helper.c

qemu虚拟机代码

    den = T0;
    if (den == 0) {
        raise_exception(EXCP00_DIVZ);
    }
#ifdef BUGGY_GCC_DIV64
    r = div32(&q, num, den);
#else
    q = (num / den);
    r = (num % den);
#endif
    if (q > 0xffffffff)
        raise_exception(EXCP00_DIVZ);
    EAX = (uint32_t)q;
    EDX = (uint32_t)r;
}

void helper_idivl_EAX_T0(void)
{
    int den, r;
    int64_t num, q;
    
    num = ((uint32_t)EAX) | ((uint64_t)((uint32_t)EDX) << 32);
    den = T0;
    if (den == 0) {
        raise_exception(EXCP00_DIVZ);
    }
#ifdef BUGGY_GCC_DIV64
    r = idiv32(&q, num, den);
#else
    q = (num / den);
    r = (num % den);
#endif
    if (q != (int32_t)q)
        raise_exception(EXCP00_DIVZ);
    EAX = (uint32_t)q;
    EDX = (uint32_t)r;
}

void helper_cmpxchg8b(void)
{
    uint64_t d;
    int eflags;

    eflags = cc_table[CC_OP].compute_all();
    d = ldq(A0);
    if (d == (((uint64_t)EDX << 32) | EAX)) {
        stq(A0, ((uint64_t)ECX << 32) | EBX);
        eflags |= CC_Z;
    } else {
        EDX = d >> 32;
        EAX = d;
        eflags &= ~CC_Z;
    }
    CC_SRC = eflags;
}

void helper_cpuid(void)
{
    uint32_t index;
    index = (uint32_t)EAX;
    
    /* test if maximum index reached */
    if (index & 0x80000000) {
        if (index > env->cpuid_xlevel) 
            index = env->cpuid_level;
    } else {
        if (index > env->cpuid_level) 
            index = env->cpuid_level;
    }
        
    switch(index) {
    case 0:
        EAX = env->cpuid_level;
        EBX = env->cpuid_vendor1;
        EDX = env->cpuid_vendor2;
        ECX = env->cpuid_vendor3;
        break;
    case 1:
        EAX = env->cpuid_version;
        EBX = 8 << 8; /* CLFLUSH size in quad words, Linux wants it. */
        ECX = env->cpuid_ext_features;
        EDX = env->cpuid_features;
        break;
    case 2:
        /* cache info: needed for Pentium Pro compatibility */
        EAX = 0x410601;
        EBX = 0;
        ECX = 0;
        EDX = 0;
        break;
    case 0x80000000:
        EAX = env->cpuid_xlevel;
        EBX = env->cpuid_vendor1;
        EDX = env->cpuid_vendor2;
        ECX = env->cpuid_vendor3;
        break;
    case 0x80000001:
        EAX = env->cpuid_features;
        EBX = 0;
        ECX = 0;
        EDX = env->cpuid_ext2_features;
        break;
    case 0x80000002:
    case 0x80000003:
    case 0x80000004:
        EAX = env->cpuid_model[(index - 0x80000002) * 4 + 0];
        EBX = env->cpuid_model[(index - 0x80000002) * 4 + 1];
        ECX = env->cpuid_model[(index - 0x80000002) * 4 + 2];
        EDX = env->cpuid_model[(index - 0x80000002) * 4 + 3];
        break;
    case 0x80000005:
        /* cache info (L1 cache) */
        EAX = 0x01ff01ff;
        EBX = 0x01ff01ff;
        ECX = 0x40020140;
        EDX = 0x40020140;
        break;
    case 0x80000006:
        /* cache info (L2 cache) */
        EAX = 0;
        EBX = 0x42004200;
        ECX = 0x02008140;
        EDX = 0;
        break;
    case 0x80000008:
        /* virtual & phys address size in low 2 bytes. */
        EAX = 0x00003028;
        EBX = 0;
        ECX = 0;
        EDX = 0;
        break;
    default:
        /* reserved values: zero */
        EAX = 0;
        EBX = 0;
        ECX = 0;
        EDX = 0;
        break;
    }
}

void helper_enter_level(int level, int data32)
{
    target_ulong ssp;
    uint32_t esp_mask, esp, ebp;

    esp_mask = get_sp_mask(env->segs[R_SS].flags);
    ssp = env->segs[R_SS].base;
    ebp = EBP;
    esp = ESP;
    if (data32) {
        /* 32 bit */
        esp -= 4;
        while (--level) {
            esp -= 4;
            ebp -= 4;
            stl(ssp + (esp & esp_mask), ldl(ssp + (ebp & esp_mask)));
        }
        esp -= 4;
        stl(ssp + (esp & esp_mask), T1);
    } else {
        /* 16 bit */
        esp -= 2;
        while (--level) {
            esp -= 2;
            ebp -= 2;
            stw(ssp + (esp & esp_mask), lduw(ssp + (ebp & esp_mask)));
        }
        esp -= 2;
        stw(ssp + (esp & esp_mask), T1);
    }
}

