On 20 October 2012 09:23, Timo Sintonen <t.sinto...@luukku.com> wrote: >> >> Nobody has used GDC/D/druntime on a system without OS afaik. So you >> have to pioneer ;-) > > > So I have to try it on my own... > > >> * Create your own, simple runtime library. There's no real >> documentation on the minimum interface a runtime must implement (the >> compiler calls back into the runtime), so this would be a little >> tricky. > > > I have already made some tests: > > I compiled a simple class without any library. The missing symbols tell me > what is the minimum that is expected to be in Object class. > > I tried to compile an empty Object class. There is some problems because > Object seems to be a reserved word in gdc. The biggest problem is that gdc > gets an internal error every time I try to compile my own Object. If this is > an unknown bug in gdc, I may look it again. (an internal compiler error is > always a bug, isn't it?) > > >> * Adjust druntime. You can probably throw out 90% of the druntime code > > > I compiled object.d without imports and commented out everything that failed > the compilation. There is still some missing symbols but I think this > version would not work anyway. > > I have a working glibc, newlib and my own minimum libc. So I would follow > the linux version as far as possible. Because Linux is a reserved word I > changed with sed all the linux version checks to another word and got nearly > all compiled. First time I got over 400 lines of missisng symbols but I > could see what functions are expected from the c library. > >> >> >> Your biggest >> problem is probably the GC and TLS. > > > To be more general, the library should have a minimum version with no > threads and gc and be configurable to have them. In controller world > resources are limited. We talk about kilobytes when pc people talk about > gigabytes. The advantage is that everything is usually fixed and known at > design time. Memory is usually allocated once and kept as long as the device > is operating. The same is for threads. Threads are initiated at startup and > have only one instance. They keep running as long as the device is > operating. In the threading system I use now the main loop of each thread is > run once and at the end of the loop control is returned to the scheduler > which jumps to the next thread. > > So the application can run without gc and tls. On the other hand, the amount > of threads is known. It is even possible to hardcode tls address for every > thread if needed. Memory pool and stack are also in fixed addresses and all > pointers are available. So the low level stuff would be quite simple. The > biggest job is to get it work with the higher level code. > >
Quick question, what is defined in your phobos-vers-syms file? (This will be located in the libphobos / libdruntime build directory). Regards -- Iain Buclaw *(p < e ? p++ : p) = (c & 0x0f) + '0';
