Abstract: A microprocessor includes a first branch condition state and a second branch condition state. The microprocessor also includes a conditional branch instruction of a first type that instructs the microprocessor to wait to correctly resolve the conditional branch instruction of the first type based on the first branch condition state until other instructions within the microprocessor that update the first branch condition state and that are older than the conditional branch instruction of the first type have updated the first branch condition state. A conditional branch instruction of a second type instructs the microprocessor to correctly resolve the conditional branch instruction of the second type based on the second branch condition state without regard to whether other instructions within the microprocessor that update the second branch condition state and that are older than the conditional branch instruction of the second type have yet updated the second branch condition state.

Abstract: A microprocessor includes a memory that stores instructions of a non-user program to implement a user program instruction of the user-visible instruction set of the microprocessor. The non-user program includes a conditional branch instruction. A first fetch unit fetches instructions of the user program that includes the instruction that is implemented by the non-user program. An instruction decoder decodes the user program instructions and saves a state in response to decoding the user program instruction that is implemented by the non-user program. An execution unit executes the user program instructions fetched by the first fetch unit and executes instructions of the non-user program other than the conditional branch instruction. A second fetch unit fetches the non-user program instructions from the memory and resolves the conditional branch instruction based on the saved state without sending the conditional branch instruction to the execution unit to resolve the conditional branch instruction.

Abstract: A microprocessor includes a pipeline of stages for processing instructions and first and second types of conditional branch instruction includable by a program. The microprocessor makes a prediction of conditional branch instructions of the first type and flushes the pipeline of instructions if the prediction is subsequently determined to be incorrect, thereby incurring a branch misprediction penalty related to processing of conditional branch instructions of the first type. The microprocessor always correctly resolves conditional branch instructions of the second type without making a prediction of conditional branch instructions of the second type, thereby avoiding ever incurring a branch misprediction penalty related to processing of conditional branch instructions of the second type.

Abstract: A microprocessor has a microcode memory for storing original microcode instructions to implement user program instructions, and an interface to an external memory for storing a microcode patch. The microcode patch includes substitute microcode instructions and validation information. The microprocessor includes a private random access memory (PRAM), addressable by the original and substitute microcode instructions but not addressable by user program instructions. The microprocessor also includes patch hardware, which conditionally receives the substitute microcode instructions. The microprocessor executes the substitute microcode instructions when applied to the patch hardware instead of corresponding original microcode instructions.

Abstract: A microprocessor that includes a random number generator (RNG) that saves and restores its own state on a task switch without operating system (OS) support. The RNG includes a control and status register (CSR) for storing control values that affect the generation of random numbers. The CSR is not saved and restored by the OS. The RNG shadows the CSR with an SSE register that is saved and restored by the OS. A new instruction loads the CSR, and also loads the shadowed SSE register. Whenever the SSE register is restored from memory, the RNG sets a flag indicating that a possible task switch occurred. Whenever the processor executes a new instruction that stores the random data to memory, it checks the flag and copies the control values from the SSE register to the CSR if the flag is true, discards previously generated bytes, and restarts random number generation.

Abstract: A microprocessor includes an instruction translator that translates a store macroinstruction into exactly one fused store microinstruction. The store macroinstruction in the microprocessor's macroarchitecture macroinstruction set instructs the microprocessor to store data from a general purpose register of the microprocessor to a memory location. The fused store microinstruction is an instruction in the microprocessor's microarchitecture microinstruction set. A reorder buffer (ROB) receives the fused store microinstruction from the instruction translator into exactly one of its plurality of entries. An instruction dispatcher dispatches for execution a store address microinstruction and a store data microinstruction to different respective execution units of the microprocessor in response to receiving the fused store microinstruction. Neither the store address microinstruction nor the store data microinstruction occupy any of the ROB entries.

Abstract: A microprocessor having model specific registers (MSRs) includes, for each of the MSRs, an associated default value that indicates whether the MSR is protected or non-protected and an associated fuse that, if blown, toggles the associated default value from protected to non-protected or non-protected to protected. In one embodiment, microcode that does the following in response to the microprocessor encountering an instruction that accesses a specified MSR: determines whether the fuse associated with the specified MSR is blown or unblown, uses the default value associated with the MSR as an indicator of whether the MSR is protected if the associated fuse is unblown; toggles the associated default value to generate the indicator if the associated fuse is blown; protects access to the MSR if the indicator indicates the MSR is protected; and refrains from protecting access to the MSR if the indicator indicates the MSR is non-protected.

