fusl/src/internal/x86_64/syscall.s

.global __syscall
.hidden __syscall
.type __syscall,@function
__syscall:
	movq %rdi,%rax
	movq %rsi,%rdi
	movq %rdx,%rsi
	movq %rcx,%rdx
	movq %r8,%r10
	movq %r9,%r8
	movq 8(%rsp),%r9
	syscall
	ret