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Program Monitoring Technique,

IP.com Disclosure Number: IPCOM000073726D
Original Publication Date: 1971-Jan-01
Included in the Prior Art Database: 2005-Feb-23
Document File: 3 page(s) / 47K

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Flanagan, HW: AUTHOR


The MC instruction in the drawings may be used to signal a monitoring operation during execution of a computer program.

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Program Monitoring Technique,

The MC instruction in the drawings may be used to signal a monitoring operation during execution of a computer program.

A programmer can insert the MC instruction at different places in his program where monitoring is desired. The programmer also can tailor each insertion of the instruction with a unique identification by using its G and H fields to identify a function which occurs near the insertion point. For example, the MC instruction may be inserted next to any instruction, or with any block of code, to identify it, and the time, frequency, or other characteristic of its execution.

The H field can provide an identifier which is initially programmed into the instruction. The G field specifies a general register G, which permits an identifier to be later programmed for use during an execution of the MC instruction. If the G field is zero, no general register is specified, and then the H field entirely provides the identification. If H is zero, and G is not zero, register G entirely provides the identification. If both fields G and H are nonzero, the H field is added to the contents of register G, i.e. (G) + H, to provide a single identifier.

When executed, the MC instruction causes a computer hardware interrupt which can link to a monitoring program or device. Its execution also causes its identifier to be posted at a predetermined memory location for use by a monitoring program or device.

For more detail, reference is made to the flow diagram in the drawings. Step 10 is entered when execution starts for any MC instruction when its op code is detected. Step 11 then examines the state of an MC control bit in the PSW shown. The PSW control bit can provide overall system control over whether a monitoring operation is permitted during execution of the program. If the PSW control bit is zero, the MC instruction is thereafter ignored (it is executed as a NOP) by entering step 12 which causes the program execution to go to the next instruction.

If the PSW control bit is set to one, step 13 is entered, and the I field within the MC instruction is used to address one of 16 mask bits in the mask field in a control register C. The purpose of the mask field is to permit selective control...