Re: [PATCH v37 00/17] QEMU AVR 8 bit cores

[Michael Rolnik <mrolnik@gmail.com>]

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On Wed, Nov 27, 2019 at 11:06 PM Aleksandar Markovic <
aleksandar.m.mail@gmail.com> wrote:

> On Wed, Nov 27, 2019 at 6:53 PM Michael Rolnik <mrolnik@gmail.com> wrote:
> >
> > This series of patches adds 8bit AVR cores to QEMU.
> > All instruction, except BREAK/DES/SPM/SPMX, are implemented. Not fully
> tested yet.
> > However I was able to execute simple code with functions. e.g fibonacci
> calculation.
> > This series of patches include a non real, sample board.
> > No fuses support yet. PC is set to 0 at reset.
> >
>
> I have a couple of general remarks, so I am responding to the cover
> letter, not individual patches.
>
> 1) The licenses for Sarah devices differ than the rest - shouldn't all
> licenses be harmonized?

Sarah,
do you mind if use the same license I use for my code?


>


> 2) There is an architectural problem with peripherals. It is possible
> that they evolve over time, so, for example, USART could not be the
> same for older and newer CPUs (in principle, newer peripheral is
> expected to be o sort of "superset" of the older). How do you solve
> that problem? Right now, it may not looks serious to you, but if you
> don;t think about that right now, from the outset, soon the code will
> become so entangled, ti woudl be almost very difficult to fix it.
> Please think about that, how would you solve it, is there a way to
> pass the information on the currently emulated CPU to the code
> covering a peripheral, and provide a different behaviour?
>
Hi Aleksandar,

Please explain. I don't see any problem from CPU's perspective.
as for the sample board is just a sample, I hope other people will create
real models or real hw.
there was no way I could provide a CPU alone, that's why there is sample.



