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Richard Russell
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xx Calling ARM programmers
« Thread started on: Jul 7th, 2017, 1:45pm »

Those of you who have tried the Raspberry Pi edition of BBCSDL will have spotted that neither the Run... Debug nor Run... Profile options are available. This is because both rely on 'sdldebug.bbc' (in the @lib$ folder) which contains a substantial amount of assembler code, which of course is x86-specific.

It would obviously be highly desirable for those debugging options to work on the RPi, but to do so it will require an ARM version of 'sdldebug.bbc' to be written. Since I'm not an ARM programmer (far from it!) this is not something I can contribute to.

There must be people here with a background in programming the Acorn Archimedes or RISC PC, who have some experience with ARM assembly language. I would greatly appreciate it if somebody would volunteer to write and test the required code.

Richard.
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Richard Russell
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xx Re: Calling ARM programmers
« Reply #1 on: Jul 14th, 2017, 2:53pm »

on Jul 7th, 2017, 1:45pm, Richard Russell wrote:
I would greatly appreciate it if somebody would volunteer to write and test the required code.

Do I have to beg, or offer a cash reward, to get a response? If it's the latter, I'm open to negotiation!

Richard.
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hellomike
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xx Re: Calling ARM programmers
« Reply #2 on: Jul 15th, 2017, 3:49pm »

You seem to have tackled the ARM code in 'sortlib.bbc' or, if you had help, can you not approach that source again?
« Last Edit: Jul 15th, 2017, 3:49pm by hellomike » User IP Logged

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xx Re: Calling ARM programmers
« Reply #3 on: Jul 15th, 2017, 8:26pm »

on Jul 15th, 2017, 3:49pm, hellomike wrote:
You seem to have tackled the ARM code in 'sortlib.bbc' or, if you had help, can you not approach that source again?

SORTLIB was created in an entirely different way: I wrote the algorithm in C and then compiled it using GCC to an ARM 'binary blob'. I neither "tackled" the ARM code myself nor did I receive help from anybody else. This technique was only made possible because of the self-contained nature of the sorting code.

If you look at the code of 'sdldebug.bbc' you will realise that it's quite unsuitable for that approach. For example the assembler code makes calls to external (SDL) API functions, which if compiled would require some kind of run-time linking to resolve those addresses. Also the code accesses BBC BASIC's variables, again at addresses that are unknown at 'compile time'.

You will be aware that one of the strengths of BBC BASIC is that since the assembly process happens at run-time it can make use of values that are only known then, whereas a compiler can only make such references via dynamic linking (or by passing all the addresses as parameters).

I am sorry that you felt obliged to make such a negative comment.

Richard.
« Last Edit: Jul 15th, 2017, 8:43pm by Richard Russell » User IP Logged

hellomike
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xx Re: Calling ARM programmers
« Reply #4 on: Jul 16th, 2017, 07:45am »

I was just wondering.

After all the praise I expressed about BB4W to all and everyone for years and years, I feel offended that apparently, you find me capable of commenting anything negative huh
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