Conversation

Conversation

Notices

Vertigo (vertigo@mastodon.social)'s status on Saturday, 02-Sep-2017 12:15:06 EDT Vertigo

YES! Major milestone achieved with the Kestrel project. I managed to run my first C program on the Kestrel-2DX. https://hackaday.io/project/10035-kestrel-computer-project/log/66294-kestrel-2dx-runs-its-first-c-program
This does two things for me:
1) Finally have an approach to running C code, so I no longer have a need to port/invent a different programming language.
2) It vindicates the compatibility of my homebrew processor design against the RISC-V ISA specifications.
(I've since improved my build process since I posted the article.)
In conversation Saturday, 02-Sep-2017 12:15:06 EDT from mastodon.social permalink
Attachments
1. Invalid filename.
  
  Kestrel-2DX Runs its First C Program | Details | Hackaday.io
  So, I decided to try getting my RISC-V GCC compiler working with my Kestrel-2DX again, and this time, for whatever reason, my mental model just "clicked" and things worked. It was an iterative process to get this far; however, I'll describe things in the rough order I've accomplished things.
  Here's the C program I wanted to run:
  /* Invert the contents of the video frame buffer on cold boot. */ unsigned long long *scrp, *endp; void _start(void) { scrp = (unsigned long long *)0x10000; endp = scrp + 2000; while(scrp < endp) { *scrp ^= 0xFFFFFFFFFFFFFFFF; scrp++; } while(1) ; }
  I was able to compile this into statically-linked ELF binary file with the following command:
  ./riscv64-unknown-elf-gcc -O1 -c floop.c -o floop.o -march=RV64I ./riscv64-unknown-elf-ld floop.ld floop.o -o floop.exe -nostdlib
  You'll notice that I have a custom loader script, which looks like this:
  ENTRY(_start) MEMORY { ROM (rx) : ORIGIN = 0x00000, LENGTH = 0x8000

Public

Notices