>
> > Following are examples of possible usages, assuming program.elf is
> compiled for AVR cpu
> > 1.  Continious non interrupted execution
> >     run `qemu-system-avr -kernel program.elf`
> > 2.  Continious non interrupted execution with serial output into telnet
> window
> >     run `qemu-system-avr -kernel program.elf -serial
> tcp::5678,server,nowait -nographic `
> >     run `telent localhost 5678`
> > 3.  Continious non interrupted execution with serial output into stdout
> >     run `qemu-system-avr -kernel program.elf -serial stdio`
> > 4.  Debugging wit GDB debugger
> >     run `qemu-system-avr -kernel program.elf -s -S`
> >     run `avr-gdb program.elf` and then within GDB shell `target remote
> :1234`
> > 5.  Print out executed instructions
> >     run `qemu-system-avr -kernel program.elf -d in_asm`
> >
>
> Thank you so much for these examples!
>
> Aleksandar
>
>
> >
> > the patches include the following
> > 1. just a basic 8bit AVR CPU, without instruction decoding or translation
> > 2. CPU features which allow define the following 8bit AVR cores
> >      avr1
> >      avr2 avr25
> >      avr3 avr31 avr35
> >      avr4
> >      avr5 avr51
> >      avr6
> >      xmega2 xmega4 xmega5 xmega6 xmega7
> > 3. a definition of sample machine with SRAM, FLASH and CPU which allows
> to execute simple code
> > 4. encoding for all AVR instructions
> > 5. interrupt handling
> > 6. helpers for IN, OUT, SLEEP, WBR & unsupported instructions
> > 7. a decoder which given an opcode decides what istruction it is
> > 8. translation of AVR instruction into TCG
> > 9. all features together
> >
> > changes since v3
> > 1. rampD/X/Y/Z registers are encoded as 0x00ff0000 (instead of
> 0x000000ff) for faster address manipulaton
> > 2. ffs changed to ctz32
> > 3. duplicate code removed at avr_cpu_do_interrupt
> > 4. using andc instead of not + and
> > 5. fixing V flag calculation in varios instructions
> > 6. freeing local variables in PUSH
> > 7. tcg_const_local_i32 -> tcg_const_i32
> > 8. using sextract32 instead of my implementation
> > 9. fixing BLD instruction
> > 10.xor(r) instead of 0xff - r at COM
> > 11.fixing MULS/MULSU not to modify inputs' content
> > 12.using SUB for NEG
> > 13.fixing tcg_gen_qemu_ld/st call in XCH
> >
> > changes since v4
> > 1. target is now defined as big endian in order to optimize
> push_ret/pop_ret
> > 2. all style warnings are fixed
> > 3. adding cpu_set/get_sreg functions
> > 4. simplifying gen_goto_tb as there is no real paging
> > 5. env->pc -> env->pc_w
> > 6. making flag dump more compact
> > 7. more spacing
> > 8. renaming CODE/DATA_INDEX -> MMU_CODE/DATA_IDX
> > 9. removing avr_set_feature
> > 10. SPL/SPH set bug fix
> > 11. switching stb_phys to cpu_stb_data
> > 12. cleaning up avr_decode
> > 13. saving sreg, rampD/X/Y/Z, eind in HW format (savevm)
> > 14. saving CPU features (savevm)
> >
> > changes since v5
> > 1. BLD bug fix
> > 2. decoder generator is added
> >
> > chages since v6
> > 1. using cpu_get_sreg/cpu_set_sreg in
> avr_cpu_gdb_read_register/avr_cpu_gdb_write_register
> > 2. configure the target as little endian because otherwise GDB does not
> work
> > 3. fixing and testing gen_push_ret/gen_pop_ret
> >
> > changes since v7
> > 1. folding back v6
> > 2. logging at helper_outb and helper_inb are done for non supported yet
> registers only
> > 3. MAINTAINERS updated
> >
> > changes since v8
> > 1. removing hw/avr from hw/Makefile.obj as it should not be built for all
> > 2. making linux compilable
> > 3. testing on
> >     a. Mac, Apple LLVM version 7.0.0
> >     b. Ubuntu 12.04, gcc 4.9.2
> >     c. Fedora 23, gcc 5.3.1
> > 4. folding back some patches
> > 5. translation bug fixes for ORI, CPI, XOR instructions
> > 6. propper handling of cpu register writes though memory
> >
> > changes since v9
> > 1. removing forward declarations of static functions
> > 2. disabling debug prints
> > 3. switching to case range instead of if else if ...
> > 4. LD/ST IN/OUT accessing CPU maintainder registers are not routed to
> any device
> > 5. commenst about sample board and sample IO device added
> > 6. sample board description is more descriptive now
> > 7. memory_region_allocate_system_memory is used to create RAM
> > 8. now there are helper_fullrd & helper_fullwr when LD/ST try to access
> registers
> >
> > changes since v10
> > 1. movig back fullwr & fullrd into the commit where outb and inb were
> introduced
> > 2. changing tlb_fill function signature
> > 3. adding empty line between functions
> > 4. adding newline on the last line of the file
> > 5. using tb->flags to generae full access ST/LD instructions
> > 6. fixing SBRC bug
> > 7. folding back 10th commit
> > 8. whenever a new file is introduced it's added to Makefile.objs
> >
> > changes since v11
> > 1. updating to v2.7.0-rc
> > 2. removing assignment to env->fullacc from gen_intermediate_code
> >
> > changes since v12
> > 1. fixing spacing
> > 2. fixing get/put_segment functions
> > 3. removing target-avr/machine.h file
