Abstract: Multi-dimensional parity checker (MDPC) systems and related methods are disclosed to check parity of data regions within external memories. In one embodiment, the MDPC system includes a control register and a parity checker. The parity checker receives data segments accessed from the data region. The parity checker generates and accumulates multi-dimensional parity bits for the data segments and subsequently compares accumulated bits to expected multi-dimensional parity bits to generate multi-dimensional error syndrome bits representing identified comparison errors. The parity checker also determines a syndrome state based upon the multi-dimensional syndrome bits and stores the syndrome state within the control register. The parity checker operates in different modes based upon different values stored in an operational mode field of the control register.

Abstract: Methods and systems are disclosed for key management for on-the-fly hardware decryption within an integrated circuit. Encrypted information is received from an external memory and stored in an input buffer within the integrated circuit. The encrypted information includes one or more encrypted key blobs. The encrypted key blobs include one or more secret keys for encrypted code associated with one or more encrypted software images stored within the external memory. A key-encryption key (KEK) code for the encrypted key blobs is received from an internal data storage medium within the integrated circuit, and the KEK code is used to generate one or more key-encryption keys (KEKs). A decryption system then decrypts the encrypted key blobs using the KEKs to obtain the secret keys, and the decryption system decrypts the encrypted code using the secret keys. The resulting decrypted software code is then available for further processing.

Abstract: Multi-dimensional parity checker (MDPC) systems and related methods are disclosed to check parity of data regions within external memories. In one embodiment, the MDPC system includes a control register and a parity checker. The parity checker receives data segments accessed from the data region. The parity checker generates and accumulates multi-dimensional parity bits for the data segments and subsequently compares accumulated bits to expected multi-dimensional parity bits to generate multi-dimensional error syndrome bits representing identified comparison errors. The parity checker also determines a syndrome state based upon the multi-dimensional syndrome bits and stores the syndrome state within the control register. The parity checker operates in different modes based upon different values stored in an operational mode field of the control register.

Abstract: Access requests to access data operands from memory space designated as a type of execute-only memory are allowed to precede in response to determining that the operand access request was generated using a particular type of addressing mode.

Abstract: Methods and systems are disclosed for on-the-fly decryption within an integrated circuit that adds zero additional cycles of latency within the overall decryption system performance. A decryption system within a processing system integrated circuit generates an encrypted counter value using an address while encrypted code associated with an encrypted software image is being obtained from an external memory using the address. The decryption system then uses the encrypted counter value to decrypt the encrypted code and to output decrypted code that can be further processed. A secret key and an encryption engine can be used to generate the encrypted counter value, and an exclusive-OR logic block can process the encrypted counter value and the encrypted code to generate the decrypted code. By pre-generating the encrypted counter value, additional cycle latency is avoided. Other similar data independent encryption/decryption techniques can also be used such as output feedback encryption/decryption modes.

Abstract: Methods and systems are disclosed for on-the-fly decryption within an integrated circuit that adds zero additional cycles of latency within the overall decryption system performance. A decryption system within a processing system integrated circuit generates an encrypted counter value using an address while encrypted code associated with an encrypted software image is being obtained from an external memory using the address. The decryption system then uses the encrypted counter value to decrypt the encrypted code and to output decrypted code that can be further processed. A secret key and an encryption engine can be used to generate the encrypted counter value, and an exclusive-OR logic block can process the encrypted counter value and the encrypted code to generate the decrypted code. By pre-generating the encrypted counter value, additional cycle latency is avoided. Other similar data independent encryption/decryption techniques can also be used such as output feedback encryption/decryption modes.

Abstract: Methods and systems are disclosed for key management for on-the-fly hardware decryption within an integrated circuit. Encrypted information is received from an external memory and stored in an input buffer within the integrated circuit. The encrypted information includes one or more encrypted key blobs. The encrypted key blobs include one or more secret keys for encrypted code associated with one or more encrypted software images stored within the external memory. A key-encryption key (KEK) code for the encrypted key blobs is received from an internal data storage medium within the integrated circuit, and the KEK code is used to generate one or more key-encryption keys (KEKs). A decryption system then decrypts the encrypted key blobs using the KEKs to obtain the secret keys, and the decryption system decrypts the encrypted code using the secret keys. The resulting decrypted software code is then available for further processing.

Abstract: Access requests to access data operands from memory space designated as a type of execute-only memory are allowed to precede in response to determining that the operand access request was generated using a particular type of addressing mode.

Abstract: A processor begins exception processing in response to an exception event. Exception processing by the processor is halted during exception processing to facilitate debugging. The exception event can be a reset exception event or an interrupt exception event. Normal exception processing by the data processor can be resumed after debugging, or exception processing by the data processor can be aborted to allow the normal execution of instructions by the data processor to resume. An exception event can be selectively treated as an interrupt or a reset.

Abstract: A processor begins exception processing in response to an exception event. Exception processing by the processor is halted during exception processing to facilitate debugging. The exception event can be a reset exception event or an interrupt exception event. Normal exception processing by the data processor can be resumed after debugging, or exception processing by the data processor can be aborted to allow the normal execution of instructions by the data processor to resume. An exception event can be selectively treated as an interrupt or a reset.

Abstract: A branch cache (40) has a plurality of storage levels (120, 122, 140, and/or 142) wherein at least two write registers (114 and 116) are used to perform a parallel write operation to at least two of the storage levels in the plurality of storage levels (120, 122, 140, and/or 142). The two write registers (114 and 116) are provided due to the fact that the branch cache 40 is implemented as a multi-state (typically five state--see FIG. 5) branch prediction unit having instruction folding. Instruction folding, as taught herein, allows a branch instruction which is predicted as being taken to be executed along with an instruction that precedes the branch in execution flow. The instruction which directly precedes the branch in execution flow is usually the instruction which is used to "fold" the branch. Effectively, this instruction folding allows branches, which are predicted as being taken, to be executed in zero clock cycles.