Last active
May 15, 2024 20:12
-
-
Save pankkor/edfbde50dcce45152f6458f6f1f1595b to your computer and use it in GitHub Desktop.
Example of using gcc inline assembly syntax. NOTE: last time I checked clang, didn't support Intel assembly syntax, so AT&T it is.
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
static void test_asm(u8 *data, u64 bytes) { | |
#if defined(__aarch64__) | |
__asm__ volatile ( | |
"cbz %[bytes], 1f\n\t" | |
"mov x9, #0\n\t" | |
"0: strb w9, [%[data], x9]\n\t" | |
"add x9, x9, #1\n\t" | |
"cmp %[bytes], x9\n\t" | |
"b.ne 0b\n\t" | |
"1:\n\t" | |
: /* no output */ | |
: [data] "r" (data), [bytes] "r" (bytes) | |
: "memory", "x9"); | |
#elif defined(__x86_64__) | |
__asm__ volatile ( | |
"testq %[bytes], %[bytes]\n\t" | |
"je 1f\n\t" | |
"xorl %%eax, %%eax\n\t" | |
"0: movb %%al, (%[data],%%rax)\n\t" | |
"incq %%rax\n\t" | |
"cmpq %%rax, %[bytes]\n\t" | |
"jne 0b\n\t" | |
"1:\n\t" | |
: /* no output */ | |
: [data] "r" (data), [bytes] "r" (bytes) | |
: "memory", "rax"); | |
#else | |
#error Not implemented | |
#endif // #if defined(__aarch64__) | |
} |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment