Linking error - undefined references

[abcdef4bfd]

I'm tried to implement IDT & ISRs for my OS. I known that it requires a lot of assembly code, added it to other .asm file, compiled and linked it. But ld is gived me errors.
kernel.cpp:(.text+0x4971): undefined reference to 'isr0()'
Lots of this errors is appeared. I think that the problem is in my link command:

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i686-elf-ld -T link.ld -o os365.bin -O2 -nostdlib idt.o boot.o kernel.o

And, more global, any assembly code in separate files is not linking for me.

[Roman]

And, more global, any assembly code in separate files is not linking for me.

Perhaps you miss using the .globl directive?

[abcdef4bfd]

And, more global, any assembly code in separate files is not linking for me.

Perhaps you miss using the .globl directive?

No, i'm written in ASM code that:

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global isr0
; 0 to 31.
global isr31

[Roman]

And how do you build your assembly file?

[abcdef4bfd]

And how do you build your assembly file?

yasm idt.asm -o idt.o -f elf32

[Techel]

Since magic isn't discovered yet you should post your linker script, I bet, so we can help you in the way we can check it and reply.

[abcdef4bfd]

Since magic isn't discovered yet you should post your linker script, I bet, so we can help you in the way we can check it and reply.

It's the same as in the Bare Bones tutorial.

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ENTRY(_start)
SECTIONS
{
	. = 1M;
	.text BLOCK(4K) : ALIGN(4K)
	{
		*(.multiboot)
		*(.text)
	}
	.rodata BLOCK(4K) : ALIGN(4K)
	{
		*(.rodata)
	}
	.data BLOCK(4K) : ALIGN(4K)
	{
		*(.data)
	}
	.bss BLOCK(4K) : ALIGN(4K)
	{
		*(COMMON)
		*(.bss)
		*(.bootstrap_stack)
	}
}

[Roman]

How does the assembly code look like?

[abcdef4bfd]

How does the assembly code look like?

It's from Bran's kernel development tutorial.

[Techel]

So it is exactly the same? Then it are the tools from where the problem came.
And, keep in mind, the c++ compiler is not very kind. It will mangle the symbols in a way its not easy detecting such errors, I can say.

[Combuster]

It's the same as in the Bare Bones

It's from Bran's kernel development tutorial.

Shame on you for mix&matching tutorials, and then complaining here because you can't even sort out the simple things such as an undefined symbol, as it is basically the first error you encounter as a C developer when you make a typo.

The solution is in every case a homework exercise:
- Which source file or library should have that symbol? Does it? Really?
- Which object file should have that symbol? Does it? Really?
- Are you actually adding it in the linking process?

My crystal ball says you failed at both #1 and #3.

[abcdef4bfd]

It's the same as in the Bare Bones

It's from Bran's kernel development tutorial.

Shame on you for mix&matching tutorials, and then complaining here because you can't even sort out the simple things such as an undefined symbol, as it is basically the first error you encounter as a C developer when you make a typo.

The solution is in every case a homework exercise:
- Which source file or library should have that symbol? Does it? Really?
- Which object file should have that symbol? Does it? Really?
- Are you actually adding it in the linking process?

My crystal ball says you failed at both #1 and #3.

1) idt.asm, and really haves it.
2) idt.o.
3) Adding.

[Techel]

Your c++ compiler, when referring to 'idt0()', will import it as a mangled symbol, eg 'xz164_v0idt0' or something like this. Use 'extern "c"' to import it as '_idt0'. Then you also have to change your asm file to export '_idt0'.

[abcdef4bfd]

Your c++ compiler, when referring to 'idt0()', will import it as a mangled symbol, eg 'xz164_v0idt0' or something like this. Use 'extern "c"' to import it as '_idt0'. Then you also have to change your asm file to export '_idt0'.

Tried your method, not working for me. Can you give me your linker script, please?

[Combuster]

Use 'extern "c"' to import it as '_idt0'. Then you also have to change your asm file to export '_idt0'.

Why are you still not using a crosscompiler?