NAME

SetICR: Cause, clear, and sample ICR interrupts.

SYNOPSIS

oldMask = SetICR( Resource, mask )
D0 A6 D0

WORD SetICR(struct Library *, WORD);

FUNCTION

This function provides a means of reseting, causing, and sampling 8520 CIA interrupt control registers.

INPUTS

mask: A bit mask indicating which interrupts to be effected. If bit 7 is clear the mask indicates interrupts to be reset. If bit 7 is set, the mask indicates interrupts to be caused. Bit positions are identical to those in 8520 ICR.

RESULT

oldMask: The previous interrupt register status before making the requested changes. To sample current status without making changes, call the function with a null parameter.

EXAMPLE

Get the interrupt mask:

mask = SetICR(0)

Clear serial port interrupt:

SetICR(0x08)

NOTES

The CIA resources are special in that there is more than one of them in the system. Because of this, the C language stubs in amiga.lib for the CIA resources require an extra parameter to specify which CIA resource to use. The synopsys for the amiga.lib stubs is as follows:

oldMask = SetICR( Resource, mask ) D0 A6 D0

WORD SetICR( struct Library *, WORD );

***WARNING***

Never read the contents of the CIA interrupt control registers directly. Reading the contents of one of the CIA interrupt control registers clears the register. This can result in interrupts being missed by critical operating system code, and other applications.

EXCEPTIONS

Setting an interrupt bit for an enabled interrupt will cause an immediate interrupt.