3                         !function=to_regs_16_23_by_
>> one
>> +%rr_b           0:3                         !function=to_regs_16_23_by_
>> one
>> +@fmul           .... .... . ... . ...       &rd_rr      rd=%rd_b rr=%rr_b
>> +FMUL            0000 0011 0 ... 1 ...       @fmul
>> +FMULS           0000 0011 1 ... 0 ...       @fmul
>> +FMULSU          0000 0011 1 ... 1 ...       @fmul
>> +MULSU           0000 0011 0 ... 0 ...       @fmul
>> +
>> +
>> +%io_imm         9:2 0:4
>> +@io_rd_imm      .... . .. ..... ....        &rd_imm     rd=%rd
>> imm=%io_imm
>> +IN              1011 0 .. ..... ....        @io_rd_imm
>> +OUT             1011 1 .. ..... ....        @io_rd_imm
>> +
>> +
>> +XCH             1001 001 rd:5 0100
>> +LAC             1001 001 rd:5 0110
>> +LAS             1001 001 rd:5 0101
>> +LAT             1001 001 rd:5 0111
>> +STX1            1001 001 rr:5 1100
>> +STX2            1001 001 rr:5 1101
>> +STX3            1001 001 rr:5 1110
>> +
>> +
>> +%ldst_d_imm     13:1 10:2 0:3
>> +@ldst_d         .. . . .. . rd:5  . ...     &rd_imm     imm=%ldst_d_imm
>> +LDDY            10 . 0 .. 0 ..... 1 ...     @ldst_d
>> +LDDZ            10 . 0 .. 0 ..... 0 ...     @ldst_d
>> +STDY            10 . 0 .. 1 ..... 1 ...     @ldst_d
>> +STDZ            10 . 0 .. 1 ..... 0 ...     @ldst_d
>> +
>> +
>> +MOVW            0000 0001 .... ....         &rd_rr      rd=%rd_d rr=%rr_d
>> +MULS            0000 0010 .... ....         &rd_rr      rd=%rd_a rr=%rr_a
>> +
>> +RCALL           1101 imm:s12
>> +RJMP            1100 imm:s12
>> +
>> +SBRC            1111 110 rr:5 0 bit:3
>> +SBRS            1111 111 rr:5 0 bit:3
>> +
>> +# The 22-bit immediate is partially in the opcode word,
>> +# and partially in the next.  Use append_16 to build the
>> +# complete 22-bit value.
>> +%imm_call       4:5 0:1                     !function=append_16
>> +CALL            1001 010 ..... 111 .        imm=%imm_call
>> +JMP             1001 010 ..... 110 .        imm=%imm_call
>> +
>> +
>> +# The 16-bit immediate is completely in the next word.
>> +# Fields cannot be defined with no bits, so we cannot play
>> +# the same trick and append to a zero-bit value.
>> +# Defer reading the immediate until trans_{LDS,STS}.
>> +@ldst_s         .... ... rd:5 ....          imm=0
>> +LDS             1001 000 ..... 0000         @ldst_s
>> +STS             1001 001 ..... 0000         @ldst_s
>> --
>> 2.17.2 (Apple Git-113)
>>
>>
diff mbox series

Patch

diff --git a/target/avr/insn.decode b/target/avr/insn.decode
new file mode 100644
index 0000000000..2eb6de692a
--- /dev/null
+++ b/target/avr/insn.decode
@@ -0,0 +1,194 @@ 
+#
+# AVR instruction decode definitions.
+#
+# Copyright (c) 2019 Michael Rolnik <mrolnik@gmail.com>
+#
+# This library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2.1 of the License, or (at your option) any later version.
+#
+# This library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with this library; if not, see <http://www.gnu.org/licenses/>.
