Bochs/bochs/cpu/cpuid.cc

/////////////////////////////////////////////////////////////////////////
// $Id: cpuid.cc,v 1.89 2010-02-25 22:04:30 sshwarts Exp $
/////////////////////////////////////////////////////////////////////////
//
//   Copyright (c) 2007-2009 Stanislav Shwartsman
//          Written by Stanislav Shwartsman [sshwarts at sourceforge net]
//
//  This library is free software; you can redistribute it and/or
//  modify it under the terms of the GNU Lesser General Public
//  License as published by the Free Software Foundation; either
//  version 2 of the License, or (at your option) any later version.
//
//  This library is distributed in the hope that it will be useful,
//  but WITHOUT ANY WARRANTY; without even the implied warranty of
//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
//  Lesser General Public License for more details.
//
//  You should have received a copy of the GNU Lesser General Public
//  License along with this library; if not, write to the Free Software
//  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA B 02110-1301 USA
//
/////////////////////////////////////////////////////////////////////////

#define NEED_CPU_REG_SHORTCUTS 1
#include "bochs.h"
#include "cpu.h"
#define LOG_THIS BX_CPU_THIS_PTR

#if BX_SUPPORT_X86_64==0
// Make life easier for merging code.
#define RAX EAX
#define RBX EBX
#define RCX ECX
#define RDX EDX
#endif

/* Get CPU version information. */
Bit32u BX_CPU_C::get_cpu_version_information(void)
{
  Bit32u family = 0, model = 0, stepping = 0;
  Bit32u extended_model = 0;
  Bit32u extended_family = 0;

#if BX_CPU_LEVEL > 3

  /* ****** */
  /*  i486  */
  /* ****** */

#if BX_CPU_LEVEL == 4
  family = 4;

#if BX_SUPPORT_FPU
  model = 1;            // 486dx
  stepping = 3;
#else
  model = 2;            // 486sx
  stepping = 3;
#endif

  /* **************** */
  /*  i586 (Pentium)  */
  /* **************** */

#elif BX_CPU_LEVEL == 5	
  family   = 5;
#if BX_SUPPORT_MMX
  model    = 4;         // Pentium MMX
#else
  model    = 1;         // Pentium 60/66
#endif
  stepping = 3;

  /* ****** */
  /*  i686  */
  /* ****** */

#elif BX_CPU_LEVEL == 6

  unsigned sse_enabled = SIM->get_param_enum(BXPN_CPUID_SSE)->get();

  if (sse_enabled >= 2) {

/*
     The model, family, and processor type for the first
     processor in the Intel Pentium 4 family is as follows:
		* Model-0000B
		* Family-1111B
		* Processor Type-00B (OEM)
                * Stepping-0B
*/
    model    = 0;
    family   = 0xf;
    stepping = 0;

#if BX_SUPPORT_X86_64
    model    = 2;       // Hammer returns what?
#endif

  }
  else {                // Pentium Pro/Pentium II/Pentium III processor
    family   = 6;
    model    = 8;
    stepping = 3;
  }

#else
  BX_PANIC(("CPUID family ID not implemented for CPU LEVEL > 6"));
#endif

#endif  // BX_CPU_LEVEL > 3

  return (extended_family << 20) |
         (extended_model << 16) |
         (family << 8) |
         (model<<4) | stepping;
}

/* Get CPU extended feature flags. */
Bit32u BX_CPU_C::get_extended_cpuid_features(void)
{
  // [0:0]   SSE3: SSE3 Instructions
  // [1:1]   PCLMULQDQ Instruction support
  // [2:2]   reserved
  // [3:3]   MONITOR/MWAIT support
  // [4:4]   DS-CPL: CPL qualified debug store
  // [5:5]   VMX: Virtual Machine Technology
  // [6:6]   SMX: Secure Virtual Machine Technology
  // [7:7]   EST: Enhanced Intel SpeedStep Technology
  // [8:8]   TM2: Thermal Monitor 2
  // [9:9]   SSE3E: SSE3E Instructions (Intel Core Duo 2 new instructions)
  // [10:10] CNXT-ID: L1 context ID
  // [11:11] reserved
  // [12:12] FMA Instructions support
  // [13:13] CMPXCHG16B: CMPXCHG16B instruction support
  // [14:14] xTPR update control
  // [17:15] reserved
  // [18:18] DCA - Direct Cache Access
  // [19:19] SSE4.1 Instructions
  // [20:20] SSE4.2 Instructions
  // [21:21] X2APIC
  // [22:22] MOVBE instruction
  // [23:23] POPCNT instruction
  // [24:24] reserved
  // [25:25] AES Instructions
  // [26:26] XSAVE extensions support
  // [27:27] OSXSAVE support
  // [28:28] AVX extensions support
  // [31:29] reserved

