text: /* The kernel call implemented in this file:
   *   m_type:	SYS_READBIOS
   *
   * The parameters for this kernel call are:
   *	m_lsys_krn_readbios.size	number of bytes to copy
   *	m_lsys_krn_readbios.addr	absolute address in BIOS area
   *	m_lsys_krn_readbios.buf		buffer address in requesting process
   */
  
  #include "kernel/system.h"
  #include <minix/type.h>
  
  /*===========================================================================*
   *				do_readbios				     *
   *===========================================================================*/
  int do_readbios(struct proc * caller, message * m_ptr)
  {
    struct vir_addr src, dst;
    size_t len = m_ptr->m_lsys_krn_readbios.size;
    vir_bytes limit;
  
    src.offset = m_ptr->m_lsys_krn_readbios.addr;
    dst.offset = m_ptr->m_lsys_krn_readbios.buf;
    src.proc_nr_e = NONE;
    dst.proc_nr_e = m_ptr->m_source;      
  
    limit = src.offset + len - 1;
  
  #define VINRANGE(v, a, b) ((a) <= (v) && (v) <= (b))
  #define SUBRANGE(a,b,c,d) (VINRANGE((a), (c), (d)) && VINRANGE((b),(c),(d)))
  #define USERRANGE(a, b) SUBRANGE(src.offset, limit, (a), (b))
  
    if(!USERRANGE(BIOS_MEM_BEGIN, BIOS_MEM_END) &&
       !USERRANGE(BASE_MEM_TOP, UPPER_MEM_END))
    	return EPERM;
  
    return virtual_copy_vmcheck(caller, &src, &dst, m_ptr->m_lsys_krn_readbios.size);
  }
  