160 lines
2.7 KiB
C
160 lines
2.7 KiB
C
// Routines to let C code use special x86 instructions.
|
|
|
|
static inline uchar
|
|
inb(ushort port)
|
|
{
|
|
uchar data;
|
|
|
|
asm volatile("in %1,%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(ushort port, uchar data)
|
|
{
|
|
asm volatile("out %0,%1" : : "a" (data), "d" (port));
|
|
}
|
|
|
|
static inline void
|
|
outw(ushort port, ushort data)
|
|
{
|
|
asm volatile("out %0,%1" : : "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");
|
|
}
|
|
|
|
static inline uint
|
|
read_ebp(void)
|
|
{
|
|
uint ebp;
|
|
|
|
asm volatile("movl %%ebp, %0" : "=a" (ebp));
|
|
return ebp;
|
|
}
|
|
|
|
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)" : : "r" (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)" : : "r" (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 uint
|
|
xchg(volatile uint *addr, uint newval)
|
|
{
|
|
uint result;
|
|
|
|
// The + in "+m" denotes a read-modify-write operand.
|
|
asm volatile("lock; xchgl %0, %1" :
|
|
"+m" (*addr), "=a" (result) :
|
|
"1" (newval) :
|
|
"cc");
|
|
return result;
|
|
}
|
|
|
|
static inline void
|
|
cli(void)
|
|
{
|
|
asm volatile("cli");
|
|
}
|
|
|
|
static inline void
|
|
sti(void)
|
|
{
|
|
asm volatile("sti");
|
|
}
|
|
|
|
// Layout of the trap frame built on the stack by the
|
|
// hardware and by trapasm.S, and passed to trap().
|
|
struct trapframe {
|
|
// registers as pushed by pusha
|
|
uint edi;
|
|
uint esi;
|
|
uint ebp;
|
|
uint oesp; // useless & ignored
|
|
uint ebx;
|
|
uint edx;
|
|
uint ecx;
|
|
uint eax;
|
|
|
|
// rest of trap frame
|
|
ushort gs;
|
|
ushort padding1;
|
|
ushort fs;
|
|
ushort padding2;
|
|
ushort es;
|
|
ushort padding3;
|
|
ushort ds;
|
|
ushort padding4;
|
|
uint trapno;
|
|
|
|
// below here defined by x86 hardware
|
|
uint err;
|
|
uint eip;
|
|
ushort cs;
|
|
ushort padding5;
|
|
uint eflags;
|
|
|
|
// below here only when crossing rings, such as from user to kernel
|
|
uint esp;
|
|
ushort ss;
|
|
ushort padding6;
|
|
};
|