+#
+
+#
+#   regs_16_31_by_one = [16 .. 31]
+#   regs_16_23_by_one = [16 .. 23]
+#   regs_24_30_by_two = [24, 26, 28, 30]
+#   regs_00_30_by_two = [0, 2, 4, 6, 8, .. 30]
+
+%rd             4:5
+%rr             9:1 0:4
+
+&rd_rr          rd rr
+&rd_imm         rd imm
+
+@op_rd_rr       .... .. . ..... ....        &rd_rr      rd=%rd rr=%rr
+ADD             0000 11 . ..... ....        @op_rd_rr
+ADC             0001 11 . ..... ....        @op_rd_rr
+AND             0010 00 . ..... ....        @op_rd_rr
+CP              0001 01 . ..... ....        @op_rd_rr
+CPC             0000 01 . ..... ....        @op_rd_rr
+CPSE            0001 00 . ..... ....        @op_rd_rr
+EOR             0010 01 . ..... ....        @op_rd_rr
+MOV             0010 11 . ..... ....        @op_rd_rr
+MUL             1001 11 . ..... ....        @op_rd_rr
+OR              0010 10 . ..... ....        @op_rd_rr
+SBC             0000 10 . ..... ....        @op_rd_rr
+SUB             0001 10 . ..... ....        @op_rd_rr
+
+
+%rd_c           4:2                         !function=to_regs_24_30_by_two
+%imm6           6:2 0:4
+
+@op_rd_imm6     .... .... .. .. ....        &rd_imm     rd=%rd_c imm=%imm6
+ADIW            1001 0110 .. .. ....        @op_rd_imm6
+SBIW            1001 0111 .. .. ....        @op_rd_imm6
+
+
+%rd_a           4:4                         !function=to_regs_16_31_by_one
+%rr_a           0:4                         !function=to_regs_16_31_by_one
+%rd_d           4:4                         !function=to_regs_00_30_by_two
+%rr_d           0:4                         !function=to_regs_00_30_by_two
+%imm8           8:4 0:4
+
+@op_rd_imm8     .... .... .... ....         &rd_imm     rd=%rd_a imm=%imm8
+ANDI            0111 .... .... ....         @op_rd_imm8
+CPI             0011 .... .... ....         @op_rd_imm8
+LDI             1110 .... .... ....         @op_rd_imm8
+ORI             0110 .... .... ....         @op_rd_imm8
+SBCI            0100 .... .... ....         @op_rd_imm8
+SUBI            0101 .... .... ....         @op_rd_imm8
+
+
+@op_rd          .... ... rd:5 ....
+ASR             1001 010 ..... 0101         @op_rd
+COM             1001 010 ..... 0000         @op_rd
+DEC             1001 010 ..... 1010         @op_rd
+ELPM2           1001 000 ..... 0110         @op_rd
+ELPMX           1001 000 ..... 0111         @op_rd
+INC             1001 010 ..... 0011         @op_rd
+LDX1            1001 000 ..... 1100         @op_rd
+LDX2            1001 000 ..... 1101         @op_rd
+LDX3            1001 000 ..... 1110         @op_rd
+LDY2            1001 000 ..... 1001         @op_rd
+LDY3            1001 000 ..... 1010         @op_rd
+LDZ2            1001 000 ..... 0001         @op_rd
+LDZ3            1001 000 ..... 0010         @op_rd
+LPM2            1001 000 ..... 0100         @op_rd
+LPMX            1001 000 ..... 0101         @op_rd
+LSR             1001 010 ..... 0110         @op_rd
+NEG             1001 010 ..... 0001         @op_rd
+POP             1001 000 ..... 1111         @op_rd
+PUSH            1001 001 ..... 1111         @op_rd
+ROR             1001 010 ..... 0111         @op_rd
+STY2            1001 001 ..... 1001         @op_rd
+STY3            1001 001 ..... 1010         @op_rd
+STZ2            1001 001 ..... 0001         @op_rd
+STZ3            1001 001 ..... 0010         @op_rd
+SWAP            1001 010 ..... 0010         @op_rd
+
+
+@op_bit         .... .... . bit:3 ....
