From: roman@mailoo.org (roman at mailoo.org)
To: kernelnewbies@lists.kernelnewbies.org
Subject: Virtual Address Space
Date: Fri, 30 Sep 2016 19:09:13 +0200 [thread overview]
Message-ID: <93c5e2c146e226d7f6a5e9bd613c9f0b@mailoo.org> (raw)
In-Reply-To: <14E2A3CD-F29A-466B-A162-EACA67AC4C50@gmail.com>
Hi,
I COMPILE MAIN.S and it generates MAIN.O. With objdump I can see:
0000000000000000 <_start>:
0: b8 01 00 00 00 mov $0x1,%eax
5: bb 00 00 00 00 mov $0x0,%ebx
a: cd 80 int $0x80
After LINK MAIN.O it generates MAIN. With objdump I now can see:
0000000000400078 <_start>:
400078: b8 01 00 00 00 mov $0x1,%eax
40007d: bb 00 00 00 00 mov $0x0,%ebx
400082: cd 80 int $0x80
So, linker generates virtual address, doesn't it? But why it starts at
400078 and not in other any location? Is there any logic here? A virtual
address can start at 0?
Regards.
El 29.09.2016 09:25, arshad hussain escribi?:
>> On 28-Sep-2016, at 10:36 am, Madhu K <madhu.sk89@gmail.com> wrote:
>>
>> Hi All,
>
> The support comes right through from the architecture.
>
> Linear address: Also virtual address. This is Address CPU can address. This is 0 - 4GB under 32bit architecture.
> Physical address: This are actual memory installed in your system. Linear address have to be converted to
> physical address eventually. MMU translate linear address with the help of paging to physical address.
>
>> This is to understand the Virtual address space.Basically who generates the virtual addresses CPU or GNU compiler?
>
> A program image generated by compiler & linker uses Virtual Address . During execution of the program CPU + MMU
> translates or maps each virtual address to physical address.
>
> Net-net this is architecture dependent and would highly recommend reading Intel's Architecture Manual for your reference.
>
>> Thanks
>> Madhu
>> _______________________________________________
>> Kernelnewbies mailing list
>> Kernelnewbies at kernelnewbies.org
>> https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
> _______________________________________________
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next prev parent reply other threads:[~2016-09-30 17:09 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-28 5:06 Virtual Address Space Madhu K
2016-09-28 6:05 ` Arun Sudhilal
2016-09-28 10:11 ` Madhu K
2016-09-28 10:59 ` Prabhunath G
2016-09-28 13:32 ` Gadre Nayan
2016-09-30 16:40 ` Román Martínez
2016-10-02 2:52 ` Arshad Hussain
2016-10-03 5:12 ` Madhu K
2016-09-28 6:09 ` Greg KH
2016-09-28 10:14 ` Madhu K
2016-09-28 10:29 ` Greg KH
2016-09-28 9:14 ` Augusto Mecking Caringi
2016-09-28 10:21 ` Madhu K
2016-09-28 10:37 ` Alexander Kapshuk
2016-09-29 7:25 ` arshad hussain
2016-09-30 17:09 ` roman at mailoo.org [this message]
2016-10-01 18:02 ` piyush moghe
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