musl/arch/i386/syscall_arch.h

#define __SYSCALL_LL_E(x) \
((union { long long ll; long l[2]; }){ .ll = x }).l[0], \
((union { long long ll; long l[2]; }){ .ll = x }).l[1]
#define __SYSCALL_LL_O(x) __SYSCALL_LL_E((x))

#define __SYSCALL_SSLEN 8

static inline long __syscall0(long n)
{
	unsigned long __ret;
	__asm__ __volatile__ ("call __vsyscall" : "=a"(__ret) : "a"(n) : "memory");
	return __ret;
}

static inline long __syscall1(long n, long a1)
{
	unsigned long __ret;
	__asm__ __volatile__ ("call __vsyscall" : "=a"(__ret) : "a"(n), "d"(a1) : "memory");
	return __ret;
}

static inline long __syscall2(long n, long a1, long a2)
{
	unsigned long __ret;
	__asm__ __volatile__ ("call __vsyscall" : "=a"(__ret) : "a"(n), "d"(a1), "c"(a2) : "memory");
	return __ret;
}

static inline long __syscall3(long n, long a1, long a2, long a3)
{
	unsigned long __ret;
	__asm__ __volatile__ ("call __vsyscall" : "=a"(__ret) : "a"(n), "d"(a1), "c"(a2), "D"(a3) : "memory");
	return __ret;
}

static inline long __syscall4(long n, long a1, long a2, long a3, long a4)
{
	unsigned long __ret;
	__asm__ __volatile__ ("call __vsyscall" : "=a"(__ret) : "a"(n), "d"(a1), "c"(a2), "D"(a3), "S"(a4) : "memory");
	return __ret;
}

static inline long __syscall5(long n, long a1, long a2, long a3, long a4, long a5)
{
	unsigned long __ret;
	__asm__ __volatile__ ("push %6 ; call __vsyscall ; add $4,%%esp" : "=a"(__ret) : "a"(n), "d"(a1), "c"(a2), "D"(a3), "S"(a4), "g"(a5) : "memory");
	return __ret;
}

static inline long __syscall6(long n, long a1, long a2, long a3, long a4, long a5, long a6)
{
	unsigned long __ret;
	__asm__ __volatile__ ("push %6 ; call __vsyscall6 ; add $4,%%esp" : "=a"(__ret) : "a"(n), "d"(a1), "c"(a2), "D"(a3), "S"(a4), "g"(0+(long[]){a5, a6}) : "memory");
	return __ret;
}


#define __SC_socket      1
#define __SC_bind        2
#define __SC_connect     3
#define __SC_listen      4
#define __SC_accept      5
#define __SC_getsockname 6
#define __SC_getpeername 7
#define __SC_socketpair  8
#define __SC_send        9
#define __SC_recv        10
#define __SC_sendto      11
#define __SC_recvfrom    12
#define __SC_shutdown    13
#define __SC_setsockopt  14
#define __SC_getsockopt  15
#define __SC_sendmsg     16
#define __SC_recvmsg     17
#define __SC_accept4     18
#define __SC_recvmmsg    19
#define __SC_sendmmsg    20