> > 4. VMSTATE_SINGLE_TEST -> VMSTATE_SINGLE
> > 5. comment spelling
> > 6. removing hw/avr/sample_io.c
> > 7. char const* -> const char*
> > 8. proper ram allocation
> > 9. fixing breakpoint functionality.
> > 10.env1 -> env
> > 11.fixing avr_cpu_gdb_write_register & avr_cpu_gdb_read_register
> functions
> > 12.any cpu is removed
> > 12.feature bits are not saved into vm state
> >
> > changes since v13
> > 1. rebasing to v2.7.0-rc1
> >
> > changes since v14
> > 1. I made self review with git gui tool. (I did not know such a thing
> exists)
> > 2. removing all double/tripple spaces
> > 3. removing comment reference to SampleIO
> > 4. folding back some changes, so there is not deleted lines in my code
> > 5. moving avr configuration, within configure file, before chris
> >
> > changes since v15
> > 1. removing IO registers cache from CPU
> > 2. implementing CBI/SBI as read(helper_inb), modify, write(helper_outb)
> > 3. implementing CBIC/SBIC as read(helper_inb), check, branch
> > 4. adding missing tcg_temp_free_i32 for tcg_const_i32
> >
> > changes since v16
> > 1. removing EXT IO registers knoledge from CPU. These registers are
> accessible
> >    by LD/ST only. CPU has no interest in them
> >
> > changes since v17 (by Richard Henderson)
> > This is Michael's v17, with some adjustments of my own:
> >
> > 1. Fix the whitespace errors reported by "git am",
> > 2. Replace the utf-8 characters with normal ascii,
> > 3. Ditch the separate compilation of translate.c.
> >
> > I retained the two separate files that could be regenerated
> > from the included cpugen program, but merged in translate-insn.c.
> > Not that it matters, but the code generated is about 3k smaller.
> >
> > changes since v18
> > 1.  moving target-avr into target/avr
> > 2.  do not call cpu_exec_initfn function from avr_cpu_initfn
> > 3.  call cpu_exec_realizefn avr_cpu_realizefn
> > 4.  do not fail sample machine creation if no rom is suplied
> > 5.  add tcg_gen_exit_tb(0) for BS_BRANCH in gen_intermediate_code
> > 6.  fix a register getters/setters in machine.c
> > 7.  changing QEMU_ARCH_AVR from 1<<17 to 1<<18
> >
> > changes since v19
> > 1.  use decodetree.py tool to decode instructions
> > 2.  adding USART
> > 3.  adding 16 bit timer peripherals
> > 4.  changing QEMU_ARCH_AVR from 1<<18 to 1<<20
> > 5.  renaming tlb_fill to avr_cpu_tlb_fill
> >
> > changes since v20
> > 1.  use one CPU naming convention
> > 2.  merging insn16.decode & insn32.decode files
> > 3.  modifying skip next instruction mechanizm
> > 4.  translate BREAK as NOP for now
> >
> > changes since v21
> > 1.  Reorganize bstate.
> >     This will make transition to <exec/translator.h> easier, and fixes a
> couple of bugs wrt single stepping
> >     by richard.henderson@linaro.org
> > 2.  Drop cpc and fix page cross condition.
> >     by richard.henderson@linaro.org
> > 3.  Refactor checking supported/unsupported instructions
> > 4.  Add gdb-xml/avr-cpu.xml
> >
> > changes since v22
> > 1.  Rebase
> > 2.  Split long comment
> >
> > changes since v23
> > 1.  remove avr_cpu_list_compare function
> > 2.  modify avr_cpu_class_by_name function
> > 3.  modify avr_cpu_list_entry function
> > 4.  modify avr_cpu_list function
> >
> > changes since v24
> > 1.  remove AVR_CPU_TYPE_NAME macro
> >
> > changes since v25
> > 1.  fix patches. every file belong to one patch only
> > 2.  change copyright year from 2016 to 2019
> > 3.  create mask device to emulate prr0/prr1
> >
> > changes since v26
> > 1.  add avocado acceptence test
> > 2.  add boot serial test
> >
> > changes since v27
> > 1.  list atmel2560 devices as unimplemented
> > 2.  fix sram base/size
> >
> > changes since v28
> > 1.  rebase
> > 2.  fix includes & build
> >
> > changes since v29
> > 1.  fixing ownership
> > 2.  using 'since' instread of 'added in'
> >
> > changes since v30
> > 1.  rebase
> >
> > changes since v31
> > 1.  splitting 'Add instruction translation' commit
> > 2.  fixing typo in qapi/machine.json sicne -> since
> > 3.  removing unintended changes in configure file
> > 4.  adding Richard Henderson as a co developer to 'Add instruction
> translation - CPU main translation funcions' commit
> >
> > changes since v32
> > 1.  modify cpu_get_sreg to treat sreg C as other flags, except sreg Z
> >
> > changes since v33
> > 1.  ensure flag C is always calculated as one bit
> > 2.  calculate flag Z as one bit, without using inverse logic
> >
> > changes since v34
> > 1.  rebase
> >
> > changes since v35
> > 1.  rebase
> > 2.  use NANOSECONDS_PER_SECOND instead of 1000000000 in avr_timer16.c
> > 3.  split "target/avr: Register AVR support with the rest of QEMU" into
> three patches
> >     1.  "target/avr: Register AVR support with the rest of QEMU"
> >     2.  "target/avr: Update build system"
> >     3.  "target/avr: Update MAINTAINERS file"
> > 4.  split "target/avr: Add tests" patch into two patches
> >     1.  "target/avr: Add Avocado test"
> >     2.  "target/avr: Add boot serial test"
