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Diagnose and Multiple Retry Testing

IP.com Disclosure Number: IPCOM000074850D
Original Publication Date: 1971-Jun-01
Included in the Prior Art Database: 2005-Feb-23
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Frye, HE: AUTHOR

Abstract

A DIAGNOSE instruction may be used to allow software to check out multiple retry and/or retry during machine check or interrupt coding. With this instruction (which uses the standard RS format), the effective address (B2+D2) points to a table of control words. This table consists of double words and may contain an indefinite number. The first word of each double word has the following format: Bit Position 0-1 Unused 0-7 Set into CPU GP Stats 8-15 Set to cycle counter 16-17 Cycle counter controls 00-count CPU & I/O ROS cycles 01-count only I/O ROS cycles 10-count only CPU ROS cycles 11-no count, no counter overflow 18 If on, log on counter overflow. The log resides only in the internal buffer, but is transferred to Main Store at time of machine check interrupt. 19-31 ROS address to be executed.

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Diagnose and Multiple Retry Testing

A DIAGNOSE instruction may be used to allow software to check out multiple retry and/or retry during machine check or interrupt coding. With this instruction (which uses the standard RS format), the effective address (B2+D2) points to a table of control words. This table consists of double words and may contain an indefinite number. The first word of each double word has the following format: Bit Position 0-1 Unused 0-7 Set into CPU GP Stats 8-15 Set to cycle counter 16-17 Cycle counter controls 00-count CPU & I/O ROS cycles 01- count only I/O ROS cycles 10-count only CPU ROS cycles 11-no count, no counter overflow 18 If on, log on counter overflow. The log resides only in the internal buffer, but is transferred to Main Store at time of machine check interrupt. 19-31 ROS address to be executed.

The above is very similar to other DIAGNOSE instruction, the main differences being: 1) Target is always entered in CPU mode. 2) Trap back to diagnose always occurs on counter overflow. The second word of each double word has the following format: Bit Position 16 Count on specific channel 17 Start count on ROS compare 18 Count on selected channel (PB) 19-31 Desired ROS compare address.

Upon entry from I-Fetch, DIAGNOSE will read the first double-control word from the table. It sets the second half into the ROS compare register. It then sets the first half to the counter and sets up counter controls. It increments byte 0 of a general purp...