  Bit32u features = 0;

  // support SSE3
  if (BX_CPU_THIS_PTR cpuid_features_bitmask & BX_CPU_SSE3)
    features |= (1<<0);

  if (BX_CPU_THIS_PTR cpuid_features_bitmask & BX_CPU_PCLMULQDQ)
    features |= (1<<1);

  if (BX_CPU_THIS_PTR cpuid_features_bitmask & BX_CPU_MONITOR_MWAIT)
    features |= (1<<3);

  if (BX_CPU_THIS_PTR cpuid_features_bitmask & BX_CPU_VMX)
    features |= (1<<5);

  if (BX_CPU_THIS_PTR cpuid_features_bitmask & BX_CPU_SSSE3)
    features |= (1<<9);

#if BX_SUPPORT_X86_64
  // support CMPXCHG16B
  if (BX_CPU_THIS_PTR cpuid_features_bitmask & BX_CPU_X86_64)
    features |= (1<<13);
#endif

  if (BX_CPU_THIS_PTR cpuid_features_bitmask & BX_CPU_SSE4_1)
    features |= (1<<19);

  if (BX_CPU_THIS_PTR cpuid_features_bitmask & BX_CPU_SSE4_2)
    features |= (1<<20);

  if (BX_CPU_THIS_PTR cpuid_features_bitmask & BX_CPU_MOVBE)
    features |= (1<<22);

  // enable POPCNT if SSE4_2 is enabled
  if (BX_CPU_THIS_PTR cpuid_features_bitmask & BX_CPU_SSE4_2)
    features |= (1<<23);

  if (BX_CPU_THIS_PTR cpuid_features_bitmask & BX_CPU_AES)
    features |= (1<<25);

  // support XSAVE extensions
  if (BX_CPU_THIS_PTR cpuid_features_bitmask & BX_CPU_XSAVE)
    features |= (1<<26) | (1<<27);

  return features;
}

/* Get CPU feature flags. Returned by CPUID functions 1 and 80000001.  */
Bit32u BX_CPU_C::get_std_cpuid_features(void)
{
  //   [0:0]   FPU on chip
  //   [1:1]   VME: Virtual-8086 Mode enhancements
  //   [2:2]   DE: Debug Extensions (I/O breakpoints)
  //   [3:3]   PSE: Page Size Extensions
  //   [4:4]   TSC: Time Stamp Counter
  //   [5:5]   MSR: RDMSR and WRMSR support
  //   [6:6]   PAE: Physical Address Extensions
  //   [7:7]   MCE: Machine Check Exception
  //   [8:8]   CXS: CMPXCHG8B instruction
  //   [9:9]   APIC: APIC on Chip
  //   [10:10] Reserved
  //   [11:11] SYSENTER/SYSEXIT support
  //   [12:12] MTRR: Memory Type Range Reg
  //   [13:13] PGE/PTE Global Bit
  //   [14:14] MCA: Machine Check Architecture
  //   [15:15] CMOV: Cond Mov/Cmp Instructions
  //   [16:16] PAT: Page Attribute Table
  //   [17:17] PSE-36: Physical Address Extensions
  //   [18:18] Processor Serial Number
  //   [19:19] CLFLUSH: CLFLUSH Instruction support
  //   [20:20] Reserved
  //   [21:21] DS: Debug Store
  //   [22:22] ACPI: Thermal Monitor and Software Controlled Clock Facilities
  //   [23:23] MMX Technology
  //   [24:24] FXSR: FXSAVE/FXRSTOR (also indicates CR4.OSFXSR is available)
  //   [25:25] SSE: SSE Extensions
  //   [26:26] SSE2: SSE2 Extensions
  //   [27:27] Reserved
  //   [28:28] Hyper Threading Technology
  //   [29:29] TM: Thermal Monitor
  //   [30:30] Reserved
  //   [31:31] PBE: Pending Break Enable

  Bit32u features = 0;

  if (BX_CPU_THIS_PTR cpuid_features_bitmask & BX_CPU_X87)
    features |= (1<<0);