#ifdef TARGET_X86_64
void helper_enter64_level(int level, int data64)
{
    target_ulong esp, ebp;
    ebp = EBP;
    esp = ESP;

    if (data64) {
        /* 64 bit */
        esp -= 8;
        while (--level) {
            esp -= 8;
            ebp -= 8;
            stq(esp, ldq(ebp));
        }
        esp -= 8;
        stq(esp, T1);
    } else {
        /* 16 bit */
        esp -= 2;
        while (--level) {
            esp -= 2;
            ebp -= 2;
            stw(esp, lduw(ebp));
        }
        esp -= 2;
        stw(esp, T1);
    }
}
#endif

void helper_lldt_T0(void)
{
    int selector;
    SegmentCache *dt;
    uint32_t e1, e2;
    int index, entry_limit;
    target_ulong ptr;
    
    selector = T0 & 0xffff;
    if ((selector & 0xfffc) == 0) {
        /* XXX: NULL selector case: invalid LDT */
        env->ldt.base = 0;
        env->ldt.limit = 0;
    } else {
        if (selector & 0x4)
            raise_exception_err(EXCP0D_GPF, selector & 0xfffc);
        dt = &env->gdt;
        index = selector & ~7;
#ifdef TARGET_X86_64
        if (env->hflags & HF_LMA_MASK)
            entry_limit = 15;
        else
#endif            
            entry_limit = 7;
        if ((index + entry_limit) > dt->limit)
            raise_exception_err(EXCP0D_GPF, selector & 0xfffc);
        ptr = dt->base + index;
        e1 = ldl_kernel(ptr);
        e2 = ldl_kernel(ptr + 4);
        if ((e2 & DESC_S_MASK) || ((e2 >> DESC_TYPE_SHIFT) & 0xf) != 2)
            raise_exception_err(EXCP0D_GPF, selector & 0xfffc);
        if (!(e2 & DESC_P_MASK))
            raise_exception_err(EXCP0B_NOSEG, selector & 0xfffc);
#ifdef TARGET_X86_64
        if (env->hflags & HF_LMA_MASK) {
            uint32_t e3;
            e3 = ldl_kernel(ptr + 8);
            load_seg_cache_raw_dt(&env->ldt, e1, e2);
            env->ldt.base |= (target_ulong)e3 << 32;
        } else
#endif
        {
            load_seg_cache_raw_dt(&env->ldt, e1, e2);
        }
    }
    env->ldt.selector = selector;
}

void helper_ltr_T0(void)
{
    int selector;
    SegmentCache *dt;
    uint32_t e1, e2;
    int index, type, entry_limit;
    target_ulong ptr;
    
    selector = T0 & 0xffff;
    if ((selector & 0xfffc) == 0) {
        /* NULL selector case: invalid TR */
        env->tr.base = 0;
        env->tr.limit = 0;
        env->tr.flags = 0;
    } else {
        if (selector & 0x4)
            raise_exception_err(EXCP0D_GPF, selector & 0xfffc);
        dt = &env->gdt;
        index = selector & ~7;
#ifdef TARGET_X86_64
        if (env->hflags & HF_LMA_MASK)
            entry_limit = 15;
        else
#endif            
            entry_limit = 7;
        if ((index + entry_limit) > dt->limit)
            raise_exception_err(EXCP0D_GPF, selector & 0xfffc);
        ptr = dt->base + index;
        e1 = ldl_kernel(ptr);
        e2 = ldl_kernel(ptr + 4);
        type = (e2 >> DESC_TYPE_SHIFT) & 0xf;
        if ((e2 & DESC_S_MASK) || 
            (type != 1 && type != 9))
            raise_exception_err(EXCP0D_GPF, selector & 0xfffc);
        if (!(e2 & DESC_P_MASK))
            raise_exception_err(EXCP0B_NOSEG, selector & 0xfffc);
#ifdef TARGET_X86_64
        if (env->hflags & HF_LMA_MASK) {
            uint32_t e3;
            e3 = ldl_kernel(ptr + 8);
            load_seg_cache_raw_dt(&env->tr, e1, e2);
            env->tr.base |= (target_ulong)e3 << 32;
        } else 
#endif
        {
            load_seg_cache_raw_dt(&env->tr, e1, e2);
        }
        e2 |= DESC_TSS_BUSY_MASK;
        stl_kernel(ptr + 4, e2);
    }
    env->tr.selector = selector;
}

