Abstract: A data processing apparatus (102) includes a processor core (104) having a bank of registers (106). The bank of registers (106) include a set of registers that are used for the storage of stack operands. Instructions from a second instruction set specifying stack operands are translated by an instruction translator (108) into instructions of a first instruction set (or control signals corresponding to those instructions) specifying register operands. These translated instructions are then executed by the processor core (104). The instruction translator (108) has multiple mapping states for controlling which registers corresponding to which stack operands within the stack. Changes between mapping states are carried out in dependence of stack operands being added to or removed from the set of registers.

Abstract: A decoder is provided for generating N output signals, the decoder comprising a precharged gate structure arranged to receive two or more input signals and to generate N intermediate signals. In a precharge phase, the precharged gate structure is arranged to output the N intermediate signals at a first logic value, and in an evaluate phase the precharged gate structure is arranged to maintain a first intermediate signal at the first logic value, and to cause all other intermediate signals to transition to a second logic value. Further, self-timed logic is provided for receiving the N intermediate signals, and for generating the N output signals, the self-timed logic being arranged, during the precharge phase, to generate the N output signals at the second logic value, and during the evaluate phase to cause a first output signal corresponding to the first intermediate signal to transition to the first logic value.