1991/0705/pc/io.h (diff list | history)

pc/io.h on 1991/0703
1991/0703		/*
1991/0704		* 8259 interrupt controllers
1991/0703		*/
1991/0704		enum { Int0ctl= 0x20, /* control port */ Int0aux= 0x21, /* everything else port */ Int1ctl= 0xA0, /* control port */ Int1aux= 0xA1, /* everything else port */ Intena= 0x20, /* written to Intctlport, enables next int */ Int0vec= 17, /* first interrupt vector used by the 8259 */ Clockvec= Int0vec+0, /* clock interrupts */ Kbdvec= Int0vec+1, /* keyboard interrupts */
1991/0703		};
1991/0704		#define INT0ENABLE outb(Int0ctl, Intena) #define INT1ENABLE outb(Int1ctl, Intena)
1991/0703		/*
1991/0704		* 8237 dma controllers */ enum { /* * the byte registers for DMA0 are all one byte apart */ Dma0= 0x00, Dma0status= Dma0+0x8, /* status port */ Dma0reset= Dma0+0xD, /* reset port */ /* * the byte registers for DMA1 are all two bytes apart (why?) */ Dma1= 0xC0, Dma1status= Dma1+2*0x8, /* status port */
1991/0705		Dma1reset= Dma1+2*0xD, /* reset port */
1991/0704		};