Intel iapx 432 manual

iAPX 432 Interface Processor Architecture Reference Manual

current status information. When operands are read from this subr ange or wr i tten into this subr ange, the processor data segment

is accessed. Data written into the part of the subrange representing the function request facility is captured when no

function is in progress. During function execution, Attached Processor software must not make further function requests.

At the base of the mapping facility area, the extra information for supporting block transfer via map entry 0 is recorded in a data structure with the following organization.

=		= double byte
1----------------		1	displacement
1	reserved	1 31
1--------------------------------	P. S. disp.	1
1	432 disp.	1
1		1
1--------------------------------	block count	1	28
1		1
=		=

When the transfer m:x1e subfield of the entry state field for map entry 0 indicates that it is in block transfer mode, the processor-resident copy of the block count field indicates the number of bytes remaining to be transferred for transfer termination

to occur normally (i. e. , upon count runout). Whenever normal transfer termination occurs, both copies of the block count field are zero. Whenever normal transfer termination does not occur, such as in the case of faults, both copies of the block count field indicate the number of remaining, but not transferred, bytes.

When the transfer mode subfield of the entry state field for map entry 0 indicates that it is in block transfer m:x1e, the processor-resident copy of the 432 displacement field indicates the displacement into the associated data segment of the next byte to be transferred.

When the transfer node subfield of the entry state field for map entry 0 indicates that it is in block transfer mode, the processor-resident copy of the Peripheral Subsystem displacement field indic~tes the displacement into the associated Peripheral Subsystem address range of the next byte to be transferred.

Any difference between the values of the tYfO displacement fields accounts for data in the processor-resident buffers which was not successfully transfered.

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