On Wed, Jan 9, 2013 at 2:14 PM, horseriver <horserivers@xxxxxxxxx> wrote:
>
> 1. why use "fc ff ff ff " in call instruction?
Answered by John Fine.
> 2. In my .c source file ,I have not used strcpy function , so why it is disassembly out here ?
> after research , I find this call instruction is corresponding to this line :
>
> sprintf(acpi_device_name(device), "%s", ACPI_EC_DEVICE_NAME);
> sprintf is a externel implemented function .
>
> but why in disassebly code it is strcpy ?
>
> whether something wrong with relocation data?
This is a GCC optimization. GCC converts
sprintf(buf, "%s", arg);
into
strcpy(buf, arg);
because the operations are equivalent and strcpy is more efficient.
By default GCC assumes that it can call any function in the C standard
library. To turn off this assumption, use the -fno-hosted option that
I already mentioned earlier.
Ian
