cpuinfo.c

/* small utility to extract CPU information
   Used by configure to set CPU optimization levels on some operating
   systems where /proc/cpuinfo is non-existent or unreliable. */

#include <stdio.h>
#include <sys/time.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#if defined(__MINGW32__) && (__MINGW32_MAJOR_VERSION <= 3) && (__MINGW32_MINOR_VERSION < 10)
#include <sys/timeb.h>
void gettimeofday(struct timeval* t,void* timezone) {
  struct timeb timebuffer;
  ftime( &timebuffer );
  t->tv_sec=timebuffer.time;
  t->tv_usec=1000*timebuffer.millitm;
}
#endif
#ifdef __MINGW32__
#define MISSING_USLEEP
#include <windows.h>
#define sleep(t) Sleep(1000*t);
#endif

#ifdef __BEOS__
#define usleep(t) snooze(t)
#endif

#ifdef M_UNIX
typedef long long int64_t;
#define MISSING_USLEEP
#else
#include <inttypes.h>
#endif

#define CPUID_FEATURE_DEF(bit, desc, description) \
  { bit, desc }

typedef struct cpuid_regs {
  unsigned int eax;
  unsigned int ebx;
  unsigned int ecx;
  unsigned int edx;
} cpuid_regs_t;

static cpuid_regs_t
cpuid(int func) {
  cpuid_regs_t regs;
#define CPUID   ".byte 0x0f, 0xa2; "
#ifdef __x86_64__
  asm("mov %%rbx, %%rsi\n\t"
#else
  asm("mov %%ebx, %%esi\n\t"
#endif
      CPUID"\n\t"
#ifdef __x86_64__
      "xchg %%rsi, %%rbx\n\t"
#else
      "xchg %%esi, %%ebx\n\t"
#endif
      : "=a" (regs.eax), "=S" (regs.ebx), "=c" (regs.ecx), "=d" (regs.edx)
      : "0" (func));
  return regs;
}


static int64_t
rdtsc(void)
{
  uint64_t i;
#define RDTSC   ".byte 0x0f, 0x31; "
  asm volatile (RDTSC : "=A"(i) : );
  return i;
}

static const char*
brandname(int i)
{
  const static char* brandmap[] = {
    NULL,
    "Intel(R) Celeron(R) processor",
    "Intel(R) Pentium(R) III processor",
    "Intel(R) Pentium(R) III Xeon(tm) processor",
    "Intel(R) Pentium(R) III processor",
    NULL,
    "Mobile Intel(R) Pentium(R) III processor-M",
    "Mobile Intel(R) Celeron(R) processor"
  };

  if (i >= sizeof(brandmap))
    return NULL;
  else
    return brandmap[i];
}

static void
store32(char *d, unsigned int v)
{
  d[0] =  v        & 0xff;
  d[1] = (v >>  8) & 0xff;
  d[2] = (v >> 16) & 0xff;
  d[3] = (v >> 24) & 0xff;
}


int
main(int argc, char **argv)
{
  cpuid_regs_t regs, regs_ext;
  char idstr[13];
  unsigned max_cpuid;
  unsigned max_ext_cpuid;
  unsigned int amd_flags;
  unsigned int amd_flags2;
  const char *model_name = NULL;
  int i;
  char processor_name[49];

  regs = cpuid(0);
  max_cpuid = regs.eax;
  /* printf("%d CPUID function codes\n", max_cpuid+1); */

  store32(idstr+0, regs.ebx);
  store32(idstr+4, regs.edx);
  store32(idstr+8, regs.ecx);
  idstr[12] = 0;
  printf("vendor_id\t: %s\n", idstr);

  regs_ext = cpuid((1<<31) + 0);
  max_ext_cpuid = regs_ext.eax;
  if (max_ext_cpuid >= (1<<31) + 1) {
    regs_ext = cpuid((1<<31) + 1);
    amd_flags = regs_ext.edx;
    amd_flags2 = regs_ext.ecx;

    if (max_ext_cpuid >= (1<<31) + 4) {
      for (i = 2; i <= 4; i++) {
        regs_ext = cpuid((1<<31) + i);
        store32(processor_name + (i-2)*16, regs_ext.eax);
        store32(processor_name + (i-2)*16 + 4, regs_ext.ebx);
        store32(processor_name + (i-2)*16 + 8, regs_ext.ecx);
        store32(processor_name + (i-2)*16 + 12, regs_ext.edx);
      }
      processor_name[48] = 0;
      model_name = processor_name;
      while (*model_name == ' ') {
        model_name++;
      }
    }
  } else {
    amd_flags = 0;
    amd_flags2 = 0;
  }