#if BX_CPU_LEVEL >= 5
  if (BX_CPU_THIS_PTR cpuid_features_bitmask & BX_CPU_PENTIUM) {
    // Pentium only features
    features |= (1<<1);
    features |= (1<<3);             // support PSE
    features |= (1<<4);             // support Time Stamp Counter
    features |= (1<<5);             // support RDMSR/WRMSR
    features |= (1<<7) | (1<<14);   // support Machine Check
    features |= (1<<8);             // support CMPXCHG8B instruction
  }
#endif

  features |= (1<<2);   // support Debug Extensions

#if BX_SUPPORT_APIC
  // if MSR_APICBASE APIC Global Enable bit has been cleared,
  // the CPUID feature flag for the APIC is set to 0.
  if (BX_CPU_THIS_PTR msr.apicbase & 0x800)
    features |= (1<<9); // APIC on chip
#endif

  if (BX_CPU_THIS_PTR cpuid_features_bitmask & BX_CPU_SYSENTER_SYSEXIT)
    features |= (1<<11);

  if (BX_CPU_THIS_PTR cpuid_features_bitmask & BX_CPU_CLFLUSH)
    features |= (1<<19);

  if (BX_CPU_THIS_PTR cpuid_features_bitmask & BX_CPU_MMX)
    features |= (1<<23);

#if BX_CPU_LEVEL >= 6
  if (BX_CPU_THIS_PTR cpuid_features_bitmask & BX_CPU_P6) {
    features |= (1<<15);  // Implement CMOV instructions
    features |= (1<<24);  // Implement FSAVE/FXRSTOR instructions
    features |= (1<<6);   // support PAE
    features |= (1<<12);  // support MTRRs
    features |= (1<<13);  // support Global pages
    features |= (1<<16);  // support PAT
    features |= (1<<17);  // support PSE-36
  }

  if (BX_CPU_THIS_PTR cpuid_features_bitmask & BX_CPU_SSE)
    features |= (1<<25);

  if (BX_CPU_THIS_PTR cpuid_features_bitmask & BX_CPU_SSE2)
    features |= (1<<26);
#endif

#if BX_SUPPORT_SMP
  // Intel(R) HyperThreading Technology
  if (SIM->get_param_num(BXPN_CPU_NTHREADS)->get() > 1)
    features |= (1<<28);
#endif

  return features;
}

void BX_CPP_AttrRegparmN(1) BX_CPU_C::CPUID(bxInstruction_c *i)
{
#if BX_CPU_LEVEL >= 4
  Bit32u function    = EAX;
#if BX_SUPPORT_XSAVE
  Bit32u subfunction = ECX;
#endif

#if BX_SUPPORT_VMX
  if (BX_CPU_THIS_PTR in_vmx_guest) {
    BX_ERROR(("VMEXIT: CPUID in VMX non-root operation"));
    VMexit(i, VMX_VMEXIT_CPUID, 0);
  }
#endif

  if(function < 0x80000000) {
    if(function < MAX_STD_CPUID_FUNCTION) {
      RAX = BX_CPU_THIS_PTR cpuid_std_function[function].eax;
      RBX = BX_CPU_THIS_PTR cpuid_std_function[function].ebx;
      RCX = BX_CPU_THIS_PTR cpuid_std_function[function].ecx;
      RDX = BX_CPU_THIS_PTR cpuid_std_function[function].edx;
#if BX_SUPPORT_APIC
      if (function == 1) {
        // if MSR_APICBASE APIC Global Enable bit has been cleared,
        // the CPUID feature flag for the APIC is set to 0.
        if ((BX_CPU_THIS_PTR msr.apicbase & 0x800) == 0)
          RDX &= ~(1<<9); // APIC on chip
      }
#endif
#if BX_SUPPORT_XSAVE
      if (function == 0xD && subfunction > 0) {
        RAX = 0;
        RBX = 0;
        RCX = 0;
        RDX = 0;
      }
#endif
      return;
    }
  }
  else {
    function -= 0x80000000;
    if(function < MAX_EXT_CPUID_FUNCTION) {
      RAX = BX_CPU_THIS_PTR cpuid_ext_function[function].eax;
      RBX = BX_CPU_THIS_PTR cpuid_ext_function[function].ebx;
      RCX = BX_CPU_THIS_PTR cpuid_ext_function[function].ecx;
      RDX = BX_CPU_THIS_PTR cpuid_ext_function[function].edx;
#if BX_SUPPORT_APIC
      if (function == 1) {
        // if MSR_APICBASE APIC Global Enable bit has been cleared,
        // the CPUID feature flag for the APIC is set to 0.
        if ((BX_CPU_THIS_PTR msr.apicbase & 0x800) == 0)
          RDX &= ~(1<<9); // APIC on chip
      }
#endif
      return;
    }
  }

