Question

我试图用g95编译一个fortran程序，但是编译过程中出现了一个错误：“未定义对mvbits的引用”。我从网上下载了g95。匿名-a： 4.9.0-8-amd64＃1 SMP Debian 4.9.130-2（2018-10-27）x86_64 GNU / Linux

g95 -c -03 -g -I . mkieee.f
g95 -o mk mkieee.o
mkieee.o: In function`mkieee_':
mkieee.f:82: undefined reference to `mvbits_'
mkieee.f:97: undefined reference to `mvbits_'
g95-install/bin/../lib/gcc-lib/x86_64-inknown-linux-gnu/4.0.3/libf95.a(main.o): In function `main':
(.text+0xa): undefined reference to `MAIN_'

我知道，mvbits是g95中的固有子程序，但是出了什么问题？

更新mkieee.f：

  subroutine mkieee(a,rieee,num)  

  real(4),intent(in) :: a(num)
  real(4),intent(out) :: rieee(num)
  integer,intent(in) :: num

  integer(4) :: ieee 

  real, parameter :: two23=scale(1.0,23)
  real, parameter :: two126=scale(1.0,126)

  alog2=alog(2.0)

  do j=1,num
    ieee=0

    if (a(j).eq.0.) then
      ieee=0
      rieee(j)=transfer(ieee,rieee(j))
!       write(6,fmt='(f20.10,5x,b32)') a,a
!       write(6,fmt='(f20.10,5x,b32)') rieee,rieee
      cycle
    endif

!
!  Set Sign bit (bit 31 - leftmost bit)
!
    if (a(j).lt.0.0) then
      ieee=ibset(ieee,31)
      atemp=abs(a(j))
    else
      ieee=ibclr(ieee,31)
      atemp=a(j)
    endif
!
!  Determine exponent n with base 2
!
    if ( atemp .ge. 1.0 ) then
       n = 0
       do while ( 2.0**(n+1) .le. atemp )
          n = n + 1
       enddo
    else
       n = -1
       do while ( 2.0**n .gt. atemp )
          n = n - 1
       enddo
    endif
!        n=floor(alog(atemp)/alog2)
    !write(6,*) ' logstuff ',alog(atemp)/alog2
    !write(6,*) ' logstuffn ',n
    iexp=n+127
    if (n.gt.127) iexp=255     ! overflow
    if (n.lt.-127) iexp=0
    !      set exponent bits ( bits 30-23 )
    call mvbits(iexp,0,8,ieee,23)
!
!  Determine Mantissa
! 
    if (iexp.ne.255) then
      if (iexp.ne.0) then
        atemp=(atemp/(2.0**n))-1.0
      else
        atemp=atemp*two126
      endif
      imant=nint(atemp*two23)
    else
      imant=0
    endif
    !      set mantissa bits ( bits 22-0 )
    call mvbits(imant,0,23,ieee,0)
!
!  Transfer IEEE bit string to real variable
!
    rieee(j)=transfer(ieee,rieee(j))
!       write(6,fmt='(f20.10,5x,b32)') a,a
!       write(6,fmt='(f20.10,5x,b32)') rieee,rieee

  enddo

  return
  end

g95错误：对mvbit的未定义引用

0 个答案: