Message protocol
First Claim
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1. A method of non-intrusively monitoring data in a computer system comprising off-chip circuitry and on-chip circuitry, according to a message protocol in which the following four messages can be formulated:
- (i) a data write request in the form of a header byte of which two bits identify the nature of the message and six bits identify the word count of the number of data words to be written, an address word identifying an address location to which data is to be written, and a set of data words in accordance with the word count;
(ii) a data read request in the form of a header byte of which two bits identify the nature of the message and six bits identify the word count of the number of data words to be read, and an address word identifying an address location from which data is to be read;
(iii) a response message formulated with a header byte two bits of which identify the nature of the response message, six bits of which identify the word count and a plurality of data words in accordance with the word count representing data read from successive accessed memory locations; and
(iv) a diagnostic message indicating that a particular status of the off-chip or on-chip circuitry has been reached, the diagnostic message including a header byte the first two bits of which identify the nature of the message and the remaining six bits of which identify the reason for the diagnostic message, wherein said four messages (i)-(iv) provide diagnostic information non-intrusively between the off-chip circuitry and on-chip circuitry.
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Abstract
A method of effecting communication in a computer system between off-chip circuitry and on-chip circuitry is disclosed, according to a message protocol in which four messages can be formulated: a data write request; a data read request; a response message; and a diagnostic message.
25 Citations
19 Claims
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1. A method of non-intrusively monitoring data in a computer system comprising off-chip circuitry and on-chip circuitry, according to a message protocol in which the following four messages can be formulated:
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(i) a data write request in the form of a header byte of which two bits identify the nature of the message and six bits identify the word count of the number of data words to be written, an address word identifying an address location to which data is to be written, and a set of data words in accordance with the word count; (ii) a data read request in the form of a header byte of which two bits identify the nature of the message and six bits identify the word count of the number of data words to be read, and an address word identifying an address location from which data is to be read; (iii) a response message formulated with a header byte two bits of which identify the nature of the response message, six bits of which identify the word count and a plurality of data words in accordance with the word count representing data read from successive accessed memory locations; and (iv) a diagnostic message indicating that a particular status of the off-chip or on-chip circuitry has been reached, the diagnostic message including a header byte the first two bits of which identify the nature of the message and the remaining six bits of which identify the reason for the diagnostic message, wherein said four messages (i)-(iv) provide diagnostic information non-intrusively between the off-chip circuitry and on-chip circuitry. - View Dependent Claims (2, 4, 5, 6, 7, 8, 9, 10)
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3. A method of non-intrusively monitoring data in a computer system comprising off-chip circuitry and on-chip circuitry, according to a message protocol in which four message categories can be formulated, said message categories using a common header structure to convey different messages, the four message categories comprising:
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(i) a data write message category for data write requests, each data write request being in the form of a header byte of which two bits identify the nature of the message and six bits identify the word count of the number of data words to be written, an address word identifying an address location to which data is to be written, and a set of data words in accordance with the word count; (ii) a data read message category for data read requests, each data read request being in the form of a header byte of which two bits identify the nature of the message and six bits identify the word count of the number of data words to be read, and an address word identifying an address location from which data is to be read; (iii) a response message category for response messages, each response message being formulated with a header byte two bits of which identify the nature of the response message, six bits of which identify the word count and a plurality of data words in accordance with the word count, said plurality of data words representing data read from successive accessed memory locations; (iv) a diagnostic message category for diagnostic messages, each diagnostic message indicating that a particular status of the off-chip or on-chip circuitry has been reached, the diagnostic message including a header byte, the first two bits of which identify the nature of the message and the remaining six bits of which identify the reason for the diagnostic message wherein said off-chip circuitry and on-chip circuitry communicate diagnostic information non-intrusively using said four message categories. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17)
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18. A method of non-intrusively monitoring data in a computer system comprising off-chip circuitry and on-chip circuitry, according to a message protocol in which the following four messages can be formulated:
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(i) a data write request in the form of a header byte of which two bits identify the nature of the message and six bits identify the word count of the number of data words to be written, an address word identifying an address location to which data is to be written, and a set of data words in accordance with the word count; (ii) a data read request in the form of a header byte of which two bits identify the nature of the message and six bits identify the word count of the number of data words to be read, and an address word identifying an address location from which data is to be read; (iii) a response message formulated with a header byte two bits of which identify the nature of the response message, six bits of which identify the word count and a plurality of data words in accordance with the word count representing data read from successive accessed memory locations; and (iv) a diagnostic message indicating that a particular status of the off-chip or on-chip circuitry has been reached, the diagnostic message including a header byte the first two bits of which identify the nature of the message and the remaining six bits of which identify the reason for the diagnostic message, wherein said four messages (i)-(iv) provide diagnostic information non-intrusively between the off-chip circuitry and on-chip circuitry and wherein the four messages have a common header format, and the two bits identifying nature of the message have at least one of the following values including; a value of 00 identifying that the message is a data write request; a value of 01 identifying that the message is a data read request; a value of 10 identifying that the message is a response message; and a value of 11 identifying that the message is a diagnostic message.
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19. A method of non-intrusively monitoring data in a computer system comprising off-chip circuitry and on-chip circuitry, according to a message protocol in which four message categories can be formulated, said message categories using a common header structure to convey different messages, the four message categories comprising:
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(i) a data write message category for data write requests, each data write request being in the form of a header byte of which two bits identify the nature of the message and six bits identify the word count of the number of data words to be written, an address word identifying an address location to which data is to be written, and a set of data words in accordance with the word count; (ii) a data read message category for data read requests, each data read request being in the form of a header byte of which two bits identify the nature of the message and six bits identify the word count of the number of data words to be read, and an address word identifying an address location from which data is to be read; (iii) a response message category for response messages, each response message being formulated with a header byte two bits of which identify the nature of the response message, six bits of which identify the word count and a plurality of data words in accordance with the word count, said plurality of data words representing data read from successive accessed memory locations; (iv) a diagnostic message category for diagnostic messages, each diagnostic message indicating that a particular status of the off-chip or on-chip circuitry has been reached, the diagnostic message including a header byte, the firs two bits of which identify the nature of the message and the remaining six bits of which identify the reason for the diagnostic message wherein said off-chip circuitry and on-chip circuitry communicate diagnostic information non-intrusively using said four message categories and wherein the four message categories have a common header format, and the two bits identifying nature of the message have at least one of the following values including; a value of 00 identifying that the message is a data write message; a value of 01 identifying that the message is a data read message; a value of 10 identifying that the message is a response message; and a value of 11 identifying that the message is a diagnostic message.
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Specification