/* only works if protected mode and not VM86. seg_reg must be != R_CS */
void load_seg(int seg_reg, int selector)
{
    uint32_t e1, e2;
    int cpl, dpl, rpl;
    SegmentCache *dt;
    int index;
    target_ulong ptr;

    selector &= 0xffff;
    cpl = env->hflags & HF_CPL_MASK;
    if ((selector & 0xfffc) == 0) {
        /* null selector case */
        if (seg_reg == R_SS
#ifdef TARGET_X86_64
            && (!(env->hflags & HF_CS64_MASK) || cpl == 3)
#endif
            )
            raise_exception_err(EXCP0D_GPF, 0);
        cpu_x86_load_seg_cache(env, seg_reg, selector, 0, 0, 0);
    } else {
        
        if (selector & 0x4)
            dt = &env->ldt;
        else
            dt = &env->gdt;
        index = selector & ~7;
        if ((index + 7) > dt->limit)
            raise_exception_err(EXCP0D_GPF, selector & 0xfffc);
        ptr = dt->base + index;
        e1 = ldl_kernel(ptr);
        e2 = ldl_kernel(ptr + 4);
        
        if (!(e2 & DESC_S_MASK))
            raise_exception_err(EXCP0D_GPF, selector & 0xfffc);
        rpl = selector & 3;
        dpl = (e2 >> DESC_DPL_SHIFT) & 3;
        if (seg_reg == R_SS) {
            /* must be writable segment */
            if ((e2 & DESC_CS_MASK) || !(e2 & DESC_W_MASK))
                raise_exception_err(EXCP0D_GPF, selector & 0xfffc);
            if (rpl != cpl || dpl != cpl)
                raise_exception_err(EXCP0D_GPF, selector & 0xfffc);
        } else {
            /* must be readable segment */
            if ((e2 & (DESC_CS_MASK | DESC_R_MASK)) == DESC_CS_MASK)
                raise_exception_err(EXCP0D_GPF, selector & 0xfffc);
            
            if (!(e2 & DESC_CS_MASK) || !(e2 & DESC_C_MASK)) {
                /* if not conforming code, test rights */
                if (dpl < cpl || dpl < rpl) 
                    raise_exception_err(EXCP0D_GPF, selector & 0xfffc);
            }
        }

        if (!(e2 & DESC_P_MASK)) {
            if (seg_reg == R_SS)
                raise_exception_err(EXCP0C_STACK, selector & 0xfffc);
            else
                raise_exception_err(EXCP0B_NOSEG, selector & 0xfffc);
        }

        /* set the access bit if not already set */
        if (!(e2 & DESC_A_MASK)) {
            e2 |= DESC_A_MASK;
            stl_kernel(ptr + 4, e2);
        }

        cpu_x86_load_seg_cache(env, seg_reg, selector, 
                       get_seg_base(e1, e2),
                       get_seg_limit(e1, e2),
                       e2);
#if 0
        fprintf(logfile, "load_seg: sel=0x%04x base=0x%08lx limit=0x%08lx flags=%08x\n", 
                selector, (unsigned long)sc->base, sc->limit, sc->flags);
#endif
    }
}

/* protected mode jump */
void helper_ljmp_protected_T0_T1(int next_eip_addend)
{
    int new_cs, gate_cs, type;
    uint32_t e1, e2, cpl, dpl, rpl, limit;
    target_ulong new_eip, next_eip;
    
    new_cs = T0;
    new_eip = T1;
    if ((new_cs & 0xfffc) == 0)
        raise_exception_err(EXCP0D_GPF, 0);
    if (load_segment(&e1, &e2, new_cs) != 0)
        raise_exception_err(EXCP0D_GPF, new_cs & 0xfffc);
    cpl = env->hflags & HF_CPL_MASK;
    if (e2 & DESC_S_MASK) {
        if (!(e2 & DESC_CS_MASK))
            raise_exception_err(EXCP0D_GPF, new_cs & 0xfffc);
        dpl = (e2 >> DESC_DPL_SHIFT) & 3;
        if (e2 & DESC_C_MASK) {
            /* conforming code segment */
            if (dpl > cpl)
                raise_exception_err(EXCP0D_GPF, new_cs & 0xfffc);
        } else {
            /* non conforming code segment */
            rpl = new_cs & 3;
            if (rpl > cpl)
                raise_exception_err(EXCP0D_GPF, new_cs & 0xfffc);
            if (dpl != cpl)
                raise_exception_err(EXCP0D_GPF, new_cs & 0xfffc);