  // unknown CPUID function
  RAX = 0;
  RBX = 0;
  RCX = 0;
  RDX = 0;
#else
  BX_INFO(("CPUID: not available on < 486"));
  exception(BX_UD_EXCEPTION, 0, 0);
#endif
}

void BX_CPU_C::set_cpuid_defaults(void)
{
  Bit8u *vendor_string = (Bit8u *)SIM->get_param_string(BXPN_VENDOR_STRING)->getptr();
  Bit8u *brand_string = (Bit8u *)SIM->get_param_string(BXPN_BRAND_STRING)->getptr();
  bool cpuid_limit_winnt = SIM->get_param_bool(BXPN_CPUID_LIMIT_WINNT)->get();

  cpuid_function_t *cpuid;
  int i;

  for (i=0;i<MAX_STD_CPUID_FUNCTION;i++) {
    BX_CPU_THIS_PTR cpuid_std_function[i].eax = 0;
    BX_CPU_THIS_PTR cpuid_std_function[i].ebx = 0;
    BX_CPU_THIS_PTR cpuid_std_function[i].ecx = 0;
    BX_CPU_THIS_PTR cpuid_std_function[i].edx = 0;
  }

  for (i=0;i<MAX_EXT_CPUID_FUNCTION;i++) {
    BX_CPU_THIS_PTR cpuid_ext_function[i].eax = 0;
    BX_CPU_THIS_PTR cpuid_ext_function[i].ebx = 0;
    BX_CPU_THIS_PTR cpuid_ext_function[i].ecx = 0;
    BX_CPU_THIS_PTR cpuid_ext_function[i].edx = 0;
  }

  // ------------------------------------------------------
  // CPUID function 0x00000000
  cpuid = &(BX_CPU_THIS_PTR cpuid_std_function[0]);

  // EAX: highest input value understood by CPUID
  // EBX: vendor ID string
  // EDX: vendor ID string
  // ECX: vendor ID string

#if BX_CPU_LEVEL <= 5
  // 486 and Pentium processors
  cpuid->eax = 1;
#else
  // for Pentium Pro, Pentium II, Pentium 4 processors
  cpuid->eax = 2;
  // do not report CPUID functions above 0x3 if cpuid_limit_winnt is set
  // to workaround WinNT issue.
  if (! cpuid_limit_winnt) {
    if (BX_SUPPORT_MONITOR_MWAIT)
      cpuid->eax = 0x5;
    if (BX_SUPPORT_XSAVE)
      cpuid->eax = 0xD;
  }
#endif

  // CPUID vendor string (e.g. GenuineIntel, AuthenticAMD, CentaurHauls, ...)
  memcpy(&(cpuid->ebx), vendor_string    , 4);
  memcpy(&(cpuid->edx), vendor_string + 4, 4);
  memcpy(&(cpuid->ecx), vendor_string + 8, 4);

  // ------------------------------------------------------
  // CPUID function 0x00000001
  cpuid = &(BX_CPU_THIS_PTR cpuid_std_function[1]);

  // EAX:       CPU Version Information
  //   [3:0]   Stepping ID
  //   [7:4]   Model: starts at 1
  //   [11:8]  Family: 4=486, 5=Pentium, 6=PPro, ...
  //   [13:12] Type: 0=OEM, 1=overdrive, 2=dual cpu, 3=reserved
  //   [31:14] Reserved
  cpuid->eax = get_cpu_version_information();

  // EBX:
  //   [7:0]   Brand ID
  //   [15:8]  CLFLUSH cache line size (value*8 = cache line size in bytes)
  //   [23:16] Number of logical processors in one physical processor
  //   [31:24] Local Apic ID

  cpuid->ebx = 0;
#if BX_SUPPORT_APIC
  cpuid->ebx |= ((BX_CPU_THIS_PTR lapic.get_id() & 0xff) << 24);
#endif
  if (BX_CPU_SUPPORT_FEATURE(BX_CPU_CLFLUSH)) {
    cpuid->ebx |= (CACHE_LINE_SIZE / 8) << 8;
  }
#if BX_SUPPORT_SMP
  unsigned n_logical_processors = SIM->get_param_num(BXPN_CPU_NCORES)->get()*SIM->get_param_num(BXPN_CPU_NTHREADS)->get();
  if (n_logical_processors > 1)
    cpuid->ebx |= (n_logical_processors << 16);
#endif

