User:Columbus/OR1K BareBones

Here a conversion of the Bare Bones tutorial to or1k.

Sources

boot.asm

# Declare constants for multiboot header.
.set ALIGN,    1<<0
.set MEMINFO,  1<<1
.set FLAGS,    ALIGN | MEMINFO
.set MAGIC,    0x1BADB002
.set CHECKSUM, -(MAGIC + FLAGS)

.section .multiboot
.align 4
.long MAGIC
.long FLAGS
.long CHECKSUM

.section .bootstrap_stack, "aw", @nobits
stack_bottom:
.skip 16384 # 16 KiB
stack_top:

.section .text
.global _start
.type _start, @function
_start:
    # I think/hope, this sets the stack pointer
    l.movhi r3, hi(stack_top)
    l.ori   r3, r3, lo(stack_top)
    l.sw    0(r3), r1

    # I hope this calls kernel_main
    l.jal kernel_main

.Lhang:
    l.nop
    l.j .Lhang

.size _start, . - _start

main.c

Can be the same, as in Bare Bones.

linker.ld

Can be the same, as in Bare Bones.

Compilation

or1k-elf-as boot.asm -o boot.o
or1k-elf-g++ -c main.c -o main.o -ffreestanding -O2 -Wall -Wextra -fno-exceptions -fno-rtti
or1k-elf-gcc -T linker.ld -o kernel -ffreestanding -O2 -nostdlib boot.o main.o -lgcc

Execution

Honestly, I don't know, if anything was right about the compilation, or boot.asm, and I also have no idea how to execute it. On my machine everything worked fine, until the execution.