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in irq.c..this is how my functions are declared
extern void irq0();
extern void irq1();
....
and their definitions are in my assembly file start.asm
global _irq0
global _irq1
..
_irq0:
cli
push byte 0
push byte 32
jmp irq_common_stub

_irq1:
cli
push byte 0
push byte 33
jmp irq_common_stub

and here is my linker script link.ld
ENTRY(_kmain)
phys = 0x00100000;
SECTIONS
{
.text phys : AT(phys) {
code = .;
*(.text)
*(.rodata)
. = ALIGN(4096);
}
.data : AT(phys + (data - code))
{
data = .;
*(.data)
. = ALIGN(4096);
}
.bss : AT(phys + (bss - code))
{
bss = .;
*(.bss)
. = ALIGN(4096);
}
end = .;
}

where _kmain refers to my kernel's entry c main file

im using the mingw compliler and nasm assembler nad following are the commands im using to compiler the kernel
nasm -f win32 -o start.o start.asm

gcc -Wall -O -fstrength-reduce -fomit-frame-pointer -finline-functions -nostdinc -fno-builtin -I./include -c -o main.o main.c
gcc -Wall -O -fstrength-reduce -fomit-frame-pointer -finline-functions -nostdinc -fno-builtin -I./include -c -o irq.o irq.c

ld -oformat -Tlink.ld start.o main.o irq.o
and im getting the following errors
irq.o : irq.c:(.text+0x10c): undefined reference to `irq0'
irq.o : irq.c:(.text+0x130): undefined reference to `irq1'

so what would could be the problem guys ??
p.s in linker script when i change the _kmain to start i get an error corresponding to undefined reference to _main

Function names are different in the declaration from the definition. Didn't you see it ?

gcc default not to generate underscore, as contrast with VC.

i've tried by removing the _ from the definition bt still its not working

also im able to call the function defined in C eg kmain bt not able to access the function defined in assembly which is declared as extern in c..

The typical other cause is that you didn't put your assembly code in a section.

What concerns me more however, is that your current approach is actually including windows libraries.

so how can i put the assembly code in the section

please if u could put some light on how my approach is including the windows lib...
im new in this so if u cud help me out here

And "u" could try to show us a bit of effort (like writing "you" instead of "u" et cetera).

will you show what symobols that are inside the objects.

You should understand that nasm will create symbols with names _irq0 and _irq1 in the objectfile. If you dont tell gcc/gas to do the same it will look for the "extern" symbols without _ and there will be no match. Another option is to skip the _ in the nasm file. Depending on your preference.

dansmahajan wrote:please if u could put some light on how my approach is including the windows lib...

It's caused by you not doing your homework. See the forum rules for hints

i have tried the same procedure on the cross compiler but still i am getting the same error "Undefined reference to irq"
i have also tried the -fleading-underscore , -fnoleading-underscore but still problem is persisting...
so what should i do now ??

Hi dansmahajan

I suggest you that use objdum -t or nm programs to see the symbols table of your programs and delete those options such as -fleading-underscore , -fnoleading-underscore.