Browse Prior Art Database

Microprocessor Program Trace Control Utilizing I/O or Memory Mapped Trap Activation

IP.com Disclosure Number: IPCOM000051944D
Original Publication Date: 1981-Apr-01
Included in the Prior Art Database: 2005-Feb-11
Document File: 3 page(s) / 99K

Publishing Venue

IBM

Related People

Farrell, WR: AUTHOR [+2]

Abstract

A microprocessor (MPU) program trace control arrangement which utilizes I/O or memory mapped trap activation is described. Through appropriate hardware and software support, it enables monitoring software support activity by using instruction step and address compare.

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Microprocessor Program Trace Control Utilizing I/O or Memory Mapped Trap Activation

A microprocessor (MPU) program trace control arrangement which utilizes I/O or memory mapped trap activation is described. Through appropriate hardware and software support, it enables monitoring software support activity by using instruction step and address compare.

A simplified functional diagram of the hardware support is shown in Fig. 1. The pertinent hardware functions thereof are tabulated below. An example of support software is shown in Fig. 2. TABLE OF HARDWARE FUNCTION
1. An input using address X'0030' reads the trap lines and

enables determining which line caused a trap request.
2. An address comparator can be loaded via software by sending

the high and low address bytes to addresses X'0020' and

X'0010', respectively.
3. Sending 00 to address X'0040' resets all previous trap

enable types.
4. Sending 01 to address X'0040' enables activation of a trap

in conjunction with any write to address X'0030'. The 01

can be sent to X'0040' any time in the set-up procedure.

The write to X'0030' must be executed immediately prior to

the execution of the return instruction to the monitored

code. This enables tracing each instruction in a monitored

program because a delayed trap occurs after two operand

fetches.
5. Sending 02 to address X'0040' enables activation of a trap

in conjunction with a write to address X'0030' to reset

the previous trap request. This enables trapping on

addre...