Re: [E3-hacking] [RFC][PATCH v2 1/5] omap1: Amstrad Delta: add FIQ handler for serial keyboard port interrupt processing

Hi Janusz,

My ARM's not used much these days so I don't know how much this matters and may be incorrect so I've cut down the CC list, but given it's a FIQ handler and speed matters...

+key: @Is it a keyboard interrupt?

• ldr r11, [r12,#GPIO_INTERRUPT_STATUS] @ get GPIO interrupt status
• and r10, r11, #MBRD_CLK_MASK @ reveal keyboard bit
• cmp r10, #MBRD_CLK_MASK @ is keyboard bit low?
• bne mdm @ no - spurious - try mdm

Couldn't that be an `ands' instruction if MBRD_CLK_MASK has one-bit set? Then the cmp could be deleted.

+state:

• ldr r10, [r9,#FIQ_STATE]
• cmp r10, #0 @ are we expecting start bit?
• bne data @ no - in data processing state

Similarly, an `ldrs' here would make the cmp redundant. There's other similar bits elsewhere.

Thanks for continuing with these E3 patches.

Cheers, Ralph.