  // ECX:       Extended Feature Flags
  //   [0:0]   SSE3: SSE3 Instructions
  //   [1:1]   PCLMULQDQ Instruction support
  //   [2:2]   reserved
  //   [3:3]   MONITOR/MWAIT support
  //   [4:4]   DS-CPL: CPL qualified debug store
  //   [5:5]   VMX: Virtual Machine Technology
  //   [6:6]   SMX: Secure Virtual Machine Technology
  //   [7:7]   EST: Enhanced Intel SpeedStep Technology
  //   [8:8]   TM2: Thermal Monitor 2
  //   [9:9]   SSE3E: SSE3E Instructions (Intel Core Duo 2 new instructions)
  //   [10:10] CNXT-ID: L1 context ID
  //   [11:11] reserved
  //   [12:12] FMA Instructions support
  //   [13:13] CMPXCHG16B: CMPXCHG16B instruction support
  //   [14:14] xTPR update control
  //   [17:15] reserved
  //   [18:18] DCA - Direct Cache Access
  //   [19:19] SSE4.1 Instructions
  //   [20:20] SSE4.2 Instructions
  //   [21:21] X2APIC
  //   [22:22] MOVBE instruction
  //   [23:23] POPCNT instruction
  //   [24:24] reserved
  //   [25:25] AES Instructions
  //   [26:26] XSAVE extensions support
  //   [27:27] OSXSAVE support
  //   [28:28] AVX extensions support
  //   [31:29] reserved
  cpuid->ecx = get_extended_cpuid_features();

  // EDX:       Feature Flags
  //   [0:0]   FPU on chip
  //   [1:1]   VME: Virtual-8086 Mode enhancements
  //   [2:2]   DE: Debug Extensions (I/O breakpoints)
  //   [3:3]   PSE: Page Size Extensions
  //   [4:4]   TSC: Time Stamp Counter
  //   [5:5]   MSR: RDMSR and WRMSR support
  //   [6:6]   PAE: Physical Address Extensions
  //   [7:7]   MCE: Machine Check Exception
  //   [8:8]   CXS: CMPXCHG8B instruction
  //   [9:9]   APIC: APIC on Chip
  //   [10:10] Reserved
  //   [11:11] SYSENTER/SYSEXIT support
  //   [12:12] MTRR: Memory Type Range Reg
  //   [13:13] PGE/PTE Global Bit
  //   [14:14] MCA: Machine Check Architecture
  //   [15:15] CMOV: Cond Mov/Cmp Instructions
  //   [16:16] PAT: Page Attribute Table
  //   [17:17] PSE-36: Physical Address Extensions
  //   [18:18] Processor Serial Number
  //   [19:19] CLFLUSH: CLFLUSH Instruction support
  //   [20:20] Reserved
  //   [21:21] DS: Debug Store
  //   [22:22] ACPI: Thermal Monitor and Software Controlled Clock Facilities
  //   [23:23] MMX Technology
  //   [24:24] FXSR: FXSAVE/FXRSTOR (also indicates CR4.OSFXSR is available)
  //   [25:25] SSE: SSE Extensions
  //   [26:26] SSE2: SSE2 Extensions
  //   [27:27] Reserved
  //   [28:28] Hyper Threading Technology
  //   [29:29] TM: Thermal Monitor
  //   [30:30] Reserved
  //   [31:31] PBE: Pending Break Enable
  cpuid->edx = get_std_cpuid_features();

#if BX_CPU_LEVEL >= 6
  // ------------------------------------------------------
  // CPUID function 0x00000002 - Cache and TLB Descriptors
  cpuid = &(BX_CPU_THIS_PTR cpuid_std_function[2]);

#if BX_CPU_VENDOR_INTEL
  cpuid->eax = 0x00410601;  // for Pentium Pro compatibility
  cpuid->ebx = 0;
  cpuid->ecx = 0;
  cpuid->edx = 0;
#else
  cpuid->eax = 0;           // ignore for AMD
  cpuid->ebx = 0;
  cpuid->ecx = 0;
  cpuid->edx = 0;
#endif

  // ------------------------------------------------------
  // CPUID function 0x00000003 - Processor Serial Number
  cpuid = &(BX_CPU_THIS_PTR cpuid_std_function[3]);

  cpuid->eax = 0;
  cpuid->ebx = 0;
  cpuid->ecx = 0;
  cpuid->edx = 0;

  // do not report CPUID functions above 0x3 if cpuid_limit_winnt is set
  // to workaround WinNT issue.
  if (cpuid_limit_winnt) return;

  // ------------------------------------------------------
  // CPUID function 0x00000004 - Deterministic Cache Parameters
  cpuid = &(BX_CPU_THIS_PTR cpuid_std_function[4]);

  cpuid->eax = 0;
  cpuid->ebx = 0;
  cpuid->ecx = 0;
  cpuid->edx = 0;

