Re: base_irq_inittab.S

• To: oskit-users@fast.cs.utah.edu, rogelio@evoserve.com
• Subject: Re: base_irq_inittab.S
• From: Mike Hibler <mike>
• Date: Fri, 24 Nov 2000 16:33:16 -0700 (MST)
• Sender: owner-oskit-users@fast.cs.utah.edu

> Date: Sat, 25 Nov 2000 06:57:41 +0800
> To: oskit-users@fast.cs.utah.edu
> Subject: base_irq_inittab.S
> From: "Rogelio M. Serrano Jr." <rogelio@evoserve.com>
> 
> In oskit-20000901/kern/x86/pc/base_irq_inittab.S:
> 
> 116        /* Save the current master PIC mask (bl) */
> 117        inb     $0x21,%al
> 118----->  movb    %al,%bl
> 
> What is the purpose of saving the PIC mask in bl? That value seems unused in later processing. Can I remove that line?
> 

In the common case, the mask is restored down around line 200:

        /* Unmask the IRQ if the return value from the handler allows it */
        testl   $BASE_IRQ_LEAVE_MASKED,%edx
        jne     1f
        movb    %bl,%al
        outb    %al,$0x21

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