AC_BUS_ERROR       21 arch/m68k/include/asm/contregs.h #define AC_BUS_ERROR  0x60000000    /* 34  Not cleared on read, byte.        */
AC_BUS_ERROR       35 arch/m68k/include/asm/sun3mmu.h #define AC_BUS_ERROR  0x60000000    /* 34  Cleared on read, byte.            */