#if BX_SUPPORT_MONITOR_MWAIT
  // ------------------------------------------------------
  // CPUID function 0x00000005
  cpuid = &(BX_CPU_THIS_PTR cpuid_std_function[5]);

  // EAX - Smallest monitor-line size in bytes
  // EBX - Largest  monitor-line size in bytes
  // ECX -
  //   [31:2] - reserved
  //    [1:1] - exit MWAIT even with EFLAGS.IF = 0
  //    [0:0] - MONITOR/MWAIT extensions are supported
  // EDX - Reserved
  cpuid->eax = CACHE_LINE_SIZE;
  cpuid->ebx = CACHE_LINE_SIZE;
  cpuid->ecx = 3;
  cpuid->edx = 0;
#endif

#if BX_SUPPORT_XSAVE
  // ------------------------------------------------------
  // CPUID function 0x0000000D
  cpuid = &(BX_CPU_THIS_PTR cpuid_std_function[0xD]);

  // EAX - XCR0 lower 32 bits
  // EBX - Maximum size (in bytes) required by enabled features
  // ECX - Maximum size (in bytes) required by CPU supported features
  // EDX - XCR0 upper 32 bits
  cpuid->eax = BX_CPU_THIS_PTR xcr0.get32();
  cpuid->ebx = 512+64;
  cpuid->ecx = 512+64;
  cpuid->edx = 0;
#endif

  // do not report Pentium 4 extended functions if not needed
  if ((BX_CPU_THIS_PTR cpuid_features_bitmask & BX_CPU_SSE2) == 0)
    return;

  // ------------------------------------------------------
  // CPUID function 0x80000000
  cpuid = &(BX_CPU_THIS_PTR cpuid_ext_function[0]);

  // EAX: highest input value understood by CPUID
  // EBX: vendor ID string
  // EDX: vendor ID string
  // ECX: vendor ID string
  cpuid->eax = BX_SUPPORT_X86_64 ? 0x80000008 : 0x80000004;
#if BX_CPU_VENDOR_INTEL
  cpuid->ebx = 0;
  cpuid->edx = 0;          // Reserved for Intel
  cpuid->ecx = 0;
#else
  memcpy(&(cpuid->ebx), vendor_string    , 4);
  memcpy(&(cpuid->edx), vendor_string + 4, 4);
  memcpy(&(cpuid->ecx), vendor_string + 8, 4);
#endif

  // ------------------------------------------------------
  // CPUID function 0x80000001
  cpuid = &(BX_CPU_THIS_PTR cpuid_ext_function[1]);

  // EAX:       CPU Version Information
  cpuid->eax = BX_CPU_VENDOR_INTEL ? 0 : get_cpu_version_information();

  // EBX:       Brand ID
  cpuid->ebx = 0;

  // ECX:
  //     [0:0]   LAHF/SAHF available in 64-bit mode
  //     [1:1]   AMD CmpLegacy
  //     [2:2]   AMD Secure Virtual Machine Technology
  //     [3:3]   Extended APIC Space
  //     [4:4]   Alternative CR8 (treat lock mov cr0 as mov cr8)
  //     [5:5]   LZCNT support
  //     [6:6]   SSE4A support
  //     [7:7]   Misaligned SSE support
  //     [8:8]   3DNow! prefetch support
  //     [9:9]   OS visible workarounds
  //     [10:10] Reserved
  //     [11:11] SSE5A
  //     [12:31] Reserved
#if BX_SUPPORT_X86_64
  cpuid->ecx = 1 | (1<<8);
#endif
#if BX_SUPPORT_MISALIGNED_SSE
  cpuid->ecx |= (1<<7);
#endif

