mp.c

#include "types.h"
#include "mp.h"
#include "defs.h"
#include "param.h"
#include "x86.h"
#include "traps.h"
#include "mmu.h"
#include "proc.h"

static char *buses[] = {
  "CBUSI ",
  "CBUSII",
  "EISA  ",
  "FUTURE",
  "INTERN",
  "ISA   ",
  "MBI   ",
  "MBII  ",
  "MCA   ",
  "MPI   ",
  "MPSA  ",
  "NUBUS ",
  "PCI   ",
  "PCMCIA",
  "TC    ",
  "VL    ",
  "VME   ",
  "XPRESS",
  0,
};

struct cpu cpus[NCPU];
int ismp;
int ncpu;
uchar ioapic_id;

static struct cpu *bcpu;
static struct mp *mp;  // The MP floating point structure

static struct mp*
mp_scan(uchar *addr, int len)
{
  uchar *e, *p, sum;
  int i;

  e = addr+len;
  for(p = addr; p < e; p += sizeof(struct mp)){
    if(memcmp(p, "_MP_", 4))
      continue;
    sum = 0;
    for(i = 0; i < sizeof(struct mp); i++)
      sum += p[i];
    if(sum == 0)
      return (struct mp*)p;
  }
  return 0;
}

// Search for the MP Floating Pointer Structure, which according to the
// spec is in one of the following three locations:
// 1) in the first KB of the EBDA;
// 2) in the last KB of system base memory;
// 3) in the BIOS ROM between 0xE0000 and 0xFFFFF.
static struct mp*
mp_search(void)
{
  uchar *bda;
  uint p;
  struct mp *mp;