> > 5.  Add instruction disassembly function
> > 6.  change "since 4.2" to "since 5.0"
> >
> > changes since v36
> > 1.  rebase
> > 2.  tename
> >     1.  NO_CPU_REGISTERS    -> NUMBER_OF_CPU_REGISTERS
> >     2.  NO_IO_REGISTERS     -> NUMBER_OF_IO_REGISTERS
> >     3.  to_A                -> to_regs_16_31_by_one
> >     4.  to_B                -> to_regs_16_23_by_one
> >     5.  to_C                -> to_regs_24_30_by_two
> >     6.  to_D                -> to_regs_00_30_by_two
> > 3.  add missing licences
> > 4.  add usage example (see above)
> > 5.  ass Sarah Harris <S.E.Harris@kent.ac.uk> as a reviewer to
> MAINTAINERS
> > 7.  use git commit sha1 instead of `master`` in avocado test
> >
> > Michael Rolnik (16):
> >   target/avr: Add outward facing interfaces and core CPU logic
> >   target/avr: Add instruction helpers
> >   target/avr: Add instruction decoding
> >   target/avr: Add instruction translation - Registers definition
> >   target/avr: Add instruction translation - Arithmetic and Logic
> >     Instructions
> >   target/avr: Add instruction translation - Branch Instructions
> >   target/avr: Add instruction translation - Bit and Bit-test
> >     Instructions
> >   target/avr: Add instruction translation - MCU Control Instructions
> >   target/avr: Add instruction translation - CPU main translation
> >     function
> >   target/avr: Add instruction disassembly function
> >   target/avr: Add example board configuration
> >   target/avr: Register AVR support with the rest of QEMU
> >   target/avr: Update build system
> >   target/avr: Add boot serial test
> >   target/avr: Add Avocado test
> >   target/avr: Update MAINTAINERS file
> >
> > Sarah Harris (1):
> >   target/avr: Add limited support for USART and 16 bit timer peripherals
> >
> >  configure                        |    7 +
> >  default-configs/avr-softmmu.mak  |    5 +
> >  qapi/machine.json                |    3 +-
> >  include/disas/dis-asm.h          |    6 +
> >  include/hw/char/avr_usart.h      |   97 +
> >  include/hw/misc/avr_mask.h       |   47 +
> >  include/hw/timer/avr_timer16.h   |   97 +
> >  include/sysemu/arch_init.h       |    1 +
> >  target/avr/cpu-param.h           |   37 +
> >  target/avr/cpu-qom.h             |   54 +
> >  target/avr/cpu.h                 |  254 +++
> >  target/avr/helper.h              |   29 +
> >  arch_init.c                      |    2 +
> >  hw/avr/sample.c                  |  282 +++
> >  hw/char/avr_usart.c              |  324 ++++
> >  hw/misc/avr_mask.c               |  112 ++
> >  hw/timer/avr_timer16.c           |  605 ++++++
> >  target/avr/cpu.c                 |  576 ++++++
> >  target/avr/disas.c               |  228 +++
> >  target/avr/gdbstub.c             |   85 +
> >  target/avr/helper.c              |  354 ++++
> >  target/avr/machine.c             |  121 ++
> >  target/avr/translate.c           | 3052 ++++++++++++++++++++++++++++++
> >  tests/boot-serial-test.c         |   10 +
> >  tests/machine-none-test.c        |    1 +
> >  MAINTAINERS                      |   11 +
> >  gdb-xml/avr-cpu.xml              |   49 +
> >  hw/Kconfig                       |    1 +
> >  hw/avr/Kconfig                   |    6 +
> >  hw/avr/Makefile.objs             |    1 +
> >  hw/char/Kconfig                  |    3 +
> >  hw/char/Makefile.objs            |    1 +
> >  hw/misc/Kconfig                  |    3 +
> >  hw/misc/Makefile.objs            |    2 +
> >  hw/timer/Kconfig                 |    3 +
> >  hw/timer/Makefile.objs           |    2 +
> >  target/avr/Makefile.objs         |   34 +
> >  target/avr/insn.decode           |  194 ++
> >  tests/Makefile.include           |    2 +
> >  tests/acceptance/machine_avr6.py |   56 +
> >  40 files changed, 6756 insertions(+), 1 deletion(-)
> >  create mode 100644 default-configs/avr-softmmu.mak
> >  create mode 100644 include/hw/char/avr_usart.h
> >  create mode 100644 include/hw/misc/avr_mask.h
> >  create mode 100644 include/hw/timer/avr_timer16.h
> >  create mode 100644 target/avr/cpu-param.h
> >  create mode 100644 target/avr/cpu-qom.h
> >  create mode 100644 target/avr/cpu.h
> >  create mode 100644 target/avr/helper.h
> >  create mode 100644 hw/avr/sample.c
> >  create mode 100644 hw/char/avr_usart.c
> >  create mode 100644 hw/misc/avr_mask.c
> >  create mode 100644 hw/timer/avr_timer16.c
> >  create mode 100644 target/avr/cpu.c
> >  create mode 100644 target/avr/disas.c
> >  create mode 100644 target/avr/gdbstub.c
> >  create mode 100644 target/avr/helper.c
> >  create mode 100644 target/avr/machine.c
> >  create mode 100644 target/avr/translate.c
> >  create mode 100644 gdb-xml/avr-cpu.xml
> >  create mode 100644 hw/avr/Kconfig
> >  create mode 100644 hw/avr/Makefile.objs
> >  create mode 100644 target/avr/Makefile.objs
> >  create mode 100644 target/avr/insn.decode
> >  create mode 100644 tests/acceptance/machine_avr6.py
> >
> > --
> > 2.17.2 (Apple Git-113)
> >
>


-- 
Best Regards,
Michael Rolnik

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