+BCLR            1001 0100 1 ... 1000        @op_bit
+BSET            1001 0100 0 ... 1000        @op_bit
+
+
+@op_rd_bit      .... ... rd:5 . bit:3
+BLD             1111 100 ..... 0 ...        @op_rd_bit
+BST             1111 101 ..... 0 ...        @op_rd_bit
+
+
+@op_bit_imm     .... .. imm:s7 bit:3
+BRBC            1111 01 ....... ...         @op_bit_imm
+BRBS            1111 00 ....... ...         @op_bit_imm
+
+
+BREAK           1001 0101 1001 1000
+EICALL          1001 0101 0001 1001
+EIJMP           1001 0100 0001 1001
+ELPM1           1001 0101 1101 1000
+ICALL           1001 0101 0000 1001
+IJMP            1001 0100 0000 1001
+LPM1            1001 0101 1100 1000
+NOP             0000 0000 0000 0000
+RET             1001 0101 0000 1000
+RETI            1001 0101 0001 1000
+SLEEP           1001 0101 1000 1000
+SPM             1001 0101 1110 1000
+SPMX            1001 0101 1111 1000
+WDR             1001 0101 1010 1000
+
+
+@op_reg_bit     .... .... reg:5 bit:3
+CBI             1001 1000 ..... ...         @op_reg_bit
+SBI             1001 1010 ..... ...         @op_reg_bit
+SBIC            1001 1001 ..... ...         @op_reg_bit
+SBIS            1001 1011 ..... ...         @op_reg_bit
+
+
+DES             1001 0100 imm:4 1011
+
+
+%rd_b           4:3                         !function=to_regs_16_23_by_one
+%rr_b           0:3                         !function=to_regs_16_23_by_one
+@fmul           .... .... . ... . ...       &rd_rr      rd=%rd_b rr=%rr_b
+FMUL            0000 0011 0 ... 1 ...       @fmul
+FMULS           0000 0011 1 ... 0 ...       @fmul
+FMULSU          0000 0011 1 ... 1 ...       @fmul
+MULSU           0000 0011 0 ... 0 ...       @fmul
+
+
+%io_imm         9:2 0:4
+@io_rd_imm      .... . .. ..... ....        &rd_imm     rd=%rd imm=%io_imm
+IN              1011 0 .. ..... ....        @io_rd_imm
+OUT             1011 1 .. ..... ....        @io_rd_imm
+
+
+XCH             1001 001 rd:5 0100
+LAC             1001 001 rd:5 0110
+LAS             1001 001 rd:5 0101
+LAT             1001 001 rd:5 0111
+STX1            1001 001 rr:5 1100
+STX2            1001 001 rr:5 1101
+STX3            1001 001 rr:5 1110
+
+
+%ldst_d_imm     13:1 10:2 0:3
+@ldst_d         .. . . .. . rd:5  . ...     &rd_imm     imm=%ldst_d_imm
+LDDY            10 . 0 .. 0 ..... 1 ...     @ldst_d
+LDDZ            10 . 0 .. 0 ..... 0 ...     @ldst_d
+STDY            10 . 0 .. 1 ..... 1 ...     @ldst_d
+STDZ            10 . 0 .. 1 ..... 0 ...     @ldst_d
+
+
+MOVW            0000 0001 .... ....         &rd_rr      rd=%rd_d rr=%rr_d
+MULS            0000 0010 .... ....         &rd_rr      rd=%rd_a rr=%rr_a
+
+RCALL           1101 imm:s12
+RJMP            1100 imm:s12
+
+SBRC            1111 110 rr:5 0 bit:3
+SBRS            1111 111 rr:5 0 bit:3
+
+# The 22-bit immediate is partially in the opcode word,
+# and partially in the next.  Use append_16 to build the
+# complete 22-bit value.
+%imm_call       4:5 0:1                     !function=append_16
+CALL            1001 010 ..... 111 .        imm=%imm_call
+JMP             1001 010 ..... 110 .        imm=%imm_call
+
+
+# The 16-bit immediate is completely in the next word.
+# Fields cannot be defined with no bits, so we cannot play
+# the same trick and append to a zero-bit value.
+# Defer reading the immediate until trans_{LDS,STS}.
+@ldst_s         .... ... rd:5 ....          imm=0
+LDS             1001 000 ..... 0000         @ldst_s
+STS             1001 001 ..... 0000         @ldst_s