Abstract: A microprocessor REP MOVS macroinstruction specifies the word length of the string in the IA-32 ECX register. The microprocessor includes a memory, configured to store a first and second sequence of microinstructions. The first sequence conditionally transfers control to a microinstruction within the first sequence based on the ECX register. The second sequence does not conditionally transfer control based on the ECX register. The microprocessor includes an instruction translator, coupled to the memory. In response to a macroinstruction that moves an immediate value into the ECX register, the instruction translator sets a flag and saves the immediate value. In response to a macroinstruction that modifies the ECX register in a different manner, the translator clears the flag. In response to a REP MOVS macroinstruction, the instruction translator transfers control to the first sequence if the flag is clear; and transfers control to the second sequence if the flag is set.

Abstract: A microprocessor includes re-writeable non-volatile state (RNS) addressable by an instruction executed by the microprocessor that instructs the microprocessor to write a new value to the RNS. A plurality of fuses are each readable to determine whether the fuse is blown or unblown, in response to the microprocessor decoding the instruction. A Boolean logic unit performs Boolean operations on the values read from the plurality of fuses to determine a current RNS value. A fuse blowing device blows at least one unblown fuse to change the current RNS value to the new value when the new value is different than the current value. The microprocessor can read the plurality of fuses, perform the Boolean operations, and blow at least one unblown fuse to change the current value of the RNS to a new value multiple times in response to a program running on the microprocessor executing the instruction multiple times.

Abstract: A technique is provided for performing modular multiplication. In one embodiment, an apparatus in a microprocessor is provided for accomplishing modular multiplication operations. The apparatus includes translation logic and execution logic. The translation logic receives an atomic Montgomery multiplication instruction from a source therefrom, where the atomic Montgomery multiplication instruction prescribes generation of a Montgomery product. The translation logic translates the atomic Montgomery multiplication instruction into a sequence of micro instructions specifying sub-operations required to accomplish generation of the Montgomery product. The execution logic is operatively coupled to the translation logic. The execution logic receives the sequence of micro instructions, and performs the sub-operations to generate the Montgomery product.

Abstract: An apparatus and method are provided for extending a microprocessor instruction set to specify non-temporal memory references at the instruction level. The apparatus includes translation logic and extended execution logic. The translation logic translates an extended instruction into a micro instruction sequence. The extended instruction has an extended prefix and an extended prefix tag. The extended prefix specifies a non-temporal access for a memory reference prescribed by the extended instruction, where the non-temporal access cannot be specified by an existing instruction from an existing instruction set. The extended prefix tag indicates the extended prefix, where the extended prefix tag is an otherwise architecturally specified opcode within the existing instruction set. The extended execution logic is coupled to the translation logic. The extended execution logic receives the micro instruction sequence, and executes the non-temporal access to perform the memory reference.

Abstract: An apparatus and method are provided for extending a microprocessor instruction set to allow for selective suppression of store checking at the instruction level. The apparatus includes fetch logic, and translation logic. The fetch logic receives an extended instruction. The extended instruction has an extended prefix and an extended prefix tag. The extended prefix specifies that store checking be suppressed for the extended instruction. The extended prefix tag is an otherwise architectural opcode within an existing instruction set. The fetch logic precludes store checking for pending store events associated with the extended instruction. The translation logic is coupled to the fetch logic. The translation logic translates the extended instruction into a micro instruction sequence that sequence directs the microprocessor to exclude store checking during execution of a prescribed operation.

Abstract: A microprocessor includes re-writeable non-volatile state (RNS) addressable by an instruction executed by the microprocessor that instructs the microprocessor to write a new value to the RNS. A plurality of fuses are each readable to determine whether the fuse is blown or unblown, in response to the microprocessor decoding the instruction. A Boolean logic unit performs Boolean operations on the values read from the plurality of fuses to determine a current RNS value. A fuse blowing device blows at least one unblown fuse to change the current RNS value to the new value when the new value is different than the current value. The microprocessor can read the plurality of fuses, perform the Boolean operations, and blow at least one unblown fuse to change the current value of the RNS to a new value multiple times in response to a program running on the microprocessor executing the instruction multiple times.

