xv6-65oo2/x86.h

static __inline uchar
inb(int port)
{
	uchar data;
	__asm __volatile("inb %w1,%0" : "=a" (data) : "d" (port));
	return data;
}

static __inline void
insl(int port, void *addr, int cnt)
{
	__asm __volatile("cld\n\trepne\n\tinsl"			:
			 "=D" (addr), "=c" (cnt)		:
			 "d" (port), "0" (addr), "1" (cnt)	:
			 "memory", "cc");
}

static __inline void
outb(int port, uchar data)
{
	__asm __volatile("outb %0,%w1" : : "a" (data), "d" (port));
}

static __inline void
outw(int port, ushort data)
{
	__asm __volatile("outw %0,%w1" : : "a" (data), "d" (port));
}

static __inline void
outsl(int port, const void *addr, int cnt)
{
	__asm __volatile("cld\n\trepne\n\toutsl"		:
			 "=S" (addr), "=c" (cnt)		:
			 "d" (port), "0" (addr), "1" (cnt)	:
			 "cc");
}

struct segdesc;

static __inline void
lgdt(struct segdesc *p, int size)
{
	volatile ushort pd[3];
  
	pd[0] = size-1;
	pd[1] = (uint)p;
	pd[2] = (uint)p >> 16;

	asm volatile("lgdt (%0)" : : "g" (pd));
}

struct gatedesc;

static __inline void
lidt(struct gatedesc *p, int size)
{
	volatile ushort pd[3];
  
	pd[0] = size-1;
	pd[1] = (uint)p;
	pd[2] = (uint)p >> 16;
  
	asm volatile("lidt (%0)" : : "g" (pd));
}

static __inline void
ltr(ushort sel)
{
	__asm __volatile("ltr %0" : : "r" (sel));
}

static __inline uint
read_eflags(void)
{
        uint eflags;
        __asm __volatile("pushfl; popl %0" : "=r" (eflags));
        return eflags;
}

static __inline void
write_eflags(uint eflags)
{
        __asm __volatile("pushl %0; popfl" : : "r" (eflags));
}

static __inline void
cpuid(uint info, uint *eaxp, uint *ebxp, uint *ecxp, uint *edxp)
{
	uint eax, ebx, ecx, edx;
	asm volatile("cpuid" 
		: "=a" (eax), "=b" (ebx), "=c" (ecx), "=d" (edx)
		: "a" (info));
	if (eaxp)
		*eaxp = eax;
	if (ebxp)
		*ebxp = ebx;
	if (ecxp)
		*ecxp = ecx;
	if (edxp)
		*edxp = edx;
}

static __inline uint
cmpxchg(uint oldval, uint newval, volatile uint* lock_addr)
{
  uint result;
  __asm__ __volatile__(
		       "lock; cmpxchgl %2, %0"
		       :"+m" (*lock_addr), "=a" (result) : "r"(newval), "1"(oldval) : "cc"
		       );
  return result;
}

static __inline void
cli(void)
{
	__asm__ volatile("cli");
}

static __inline void
sti(void)
{
	__asm__ volatile("sti");
}

struct trapframe {
    /* registers as pushed by pusha */
    uint edi;
    uint esi;
    uint ebp;
    uint oesp;      /* Useless */
    uint ebx;
    uint edx;
    uint ecx;
    uint eax;
    /* rest of trap frame */
    ushort es;
    ushort padding1;
    ushort ds;
    ushort padding2;
    uint trapno;
    /* below here defined by x86 hardware */
    uint err;
    uint eip;
    ushort cs;
    ushort padding3;
    uint eflags;
    /* below here only when crossing rings, such as from user to kernel */
    uint esp;
    ushort ss;
    ushort padding4;
};