Abstract: Fast access of a memory having a stack uses an address bit, a stack pointer, and fast access random access memory (“RAM”). When a first address mode is used in conjunction with the address bit and the stack pointer, the location of the access RAM can be shifted in order to achieve an index of a literal offset address mode.

Abstract: A microcontroller apparatus is provided with an instruction set for manipulating the behavior of the microcontroller. The apparatus and system is provided that enables a linearized address space that makes modular emulation possible. Direct or indirect addressing is possible through register files or data memory. Special function registers, including the Program Counter (PC) and Working Register (W), are mapped in the data memory. An orthogonal (symmetrical) instruction set makes possible any operation on any register using any addressing mode. Consequently, two file registers to be used to some two operand instructions. This allows data to be moved directly between two registers without going through the W register. Thus, increasing performance and decreasing program memory usage.

Abstract: A processor processes a variable cycle interrupt disable instruction DISI X is provided. The instruction disables interrupt processing for a variable number of processor cycles corresponding to the value specified by the instruction operand X. The DISI X instruction may be strategically used by programmers to prevent interrupts from being taken during certain intervals within a program.

Abstract: A microcontroller apparatus is provided with an instruction set for manipulating the behavior of the microcontroller. The apparatus and system is provided that enables a linearized address space that makes modular emulation possible. Direct or indirect addressing is possible through register files or data memory. Special function registers, including the Program Counter (PC) and Working Register (W), are mapped in the data memory. An orthogonal (symmetrical) instruction set makes possible any operation on any register using any addressing mode. Consequently, two file registers to be used to some two operand instructions. This allows data to be moved directly between two registers without going through the W register. Thus, increasing performance and decreasing program memory usage.

Abstract: A processor has an architecture that provides the processing speed advantages of the Harvard architecture, but does not require special purpose instructions or two separate external memories in order to expand both data memory and program instruction memory. The processor has separate program memory space and data memory space, but provides the capability to map at least a portion of the program memory space to the data memory space. This allows most program instructions that are processed to obtain the speed advantages of simultaneous program instruction and data access, yet provides a means to access program memory resident data without special purpose instructions. It also allows program memory space and data memory space to be expanded externally to the processor using only one external memory device that includes both program instructions and data.

Abstract: A processor is provided that has a data memory that may be addressed as a dual memory space in one mode and as a single linear memory space in another mode. The memory may permit dual concurrent operand fetches from the data memory when DSP instructions are processed. The memory may then dynamically permit the same memory to be accessed as a single linear memory address space for non-DSP instructions.

Abstract: An instruction set is provided that features ninety four instructions and various address modes to deliver a mixture of flexible micro-controller like instructions and specialized digital signal processor (DSP) instructions that execute from a single instruction stream.

Abstract: A processor configuration for processing multi-precision shift instructions is provided. The multi-precision shift instructions are executed following a previous shift instruction of the same increment, such as a logical or arithmetic left or right shift operation. The first shift instruction shifts a first memory word by the shift increment and stores this shifted value into memory. The second, and any subsequent, multi-precision shift instruction shifts the next memory word by the shift increment and concatenates the bits shifted out of the previously shifted memory word into bit positions of the memory word presently being shifted. This concatenated value is then stored back to memory and forms another part of the multi-precision shifted value.

Abstract: A processor processes a variable cycle interrupt disable instruction DISI X is provided. The instruction disables interrupt processing for a variable number of processor cycles corresponding to the value specified by the instruction operand X. The DISI X instruction may be strategically used by programmers to prevent interrupts from being taken during certain intervals within a program.

Abstract: A processor has an architecture that provides the processing speed advantages of the Harvard architecture, but does not require special purpose instructions or two separate external memories in order to expand both data memory and program instruction memory. The processor has separate program memory space and data memory space, but provides the capability to map at least a portion of the program memory space to the data memory space. This allows most program instructions that are processed to obtain the speed advantages of simultaneous program instruction and data access, yet provides a means to access program memory resident data without special purpose instructions. It also allows program memory space and data memory space to be expanded externally to the processor using only one external memory device that includes both program instructions and data.