  if (max_cpuid >= 1) {
    static struct {
      int bit;
      char *desc;
    } cap[] = {
      CPUID_FEATURE_DEF(0, "fpu", "Floating-point unit on-chip"),
      CPUID_FEATURE_DEF(1, "vme", "Virtual Mode Enhancements"),
      CPUID_FEATURE_DEF(2, "de", "Debugging Extension"),
      CPUID_FEATURE_DEF(3, "pse", "Page Size Extension"),
      CPUID_FEATURE_DEF(4, "tsc", "Time Stamp Counter"),
      CPUID_FEATURE_DEF(5, "msr", "Pentium Processor MSR"),
      CPUID_FEATURE_DEF(6, "pae", "Physical Address Extension"),
      CPUID_FEATURE_DEF(7, "mce", "Machine Check Exception"),
      CPUID_FEATURE_DEF(8, "cx8", "CMPXCHG8B Instruction Supported"),
      CPUID_FEATURE_DEF(9, "apic", "On-chip APIC Hardware Enabled"),
      CPUID_FEATURE_DEF(11, "sep", "SYSENTER and SYSEXIT"),
      CPUID_FEATURE_DEF(12, "mtrr", "Memory Type Range Registers"),
      CPUID_FEATURE_DEF(13, "pge", "PTE Global Bit"),
      CPUID_FEATURE_DEF(14, "mca", "Machine Check Architecture"),
      CPUID_FEATURE_DEF(15, "cmov", "Conditional Move/Compare Instruction"),
      CPUID_FEATURE_DEF(16, "pat", "Page Attribute Table"),
      CPUID_FEATURE_DEF(17, "pse36", "Page Size Extension 36-bit"),
      CPUID_FEATURE_DEF(18, "pn", "Processor Serial Number"),
      CPUID_FEATURE_DEF(19, "clflush", "CFLUSH instruction"),
      CPUID_FEATURE_DEF(21, "dts", "Debug Store"),
      CPUID_FEATURE_DEF(22, "acpi", "Thermal Monitor and Clock Ctrl"),
      CPUID_FEATURE_DEF(23, "mmx", "MMX Technology"),
      CPUID_FEATURE_DEF(24, "fxsr", "FXSAVE/FXRSTOR"),
      CPUID_FEATURE_DEF(25, "sse", "SSE Extensions"),
      CPUID_FEATURE_DEF(26, "sse2", "SSE2 Extensions"),
      CPUID_FEATURE_DEF(27, "ss", "Self Snoop"),
      CPUID_FEATURE_DEF(28, "ht", "Multi-threading"),
      CPUID_FEATURE_DEF(29, "tm", "Therm. Monitor"),
      CPUID_FEATURE_DEF(30, "ia64", "IA-64 Processor"),
      CPUID_FEATURE_DEF(31, "pbe", "Pend. Brk. EN."),
      { -1 }
    };
    static struct {
      int bit;
      char *desc;
    } cap2[] = {
      CPUID_FEATURE_DEF(0, "pni", "SSE3 Extensions"),
      CPUID_FEATURE_DEF(3, "monitor", "MONITOR/MWAIT"),
      CPUID_FEATURE_DEF(4, "ds_cpl", "CPL Qualified Debug Store"),
      CPUID_FEATURE_DEF(5, "vmx", "Virtual Machine Extensions"),
      CPUID_FEATURE_DEF(6, "smx", "Safer Mode Extensions"),
      CPUID_FEATURE_DEF(7, "est", "Enhanced Intel SpeedStep Technology"),
      CPUID_FEATURE_DEF(8, "tm2", "Thermal Monitor 2"),
      CPUID_FEATURE_DEF(9, "ssse3", "Supplemental SSE3"),
      CPUID_FEATURE_DEF(10, "cid", "L1 Context ID"),
      CPUID_FEATURE_DEF(13, "cx16", "CMPXCHG16B Available"),
      CPUID_FEATURE_DEF(14, "xtpr", "xTPR Disable"),
      CPUID_FEATURE_DEF(15, "pdcm", "Perf/Debug Capability MSR"),
      CPUID_FEATURE_DEF(18, "dca", "Direct Cache Access"),
      CPUID_FEATURE_DEF(19, "sse41", "SSE4.1 Extensions"),
      CPUID_FEATURE_DEF(20, "sse42", "SSE4.2 Extensions"),
      CPUID_FEATURE_DEF(23, "popcnt", "Pop Count Instruction"),
      { -1 }
    };
    static struct {
      int bit;
      char *desc;
    } cap_amd[] = {
      CPUID_FEATURE_DEF(11, "syscall", "SYSCALL and SYSRET"),
      CPUID_FEATURE_DEF(19, "mp", "MP Capable"),
      CPUID_FEATURE_DEF(20, "nx", "No-Execute Page Protection"),
      CPUID_FEATURE_DEF(22, "mmxext", "MMX Technology (AMD Extensions)"),
      CPUID_FEATURE_DEF(25, "fxsr_opt", "Fast FXSAVE/FXRSTOR"),
      CPUID_FEATURE_DEF(26, "pdpe1gb", "PDP Entry for 1GiB Page"),
      CPUID_FEATURE_DEF(27, "rdtscp", "RDTSCP Instruction"),
      CPUID_FEATURE_DEF(29, "lm", "Long Mode Capable"),
      CPUID_FEATURE_DEF(30, "3dnowext", "3DNow! Extensions"),
      CPUID_FEATURE_DEF(31, "3dnow", "3DNow!"),
      { -1 }
    };
    static struct {
      int bit;
      char *desc;
    } cap_amd2[] = {
      CPUID_FEATURE_DEF(0, "lahf_lm", "LAHF/SAHF Supported in 64-bit Mode"),
      CPUID_FEATURE_DEF(1, "cmp_legacy", "Chip Multi-Core"),
      CPUID_FEATURE_DEF(2, "svm", "Secure Virtual Machine"),
      CPUID_FEATURE_DEF(3, "extapic", "Extended APIC Space"),
      CPUID_FEATURE_DEF(4, "cr8legacy", "CR8 Available in Legacy Mode"),
      CPUID_FEATURE_DEF(5, "abm", "Advanced Bit Manipulation"),
      CPUID_FEATURE_DEF(6, "sse4a", "SSE4A Extensions"),
      CPUID_FEATURE_DEF(7, "misalignsse", "Misaligned SSE Mode"),
      CPUID_FEATURE_DEF(8, "3dnowprefetch", "3DNow! Prefetch/PrefetchW"),
      CPUID_FEATURE_DEF(9, "osvw", "OS Visible Workaround"),
      CPUID_FEATURE_DEF(10, "ibs", "Instruction Based Sampling"),
      { -1 }
    };
    unsigned int family, model, stepping;

