system.h

fairysky系统,是一个小型的内核,模拟linux原始版本的

/*文件名: system.h
  说明:   系统指令接口
  作者:   Linus Torvalds
  日期:   2005/12/20
*/

#define move_to_user_mode(esp) \
	__asm__ __volatile__ (    \
        "pushl $0x23\n\t" \
        "pushl %%eax\n\t" \
        "pushfl\n\t" \
        "pushl $0x1B\n\t" \
        "pushl $1f\n\t" \
        "iret\n" \
        "1:\tmovl $0x23, %%eax\n\t" \
        "mov %%ax,%%ds\n\t" \
        "mov %%ax,%%es\n\t" \
        "mov %%ax,%%fs\n\t" \
        "mov %%ax,%%gs" \
        ::"a"(esp)    \
        )

    
#define sti() __asm__ __volatile__ ("sti"::)
#define cli() __asm__ __volatile__ ("cli"::)
#define nop() __asm__ __volatile__ ("nop"::)

#define iret() __asm__ __volatile__ ("iret"::)

/*#define _set_gate(gate_addr,type,dpl,addr) \
__asm__ __volatile__ ("movw %%dx,%%ax\n\t" \
    "movw %0,%%dx\n\t" \
    "movl %%eax,%1\n\t" \
    "movl %%edx,%2" \
    :: "i" ((short) (0x8000+(dpl<<13)+(type<<8))), \
    "m" (*((char *) (gate_addr))), \
    "m" (*(4+(char *) (gate_addr))), \
    "d" ((char *) (addr)),"a" (0x00080000) \
    :"ax","dx")

#define set_intr_gate(n,addr) \
    _set_gate(&idt[n],14,0,addr)

#define set_trap_gate(n,addr) \
    _set_gate(&idt[n],15,0,addr)

#define set_system_gate(n,addr) \
    _set_gate(&idt[n],15,3,addr)
*/
#define _set_seg_desc(gate_addr,type,dpl,base,limit) {\
    *(gate_addr) = ((base) & 0xff000000) | \
        (((base) & 0x00ff0000)>>16) | \
        ((limit) & 0xf0000) | \
        ((dpl)<<13) | \
        (0x00408000) | \
        ((type)<<8); \
    *((gate_addr)+1) = (((base) & 0x0000ffff)<<16) | \
        ((limit) & 0x0ffff); }

#define _set_tssldt_desc(n,addr,type) \
__asm__ __volatile__ ("movw $232,%1\n\t" \
    "movw %%ax,%2\n\t" \
    "rorl $16,%%eax\n\t" \
    "movb %%al,%3\n\t" \
    "movb $" type ",%4\n\t" \
    "movb $0x00,%5\n\t" \
    "movb %%ah,%6\n\t" \
    "rorl $16,%%eax" \
    ::"a" (addr), "m" (*(n)), "m" (*(n+2)), "m" (*(n+4)), \
     "m" (*(n+5)), "m" (*(n+6)), "m" (*(n+7)) \
    )


#define set_tss_desc(n,addr) _set_tssldt_desc(((char *) (n)),addr, "0x89")
#define set_ldt_desc(n,addr) _set_tssldt_desc(((char *) (n)),addr, "0x82")

#define lidt(_idt)  \
    __asm__ __volatile__ ( \
        "lidtl  (%%ebx)" \
        :   \
        :"b"(_idt)  \
        )

#define load_fs(value) \
    __asm__ __volatile__( \
        "movw     %%ax, %%fs\n\t" \
        ::"a" (value) \
        )

#define load_gs(value) \
    __asm__ __volatile__( \
        "movw     %%ax, %%gs\n\t" \
        ::"a" (value) \
        )

#define ltr(value) \
    __asm__ __volatile__( \
        "ltrw     %%ax\n\t" \
        ::"a" (value) \
        )

#define lldt(value) \
    __asm__ __volatile__( \
        "lldtw     %%ax\n\t" \
        ::"a" (value) \
        )

#define lgdt(_idt)  \
    __asm__ __volatile__ ( \
        "lgdtl  (%%ebx)" \
        :   \
        :"b"(_idt)  \
        )