clock_nanosleep

high-resolution sleep with specifiable clock

sys_clock_nanosleep(clockid_t which_clock, int flags, const struct __kernel_timespec *rqtp, struct __kernel_timespec *rmtp)

register	value
`a7`	115, the syscall number
`a0`	clockid_t which_clock
`a1`	int flags
`a2`	const struct __kernel_timespec *rqtp
`a3`	struct __kernel_timespec *rmtp
`a0`	the return value

Then run ecall to enter the kernel.

Same syscall on other architectures