[Qemu-devel] Some line of codes in a file that I cant understand

[Qemu-devel] Some line of codes in a file that I cant understand

[Atlas Khan]

[-- Attachment #1: Type: text/plain, Size: 1083 bytes --]

I am watching i8259.c in \hw folder in QEMU. here is something like this


static const VMStateDescription vmstate_pic = {
    .name = "i8259",
    .version_id = 1,
    .minimum_version_id = 1,
    .minimum_version_id_old = 1,
    .fields = (VMStateField[]) {
        VMSTATE_UINT8(last_irr, PicState),
        VMSTATE_UINT8(irr, PicState),
        VMSTATE_UINT8(imr, PicState),
        VMSTATE_UINT8(isr, PicState),
        VMSTATE_UINT8(priority_add, PicState),
        VMSTATE_UINT8(irq_base, PicSthisate),
        VMSTATE_UINT8(read_reg_select, PicState),
        VMSTATE_UINT8(poll, PicState),
        VMSTATE_UINT8(special_mask, PicState),
        VMSTATE_UINT8(init_state, PicState),
        VMSTATE_UINT8(auto_eoi, PicState),
        VMSTATE_UINT8(rotate_on_auto_eoi, PicState),
        VMSTATE_UINT8(special_fully_nested_mode, PicState),
        VMSTATE_UINT8(init4, PicState),
        VMSTATE_UINT8(single_mode, PicState),
        VMSTATE_UINT8(elcr, PicState),
        VMSTATE_END_OF_LIST()
    }
};

here what does this dot shows and what is this VMSTATE_UINT8 function?

[-- Attachment #2: Type: text/html, Size: 1438 bytes --]

Re: [Qemu-devel] Some line of codes in a file that I cant understand

[Dr. David Alan Gilbert]

* Atlas Khan (atlaskhan90@gmail.com) wrote:
> I am watching i8259.c in \hw folder in QEMU. here is something like this
> 
> 
> static const VMStateDescription vmstate_pic = {
>     .name = "i8259",
>     .version_id = 1,
>     .minimum_version_id = 1,
>     .minimum_version_id_old = 1,
>     .fields = (VMStateField[]) {
>         VMSTATE_UINT8(last_irr, PicState),
>         VMSTATE_UINT8(irr, PicState),
>         VMSTATE_UINT8(imr, PicState),
>         VMSTATE_UINT8(isr, PicState),
>         VMSTATE_UINT8(priority_add, PicState),
>         VMSTATE_UINT8(irq_base, PicSthisate),
>         VMSTATE_UINT8(read_reg_select, PicState),
>         VMSTATE_UINT8(poll, PicState),
>         VMSTATE_UINT8(special_mask, PicState),
>         VMSTATE_UINT8(init_state, PicState),
>         VMSTATE_UINT8(auto_eoi, PicState),
>         VMSTATE_UINT8(rotate_on_auto_eoi, PicState),
>         VMSTATE_UINT8(special_fully_nested_mode, PicState),
>         VMSTATE_UINT8(init4, PicState),
>         VMSTATE_UINT8(single_mode, PicState),
>         VMSTATE_UINT8(elcr, PicState),
>         VMSTATE_END_OF_LIST()
>     }
> };
> 
> here what does this dot shows and what is this VMSTATE_UINT8 function?

The . is about assigning into named fields in a structure; it's just
neater than the old C way of having to keep all the fields in order.
See the def of VMStateDescription in include/migration/vmstate.h

The VMSTATE_UINT8 is a macro declaring that there is a byte/uint8 member
see ./include/migration/vmstate.h and docs/migration.txt for a bit
of a description.

Dave
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK