Abstract: A small hardware implementation is provided for the Advanced Encryption Standard SubByte function that implements the affine transform and inverse transform in a single Affine-All transform using a multiplicative inverse ROM. The logic is greatly reduced and the maximum path delay is reduced compared to a multiplexor implementation and is slightly greater than a ROM implementation.

Abstract: A circuit arrangement and method facilitate the execution of switch instructions such as Java lookupswitch and tableswitch instructions in hardware through emulation of such instructions using a plurality of conditional branch instructions from the same instruction set as the switch instructions, and which are capable of being directly implemented in hardware. The conditional branch instructions are typically generated by switch instruction handling logic and passed to execution logic capable of natively executing the conditional branch instructions. By emulating a complex switch instruction in switch instruction handling logic using a plurality of conditional branch instructions from the same instruction set, often the amount of custom circuitry needed to fully support a complex switch instruction is substantially reduced from what would be required to natively support the switch instruction in the execution logic of a hardware processor.

Abstract: An expansion module for a Handspring Visor includes a multi-master AMBA Advanced System Bus (ASB). The Springboard bus of the visor is coupled to the ASB bus via Springboard-to-ASB-bus bridge. This bridge includes a protocol translator and a second Arm7 to ASB interface. The protocol translator translates bi-directionally between the Springboard bus protocol and the Arm7TDMI protocol. The translator includes an interface to the Springboard bus and a state machine. The state machine coordinates data transfers between the buses. The state machine also monitors signals indicating when each of the buses begins to treat a data transfer as complete so that the data transfer can be validated or flagged as an error condition. A programmable counter adjusts maximum counts to compensate for different clock frequencies in measuring a write-wait state duration to ensure valid writes from the Visor to the ASB bus.

Abstract: An expansion module for a Handspring Visor (which conforms to the Springboard bus specification) includes a multi-master AMBA Advanced System Bus (ASB). Optionally, an Arm7 processor is attached to this bus via an Arm7 to ASB interface as one master. The Springboard bus of the visor is coupled to the ASB bus via a Springboard-to-ASB-bus bridge. This bridge comprises a protocol translator and a second Arm7 to ASB interface. The protocol translator translates bi-directionally between the Springboard bus protocol and the Arm7TDMI protocol. The translator includes an interface to the Springboard bus and a state machine. The state machine coordinates data transfers between the buses. The state machine also monitors signals indicating when each of said buses begins to treat a data transfer as complete so that the data transfer can be validated or flagged as an error condition.

Abstract: A circuit arrangement and method facilitate the execution of switch instructions such as Java lookupswitch and tableswitch instructions in hardware through emulation of such instructions using a plurality of conditional branch instructions from the same instruction set as the switch instructions, and which are capable of being directly implemented in hardware. The conditional branch instructions are typically generated by switch instruction handling logic and passed to execution logic capable of natively executing the conditional branch instructions. By emulating a complex switch instruction in switch instruction handling logic using a plurality of conditional branch instructions from the same instruction set, often the amount of custom circuitry needed to fully support a complex switch instruction is substantially reduced from what would be required to natively support the switch instruction in the execution logic of a hardware processor.

Abstract: An expansion module for a Handspring Visor (which conforms to the Springboard bus specification) includes a multi-master AMBA Advanced System Bus (ASB). Optionally, an Arm7 processor is attached to this bus via an Arm7 to ASB interface as one master. The Springboard bus of the visor is coupled to the ASB bus via a Springboard-to-ASB-bus bridge. This bridge comprises a protocol translator and a second Arm7 to ASB interface. The protocol translator translates bi-directionally between the Springboard bus protocol and the Arm7TDMI protocol. The translator includes an interface to the Springboard bus and a state machine. The state machine coordinates data transfers between the buses. The state machine also monitors signals indicating when each of said buses begins to treat a data transfer as complete so that the data transfer can be validated or flagged as an error condition.