Abstract: An apparatus providing for a secure execution environment including a microprocessor and a secure non-volatile memory. The microprocessor executes non-secure application programs and a secure application program, where the non-secure application programs are accessed from a system memory via a system bus, and where the secure application program is executed in a secure execution mode. The microprocessor has secure watchdog logic that monitors environmental attributes corresponding to the microprocessor and to the secure application program, and that is configured to transfer program control to one of a plurality of event handlers within the secure application program. The secure non-volatile memory is coupled to the microprocessor via a private bus.

Abstract: An apparatus providing for a secure execution environment. The apparatus includes a microprocessor and an external crystal. The microprocessor is configured to execute non-secure application programs and a secure application program, where the non-secure application programs are accessed from a system memory via a system bus and the secure application program is accessed from a secure non-volatile memory via a private bus coupled to the microprocessor. The microprocessor has a secure real time clock that is configured to provide a persistent time, where the secure real time clock is only visible and accessible by the secure application program when the microprocessor is executing in a secure mode. The external crystal is coupled to the secure real time clock within the microprocessor and is configured to cause an oscillator within the secure real time clock to generate an oscillating output voltage that is proportional to the frequency of the external crystal.

Abstract: An apparatus providing for a secure execution environment including a microprocessor and a secure non-volatile memory. The microprocessor is configured to execute non-secure application programs and a secure application program, where the non-secure application programs are accessed from a system memory via a system bus. The microprocessor has secure execution mode logic that is configured to detect execution of a secure execution mode return event, and that is configured to terminate a secure execution mode within the microprocessor, where the secure execution mode exclusively supports execution of the secure application program.

Abstract: An apparatus providing for a secure execution environment. The apparatus includes a microprocessor and a secure non-volatile memory. The microprocessor is configured to execute non-secure application programs and a secure application program, where the non-secure application programs are accessed from a system memory via a system bus. The secure non-volatile memory is coupled to the microprocessor via a private bus. The secure non-volatile memory is configured to store the secure application program, where transactions over the private bus between the microprocessor and the secure non-volatile memory are isolated from the system bus and corresponding system bus resources within the microprocessor.

Abstract: An apparatus providing for a secure execution environment including a microprocessor and a secure non-volatile memory. The microprocessor executes non-secure application programs and a secure application program. The non-secure application programs are accessed from a system memory via a system bus, and the secure application program is executed in a secure execution mode. The microprocessor has a watchdog manager that monitors environments of the microprocessor by noting and evaluating data communicated by a plurality of monitors, and that classifies the data to indicate a security level associated with execution of the secure application program, and that directs secure execution mode logic to perform responsive actions in accordance with the security level. The secure non-volatile memory is coupled to the microprocessor via a private bus, and stores the secure application program.

Abstract: An apparatus providing for a secure execution environment, including a microprocessor and a secure non-volatile memory. The microprocessor executes non-secure application programs and a secure application program, where the non-secure application programs are accessed from a system memory via a system bus. The microprocessor has secure execution mode logic that is configured to provide for a secure execution mode within the microprocessor for execution of the secure application program. The secure execution mode logic records the state of the microprocessor in a non-volatile indicator register upon entry into the secure execution mode and upon exit from the secure execution mode. The secure non-volatile memory is coupled to the microprocessor via a private bus and is configured to store the secure application program. Transactions over the private bus between the microprocessor and the secure non-volatile memory are isolated from the system bus and corresponding system bus resources within the microprocessor.

Abstract: An apparatus providing for a secure execution environment. The apparatus includes a microprocessor that is configured to execute non-secure application programs and a secure application program, where the non-secure application programs are accessed from a system memory via a system bus. The microprocessor has a non-secure memory and a secure volatile memory. The non-secure memory is configured to store portions of the non-secure application programs for execution by the microprocessor, where the non-secure memory is observable and accessible by the non-secure application programs and by system bus resources within the microprocessor. The secure volatile memory is configured to store the secure application program for execution by the microprocessor, where the secure volatile memory is isolated from the non-secure application programs and the system bus resources within the microprocessor.