  // EDX:
  // Many of the bits in EDX are the same as EAX [*] for AMD
  // [*] [0:0]   FPU on chip
  // [*] [1:1]   VME: Virtual-8086 Mode enhancements
  // [*] [2:2]   DE: Debug Extensions (I/O breakpoints)
  // [*] [3:3]   PSE: Page Size Extensions
  // [*] [4:4]   TSC: Time Stamp Counter
  // [*] [5:5]   MSR: RDMSR and WRMSR support
  // [*] [6:6]   PAE: Physical Address Extensions
  // [*] [7:7]   MCE: Machine Check Exception
  // [*] [8:8]   CXS: CMPXCHG8B instruction
  // [*] [9:9]   APIC: APIC on Chip
  //     [10:10] Reserved
  //     [11:11] SYSCALL/SYSRET support
  // [*] [12:12] MTRR: Memory Type Range Reg
  // [*] [13:13] PGE/PTE Global Bit
  // [*] [14:14] MCA: Machine Check Architecture
  // [*] [15:15] CMOV: Cond Mov/Cmp Instructions
  // [*] [16:16] PAT: Page Attribute Table
  // [*] [17:17] PSE-36: Physical Address Extensions
  //     [18:19] Reserved
  //     [20:20] No-Execute page protection
  //     [21:21] Reserved
  //     [22:22] AMD MMX Extensions
  // [*] [23:23] MMX Technology
  // [*] [24:24] FXSR: FXSAVE/FXRSTOR (also indicates CR4.OSFXSR is available)
  //     [25:25] Fast FXSAVE/FXRSTOR mode support
  //     [26:26] 1G paging support
  //     [27:27] Support RDTSCP Instruction
  //     [28:28] Reserved
  //     [29:29] Long Mode
  //     [30:30] AMD 3DNow! Extensions
  //     [31:31] AMD 3DNow! Instructions
  unsigned features  = BX_CPU_VENDOR_INTEL ? 0 : get_std_cpuid_features();
  features &= 0x0183F3FF;
#if BX_SUPPORT_3DNOW
  features |= (1 << 22) | (1 << 30) | (1 << 31);  // only AMD is interesting in AMD MMX extensions
#endif
#if BX_SUPPORT_X86_64
  features |= (1 << 29) | (1 << 27) | (1 << 25) | (1 << 20) | (1 << 11);
#if BX_SUPPORT_1G_PAGES
  features |= (1 << 26);
#endif
#endif
  cpuid->edx = features;

  // Processor Brand String, use the value that is returned
  // by the first processor in the Pentium 4 family
  // (according to Intel manual or the AMD manual)

  // ------------------------------------------------------
  // CPUID function 0x80000002

  cpuid = &(BX_CPU_THIS_PTR cpuid_ext_function[2]);
  memcpy(&(cpuid->eax), brand_string     , 4);
  memcpy(&(cpuid->ebx), brand_string +  4, 4);
  memcpy(&(cpuid->ecx), brand_string +  8, 4);
  memcpy(&(cpuid->edx), brand_string + 12, 4);

  // CPUID function 0x80000003
  cpuid = &(BX_CPU_THIS_PTR cpuid_ext_function[3]);
  memcpy(&(cpuid->eax), brand_string + 16, 4);
  memcpy(&(cpuid->ebx), brand_string + 20, 4);
  memcpy(&(cpuid->ecx), brand_string + 24, 4);
  memcpy(&(cpuid->edx), brand_string + 28, 4);

  // CPUID function 0x80000004
  cpuid = &(BX_CPU_THIS_PTR cpuid_ext_function[4]);
  memcpy(&(cpuid->eax), brand_string + 32, 4);
  memcpy(&(cpuid->ebx), brand_string + 36, 4);
  memcpy(&(cpuid->ecx), brand_string + 40, 4);
  memcpy(&(cpuid->edx), brand_string + 44, 4);

#if BX_SUPPORT_X86_64
  // ------------------------------------------------------
  // CPUID function 0x80000005

#if BX_CPU_VENDOR_INTEL == 0
  cpuid = &(BX_CPU_THIS_PTR cpuid_ext_function[5]);

  /* cache info (L1 cache) */
  cpuid->eax = 0x01ff01ff;
  cpuid->ebx = 0x01ff01ff;
  cpuid->ecx = 0x40020140;
  cpuid->edx = 0x40020140;
#endif

  // ------------------------------------------------------
  // CPUID function 0x80000006
  cpuid = &(BX_CPU_THIS_PTR cpuid_ext_function[6]);

  /* cache info (L2 cache) */
  cpuid->eax = 0;
  cpuid->ebx = 0x42004200;
  cpuid->ecx = 0x02008140;
  cpuid->edx = 0;

  // ------------------------------------------------------
  // CPUID function 0x00000007
  cpuid = &(BX_CPU_THIS_PTR cpuid_ext_function[7]);

  cpuid->eax = 0;
  cpuid->ebx = 0;
  cpuid->ecx = 0;
  cpuid->edx = 0;

  // ------------------------------------------------------
  // CPUID function 0x80000008
  cpuid = &(BX_CPU_THIS_PTR cpuid_ext_function[8]);

  // virtual & phys address size in low 2 bytes.
  cpuid->eax = BX_PHY_ADDRESS_WIDTH | (BX_LIN_ADDRESS_WIDTH << 8);
  cpuid->ebx = 0;
  cpuid->ecx = 0; // Reserved, undefined
  cpuid->edx = 0;