    regs = cpuid(1);
    family = (regs.eax >> 8) & 0xf;
    model = (regs.eax >> 4) & 0xf;
    stepping = regs.eax & 0xf;

    if (family == 0xf)
      family += (regs.eax >> 20) & 0xff;
    if (family == 0xf || family == 6)
      model += ((regs.eax >> 16) & 0xf) << 4;

    printf("cpu family\t: %d\n"
           "model\t\t: %d\n"
           "stepping\t: %d\n" ,
           family,
           model,
           stepping);

    if (strstr(idstr, "Intel") && !model_name) {
      if (family == 6 && model == 0xb && stepping == 1)
        model_name = "Intel (R) Celeron (R) processor";
      else
        model_name = brandname(regs.ebx & 0xf);
    }

    printf("flags\t\t:");
    for (i = 0; cap[i].bit >= 0; i++) {
      if (regs.edx & (1 << cap[i].bit)) {
        printf(" %s", cap[i].desc);
      }
    }
    for (i = 0; cap2[i].bit >= 0; i++) {
      if (regs.ecx & (1 << cap2[i].bit)) {
        printf(" %s", cap2[i].desc);
      }
    }
    /* k6_mtrr is supported by some AMD K6-2/K6-III CPUs but
       it is not indicated by a CPUID feature bit, so we
       have to check the family, model and stepping instead. */
    if (strstr(idstr, "AMD") &&
        family == 5 &&
        (model >= 9 || model == 8 && stepping >= 8))
      printf(" %s", "k6_mtrr");
    /* similar for cyrix_arr. */
    if (strstr(idstr, "Cyrix") &&
        (family == 5 && model < 4 || family == 6))
      printf(" %s", "cyrix_arr");
    /* as well as centaur_mcr. */
    if (strstr(idstr, "Centaur") &&
        family == 5)
      printf(" %s", "centaur_mcr");

    for (i = 0; cap_amd[i].bit >= 0; i++) {
      if (amd_flags & (1 << cap_amd[i].bit)) {
        printf(" %s", cap_amd[i].desc);
      }
    }
    for (i = 0; cap_amd2[i].bit >= 0; i++) {
      if (amd_flags2 & (1 << cap_amd2[i].bit)) {
        printf(" %s", cap_amd2[i].desc);
      }
    }
    printf("\n");

    if (regs.edx & (1 << 4)) {
      int64_t tsc_start, tsc_end;
      struct timeval tv_start, tv_end;
      int usec_delay;

      tsc_start = rdtsc();
      gettimeofday(&tv_start, NULL);
#ifdef  MISSING_USLEEP
      sleep(1);
#else
      usleep(100000);
#endif
      tsc_end = rdtsc();
      gettimeofday(&tv_end, NULL);

      usec_delay = 1000000 * (tv_end.tv_sec - tv_start.tv_sec)
        + (tv_end.tv_usec - tv_start.tv_usec);

      printf("cpu MHz\t\t: %.3f\n",
             (double)(tsc_end-tsc_start) / usec_delay);
    }
  }

  printf("model name\t: ");
  if (model_name)
    printf("%s\n", model_name);
  else
    printf("Unknown %s CPU\n", idstr);
}