Files
linux-kernel-module-cheat/userland/arch/x86_64/inline_asm/scratch_hardcode.c
Ciro Santilli 六四事件 法轮功 a90271c6af asm: start x86 intrinsics examples
Split userland/arch/<arch>/c/ into inline_asm and intrinsics, and move programs
that don't match either up.
2019-05-31 00:00:00 +00:00

23 lines
598 B
C

/* This is a worse version of scratch.c with hardcoded scratch.
* https://github.com/cirosantilli/linux-kernel-module-cheat#gcc-inline-assembly-scratch-registers
*/
#include <assert.h>
#include <inttypes.h>
int main(void) {
uint64_t in1 = 0xFFFFFFFF;
uint64_t in2 = 1;
uint64_t out;
__asm__ (
"mov %[in2], %%rax;" /* scratch = in2 */
"add %[in1], %%rax;" /* scratch += in1 */
"mov %%rax, %[out];" /* out = scratch */
: [out] "=r" (out)
: [in1] "r" (in1),
[in2] "r" (in2)
: "rax"
);
assert(out == 0x100000000);
}