Macros starting with 'i' in i386/isa

• INTRDIS i386/isa/icu.h:62
• INTREN i386/isa/icu.h:61
• INTRMASK i386/isa/icu.h:63
• IRQ_BIT i386/isa/vector.s:12
• IRQ_BYTE i386/isa/vector.s:13
• isdigit i386/isa/spkr.c:135