Hi Tristan,
The change that made things work, in the risc-v\dict_prims.inc file:
line 43
# lw x10, 0(x17) # @W, address of some executable code
lh x10, 0(x17) # @W, address of some executable code
This works because on a CH32x033 the dictionary resides in flash below the
64K boundary
addressable by a halfword (16 bits), and only has 62K of flash. By doing
this you can also keep the dictionary more compact in flash.
For larger flash devices where the dictionary resides is going to be a
factor to consider, some RISCV processors may not have an issue in crossing
32 bit word boundaries but the one for CH32x033 does. The RISCV processors
that don't have this issue (CH32V307?) can use the lw (load word) version
of the instruction. The CH32V003 -> CH32V007 and CH32V203 should use the lh
(load halfword) version.
Hope this helps others who want to use amforth on smaller RISCV chips
John S
On Wed, Jan 7, 2026 at 9:35 AM John Sarabacha <[email protected]> wrote:
> Hi Tristan,
> I had sent a couple of pictures (of this environment) that apparently is
> being held by the sourceforge administrator for review because of the size
> of the email.
> The mcu uses it's own internal clock (fixed at 48Mhz) without any issues,
> breakout boards are also being used, the chips are soldered to the break
> out boards using solder paste and a T-962 oven (available from amazon). The
> breakout boards with the chip (mcu) become nodes on a network (similar to a
> RS485 type of network). It now becomes possible to go even smaller
> (CH32V003 ... CH32V007) but the cost these chips vs CH32X033 doesn't give
> you a better advantage (e.g size of sram and features). Where amForth is
> useful here is programming these chips remotely and changing these programs
> as needed. AmForth was the missing piece of the puzzle, the CH32X033 is a
> node on a network already functional and communicating with PIC16F1824
> nodes and running for years without significant problems but not easily
> re-programmable remotely. Things have changed significantly, compare the
> cost of a CH32X033 (32 bit) chip vs PIC16F1824 (8 bit) not to mention sram
> and flash size differences.
>
> Regards,
> John S
>
> Regards,
> John S.
>
>
>
>
> On Wed, Jan 7, 2026 at 2:30 AM <[email protected]> wrote:
>
>> Hi John,
>>
>> A very interesting and ambitious use of AmForth! Sounds like you
>> overcame your compiler/linker alignment issue.
>>
>> > The CH32X033 chip also hosts an additional eight bit RISC processor
>> > (pioc)
>>
>> I didn't know about this. Interesting.
>>
>> > The test environment is very simple, a CH32V033 chip in a
>> > 20 pin chip adapter connected to a WCH-LinkE and using
>> > MounStudio v2.3.0 for programming and debugging.
>>
>> How are you clocking the mcu?
>>
>> Best wishes,
>> Tristan
>>
>>
>> On 2026-01-07 05:41, John Sarabacha wrote:
>> > The CH32V033 is now able to execute the amForth XT words without any
>> > problems, MounStudio with debugging allowed me to set program break
>> > points
>> > to see the execution of each XT code segment along with the registers
>> > (tos,
>> > ip, sp dp) so it looks very promising. The vendor's startup code and C
>> > libraries are used to initialize system clocks, peripherals (usart,
>> > GPIO...) this saves a tremendous amount of work.
>> > The existing flash image contains the dictionary that the hifive
>> > application used which is an overkill for what my application needs, so
>> > the
>> > next step is to remove unnecessary dictionary entries e.g
>> > initialization
>> > (commenting out the unnecessary include files) and rebuild the image.
>> > The amForth codebase in CH32V033 will use the C library drivers for IO
>> > (usart, gpio, pioc, networking ... ). The CH32X033 chip also hosts an
>> > additional eight bit RISC processor (pioc) which amForth can work with
>> > for
>> > high speed custom IO. To test the amForth code and dictionary a test
>> > sequence of XT tokens will be passed to the amForth VM (execution loop)
>> > and
>> > monitor the results (tos ... ). The test environment is very simple, a
>> > CH32V033 chip in a 20 pin chip adapter connected to a WCH-LinkE and
>> > using
>> > MounStudio v2.3.0 for programming and debugging.
>> >
>> > Hope this information is useful to others,
>> > John S
>> >
>> >
>> > On Tue, Jan 6, 2026 at 4:37 PM John Sarabacha <[email protected]>
>> > wrote:
>> >
>> >> Hi Tristan,
>> >> Some good news, CH32V033 is now able to run amForth co-existing with
>> >> C
>> >> and other inline routines. A change was made to the the execution loop
>> >> which doesn't impact performance and the keeps image size to a
>> >> minimum.
>> >> Next step is to test amForth using C code to pass ascii strings to the
>> >> interpreter to see if it works.
>> >>
>> >> Regards,
>> >> John S
>> >>
>> >>
>> >>
>> >> On Tue, Jan 6, 2026 at 3:14 PM John Sarabacha <[email protected]>
>> >> wrote:
>> >>
>> >>> Hi Tristan,
>> >>> This has and is being looked at. The linker appears to be the
>> >>> problem. I
>> >>> have tried a few
>> >>> things like changes to the macros with some success. With these
>> >>> successes
>> >>> the image sizes grow.
>> >>> The run time execution loop is able to function until it hits a
>> >>> halfword
>> >>> address then it exceptions out.
>> >>> As a temporary workaround I am looking at handling the exception
>> >>> gracefully and resuming the execution
>> >>> loop, this way the image size can be kept smaller. The good news is
>> >>> that
>> >>> it (amForth) is able to co-exist with
>> >>> my existing application which is a mix of C and inline assembler
>> >>> routines.
>> >>>
>> >>> Regards,
>> >>> John S
>> >>>
>> >>> On Tue, Jan 6, 2026 at 1:53 PM <[email protected]> wrote:
>> >>>
>> >>>> Hi John,
>> >>>>
>> >>>> Check your compiler/assembler/linker options to see whether they
>> >>>> allow
>> >>>> free reign to use RISC-V compressed instructions wherever they think
>> >>>> appropriate. Then, as a first cut, turn that off globally. There are
>> >>>> various ways to be more selective, but it very much depends on how
>> >>>> much
>> >>>> their use matters to you.
>> >>>>
>> >>>> Best wishes,
>> >>>> Tristan
>> >>>>
>> >>>> On 2026-01-06 16:33, John Sarabacha wrote:
>> >>>> > Hi everyone,
>> >>>> > When mixing C *.c and assembler *.s files in your amForth build you
>> >>>> can
>> >>>> > run
>> >>>> > into random 32 bit alignment issues with the dictionary. The
>> >>>> Cortex-M4
>> >>>> > and
>> >>>> > RISCV on CH32V307 appears to be more forgiving than
>> CH32X033/CH32X035
>> >>>> > is.
>> >>>> > Using the -m32 switch for GCC/assembler chain doesn't help. The
>> >>>> > strange
>> >>>> > part is that the 32 bit mis-alignment doesn't always occur. It
>> only
>> >>>> > happens for certain dictionary elements like
>> >>>> > 000015be <XT_DOLITERAL>:
>> >>>> > 15be: 15c2
>> >>>> > 000015c2 <PFA_DOLITERAL>:
>> >>>> >
>> >>>> > Regards,
>> >>>> > John S
>> >>>> >
>> >>>> > _______________________________________________
>> >>>> > Amforth-devel mailing list for http://amforth.sf.net/
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>> >>>>
>> >>>>
>> >>>> _______________________________________________
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>> >>>>
>> >>>
>> >
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