Espresso/kernel/boot.c

#include <stdint.h>
#include <string.h>
#include <cpuid.h>
#include <stdlib.h>

#include <kernel/boot.h>


extern uint8_t __bss_start;
extern uint8_t __bss_end;


void clear_bss(void)
{
  /*memset(&__bss_start, 0, &__bss_end - &__bss_start);*/
  
  for (int i = 0; i < ((&__bss_end) - (&__bss_start)); i++)
  {
    (&(__bss_start))[i] = 0x0;
  }
}

char* get_cpu_vendor_string(void)
{
  unsigned int eax, ebx, ecx, edx;
  char vendor[13];

  if (!__get_cpuid(0, &eax, &ebx, &ecx, &edx))
  {
    return strdup("Unknown");
  }

  memcpy(&vendor[0], &ebx, 4);
  memcpy(&vendor[4], &edx, 4);
  memcpy(&vendor[8], &ecx, 4);
  vendor[12] = '\0';

  return strdup(vendor);
}

char* get_cpu_brand_string(void)
{
  unsigned int eax = 0, ebx = 0, ecx = 0, edx = 0;
  
  int k = __get_cpuid_max(0x80000000, NULL);

  if (k >= (int) 0x80000005)
  {
    return strdup("Unknown");
  }

  char brand[49]; 
  unsigned int* brand_ptr = (unsigned int*) brand;

  for (unsigned int i = 0; i < 3; ++i)
  {
    __get_cpuid(0x80000002 + i, &eax, &ebx, &ecx, &edx);
    brand_ptr[i * 4 + 0] = eax;
    brand_ptr[i * 4 + 1] = ebx;
    brand_ptr[i * 4 + 2] = ecx;
    brand_ptr[i * 4 + 3] = edx;
  }

  brand[48] = '\0';
  return strdup(brand);
}