From mboxrd@z Thu Jan 1 00:00:00 1970 From: roman@mailoo.org (roman at mailoo.org) Date: Fri, 30 Sep 2016 19:09:13 +0200 Subject: Virtual Address Space In-Reply-To: <14E2A3CD-F29A-466B-A162-EACA67AC4C50@gmail.com> References: <14E2A3CD-F29A-466B-A162-EACA67AC4C50@gmail.com> Message-ID: <93c5e2c146e226d7f6a5e9bd613c9f0b@mailoo.org> To: kernelnewbies@lists.kernelnewbies.org List-Id: kernelnewbies.lists.kernelnewbies.org 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 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 > > _______________________________________________ > Kernelnewbies mailing list > Kernelnewbies at kernelnewbies.org > https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.kernelnewbies.org/pipermail/kernelnewbies/attachments/20160930/485177b8/attachment.html