Abstract: Improved systems and methods of authenticating a user using a mobile device to access a secure electronic portal are provided. A user may be enabled to quickly and securely log onto a website or other electronic portal using a handheld electronic device. In certain embodiments, multifactor authentication is utilized to improve the security of the authentication process.

Abstract: Improved systems and methods of authenticating a user using a mobile device to access a secure electronic portal are provided. A user may be enabled to quickly and securely log onto a website or other electronic portal using a handheld electronic device. In certain embodiments, multifactor authentication is utilized to improve the security of the authentication process.

Abstract: A target computing system performs program code conversion from subject code, executable by a subject computing architecture, into target code executable by the target computing system, and then executes the target code. The target system handles exceptions during binding to native code. Native code binding executes a portion of native code in place of translating a portion of the subject code into the target code. Upon an exception during execution of the portion of native code, the target system saves a target state representing a current point of execution for the portion of native code, and creates a subject state representing an emulated point of execution in the subject architecture. A subject exception handler handles the exception with reference to the subject state. Upon resuming execution from the exception using the subject state, the saved target state is restored to resume execution in the section of portion of native code.

Abstract: Precise exception handling relies on a precise subject state including an accurate program counter and register values of a subject processor. Subject code (17) is translated into target code (21) executable by a target processor (13). The generated target code (17) includes counterpart target instructions (214) associated with fault-vulnerable subject code instructions (174). Further, each of the counterpart target code instruction (214) is associated with recovery information (195). When an exception (e.g. a fault) occurs, the recovery information (195) is retrieved and used to recover a precise subject state, in particular by taking account of optimizations to generate the common-case target code (21). The precise subject state is then used to precisely handle the exception.

Abstract: An execution control method is described for use in a translator (19) which converts subject code (17) into target code (21). The translator (19) includes a translator trampoline function (191) which is called from a translator run loop (190) and which in turn calls either to a translator code generator (192) to generate target code, or else calls previously generated target code (212) for execution. Control then returns to the translator trampoline function (191) to make a new call, or returns to the translator run loop (190). Other aspects include making context switches through the trampoline function (191) and setting first and second calling conventions either side of the trampoline function (191). Jumping directly or indirectly between target code blocks (212) during execution is also described.