TinyC, port to HP

From: David Betz <dbetz_at_xlisper.mv.com>
Date: Fri Oct 10 17:17:28 2003

Hendrix always seems to get the credit for Small C but the original
compiler was written by Ron Cain and published in an early issue of Dr.
Dobbs Journal. The earlier version by Ron Cain was quite a bit smaller
than Hendrix version.

On Friday, October 10, 2003, at 04:54 PM, jim wrote:

>
>
>
>>
>>> J.C. Wren wrote:
>>>> A number of C compilers on small architectures have solved this
>>>> problem
>> by
>>>> having 2, sometimes 4, distinct compiling phases, and passing data
>> through
>>>> temporary files. This gives you a lot more leeway in code space.
>>>> I've
>> seen
>>>> preprocessor pass, tokenization pass, code generator pass, and in
>>>> some
>> cases,
>>>> the 4th pass is the assembler (which I generally prefer over
>>>> direct-to-assembly, since you can insert a user-written processing
>>>> phase
>>
>
> I ported Hendrix tiny C from my Imsai (CP/M version 1.4 actually) to a
> mini
> computer that had no c support in the early 80's when it first came
> out.
>
> If I recall it came in two passes as mentioned, and then an assembly,
> then
> link.
>
> There was a c library support as well.
>
> I actually didn't to go assembly for the mini, but actually to an
> interpreted
> language like Java uses now. I think I had to implement around 30
> opcodes
> total to implement the instructions used by the hendrix compiler.
> that means
> that of all the 8080 instructions that the original hendrix compiler
> emitted,
> there
> were only 30 total used.
>
> It supports a 16 bit address space natively, so would produce good
> code on
> your HP.
>
> A typical pass was as follows:
>
> run C0 on the c source
> run C1 on the result of C0
> merge the source for the clib (which was earlier run thru C0 and C1)
> with
> this output of C1.
>
> Assemble the whole mess with an assembler that assembled to a
> relocatable module.
>
> take relocatable module, and use load command to suck into interpreter
> on target machine (which was written in assembly).
>
> I don't know about running in 32k. That probably would be tight to
> run the compiler. I think the full C lib was around 24k long, but it
> may
> have been smaller. Since i linked in the whole mess w/o any way to
> pick and choose what was used vs what was not, it was allways
> there regardless. A better linker and better way of merging in the
> clib could fix that.
>
> the machine I had had a symbolic assembler that was easy to gen up
> the assembler used here w/o any work so I didn't optimize that at
> all.
>
> As to optimization, you do have to do some duplicate elimination,
> but other than that, it produced pretty good code.
>
> most of the work on the hendrix c compiler was to the C1 pass,
> which emitted the 8080 instructions. I don't recall whether the
> Hendrix Tiny C was orignally for the 8080 / CP/M environment,
> or whether the published version was a port from some other
> environment, but the one I worked from ran on either CP/M 1.4
> or 2 or 3x cpm's. the clib was pretty brain dead.
>
> Jim
>
Received on Fri Oct 10 2003 - 17:17:28 BST