UNIX 6th Ed. - /usr/source/s4/getchr.s

   1: / getchar() -- get a character from input file fin
   2: 
   3: .globl  _getchar
   4: .comm   _errno,2
   5: .comm   _fin,518.
   6: 
   7: _getchar:
   8:         mov     r5,-(sp)
   9:         mov     sp,r5
  10:         dec     _fin+2
  11:         bge     1f
  12:         mov     $_fin+6,_fin+4
  13:         mov     _fin,r0
  14:         sys     read; _fin+6; 512.
  15:         bes     badret
  16:         tst     r0
  17:         beq     badret
  18:         dec     r0
  19:         mov     r0,_fin+2
  20: 1:
  21:         clr     r0
  22:         bisb    *_fin+4,r0
  23:         inc     _fin+4
  24:         mov     (sp)+,r5
  25:         rts     pc
  26: 
  27: badret:
  28:         mov     r0,_errno
  29:         clr     r0
  30:         clr     _fin+2
  31:         mov     (sp)+,r5
  32:         rts     pc

Defined functions

Defined variables