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SubjectRE: Booting AMD Elan520 without BIOS
On Fri, 24 Nov 2000, Joan Bertran wrote:

> I think so, because I've read somewhere the kernel needs interrupts
> configured, but as kernel configures i8259 I don't know what is necessary,
> the IDT with interrupt service routines ?, sommething special about the chipset ?

I put the following familiar-looking code at the head of linuxbios for
mainboards that need to boot 2.2.x. It should look familiar, except of
course this is 32-bit gas-compatible code.


#define i8259delay jmp 1f ; 1:

movb $0x11,%al /*! initialization sequence*/
outb %al,$0x20 /*! send it to 8259A-1*/
i8259delay
outb %al,$0xA0 /*! and to 8259A-2*/
i8259delay
movb $0x20,%al /*! start of hardware int's
(0x20)*/
outb %al,$0x21
i8259delay
movb $0x28,%al /*! start of hardware int's 2
(0x28)*/
outb %al,$0xA1
i8259delay
movb $0x04,%al /*! 8259-1 is master*/
outb %al,$0x21
i8259delay
movb $0x02,%al /*! 8259-2 is slave*/
outb %al,$0xA1
i8259delay
movb $0x01,%al /*! 8086 mode for both*/
outb %al,$0x21
i8259delay
outb %al,$0xA1
i8259delay
movb $0xFF,%al /*! mask off all interrupts for
now*/
outb %al,$0xA1
i8259delay
movb $0xFB,%al /*! mask all irq's but irq2
which*/
outb %al,$0x21 /*! is cascaded*/



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