Tag: hacking

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cache hacks

admin

https://dmalcolm.fedorapeople.org/gcc/2015-08-31/rst-experiment/how-to-use-inline-assembly-language-in-c-code.html#clobbers

compiler explorer:
https://godbolt.org/z/kANkNL

void maccess(void *p) { asm volatile("movq (%0), %%rax\n" : : "c"(p) : "rax"); }

moves quadword from mem adress into rax register
AT&T syntax?

shm_open and mmap:

quote: mmap works in multiples of the page size on your system. If you're doing this on i386/amd64 or actually most modern CPUs, this will be 4096.

In the man page of mmap on my system it says: "offset must be a multiple of the page size as returned by sysconf(_SC_PAGE_SIZE).". On some systems for historical reasons the length argument may be not a multiple of page size, but mmap will round up to a full page in that case anyway.

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