Scan chain for shifting the state of a processor into memory at a specified point during system operation for testing purposes

In a processor of a computer system used for processing data, wherein the data is stored in a first memory of the computer system, a method for accessing the first memory at a particular point of execution during system operation, comprising the steps of:

• stalling the processor at that particular point of execution;
• specifying an address corresponding to a location of the memory that is to be read;
• generating a command signal to read data from the memory stored at the specified address;
• loading the data into a second memory;
• shifting out the data from the second memory.

A semiconductor chip comprising:

• a processor for processing data;
• a RAM coupled to the processor for storing the data;
• a plurality of registers coupled to the RAM for storing the data;
• a stall controller for stalling the processor during system operation in order to test the processor;
• a RAM controller coupled to the RAM memory for causing data stored in the RAM to be loaded into the registers when the processor is stalled;
• a scan chain coupled to the plurality of registers, wherein the scan chain serially shifts out the bits of data stored in the registers after the registers have been loaded with data from the RAM, wherein contents of the RAM is determined by examining the data shifted out by the scan chain.