#endif // BX_SUPPORT_X86_64

#endif // BX_CPU_LEVEL >= 6
}

void BX_CPU_C::init_cpu_features_bitmask(void)
{
  Bit32u features_bitmask = 0;

  bx_bool aes_enabled = SIM->get_param_bool(BXPN_CPUID_AES)->get();
  bx_bool movbe_enabled = SIM->get_param_bool(BXPN_CPUID_MOVBE)->get();
  unsigned sse_enabled = SIM->get_param_enum(BXPN_CPUID_SSE)->get();

  // sanity checks
  if (aes_enabled) {
     // AES required 3-byte opcode (SSS3E support or more)
     if (sse_enabled < BX_CPUID_SUPPORT_SSSE3) {
       BX_PANIC(("PANIC: AES support requires SSSE3 or higher !"));
       return;
     }
  }

  if (movbe_enabled) {
     // MOVBE required 3-byte opcode (SSS3E support or more)
     if (sse_enabled < BX_CPUID_SUPPORT_SSSE3) {
       BX_PANIC(("PANIC: MOVBE support requires SSSE3 or higher !"));
       return;
     }
  }

  if (sse_enabled) {
     if (BX_SUPPORT_MMX == 0 || BX_CPU_LEVEL < 6) {
       BX_PANIC(("PANIC: SSE support requires P6 emulation with MMX enabled !"));
       return;
     }
  }
  else {
     if (BX_SUPPORT_XSAVE) {
       BX_PANIC(("PANIC: XSAVE emulation requires SSE support !"));
       return;
     }
  }

#if BX_SUPPORT_X86_64
  if (sse_enabled <= BX_CPUID_SUPPORT_SSE2) {
    BX_PANIC(("PANIC: x86-64 emulation requires SSE2 support !"));
    return;
  }
#endif

#if BX_SUPPORT_FPU
  features_bitmask |= BX_CPU_X87;
#endif
#if BX_CPU_LEVEL >= 4
  features_bitmask |= BX_CPU_486;
#endif
#if BX_CPU_LEVEL >= 5
  features_bitmask |= BX_CPU_PENTIUM;
#endif
#if BX_CPU_LEVEL >= 6
  features_bitmask |= BX_CPU_P6;
#endif
#if BX_SUPPORT_MMX
  features_bitmask |= BX_CPU_MMX;
#endif
#if BX_SUPPORT_3DNOW
  features_bitmask |= BX_CPU_3DNOW;
#endif
#if BX_SUPPORT_MONITOR_MWAIT
  features_bitmask |= BX_CPU_MONITOR_MWAIT;
#endif

#if BX_CPU_LEVEL >= 6
  // enabled CLFLUSH only when SSE2 or higher is enabled
  if (sse_enabled >= BX_CPUID_SUPPORT_SSE2)
    features_bitmask |= BX_CPU_CLFLUSH;

  // determine SSE in runtime
  switch (sse_enabled) {
    case BX_CPUID_SUPPORT_SSE4_2:
      features_bitmask |= BX_CPU_SSE4_2;
    case BX_CPUID_SUPPORT_SSE4_1:
      features_bitmask |= BX_CPU_SSE4_1;
    case BX_CPUID_SUPPORT_SSSE3:
      features_bitmask |= BX_CPU_SSSE3;
    case BX_CPUID_SUPPORT_SSE3:
      features_bitmask |= BX_CPU_SSE3;
    case BX_CPUID_SUPPORT_SSE2:
      features_bitmask |= BX_CPU_SSE2;
    case BX_CPUID_SUPPORT_SSE:
      features_bitmask |= BX_CPU_SSE;
    case BX_CPUID_SUPPORT_NOSSE:
    default:
      break;
  };
#endif

#if BX_SUPPORT_SEP
  features_bitmask |= BX_CPU_SYSENTER_SYSEXIT;
#endif
#if BX_SUPPORT_VMX
  features_bitmask |= BX_CPU_VMX;
#endif
#if BX_SUPPORT_XSAVE
  features_bitmask |= BX_CPU_XSAVE;
#endif

#if BX_CPU_LEVEL >= 6
  if (aes_enabled) {
    features_bitmask |= BX_CPU_AES;
    features_bitmask |= BX_CPU_PCLMULQDQ;
  }

  if (movbe_enabled)
    features_bitmask |= BX_CPU_MOVBE;
#endif

#if BX_SUPPORT_X86_64
  features_bitmask |= BX_CPU_X86_64;
#endif

  BX_CPU_THIS_PTR cpuid_features_bitmask = features_bitmask;
}