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The 6502 instruction set includes BRK (opcode $00), which is technically a software interrupt (similar in spirit to the SWI mnemonic of the Motorola 6800 and ARM processors). BRK is most often used to interrupt program execution and start a machine language monitor for testing and debugging during software development.
The CSG 65CE02 is an 8/16-bit microprocessor developed by Commodore Semiconductor Group in 1988. [1] It is a member of the MOS Technology 6502 family, developed from the CMOS WDC 65C02 released by the Western Design Center in 1983.
The most significant byte (MSB) of the aborted instruction's address is pushed onto the stack. The least significant byte (LSB) of the aborted instruction's address is pushed onto the stack. The status register is pushed onto the stack. The interrupt disable flag is set in the status register. PB is loaded with $00.
The Western Design Center (WDC) 65C02 microprocessor is an enhanced CMOS version of the popular nMOS-based 8-bit MOS Technology 6502.It uses less power than the original 6502, fixes several problems, and adds new instructions.
For instance, the MOS 6502 has eight instructions for performing addition, differing only in where they collect their operands. [2] Actually making these instructions work required circuitry in the CPU, which was a significant limitation in early designs and required designers to select just those instructions that were really needed.
The Mitsubishi 740 family has a processor core that executes a superset of the 6502 instruction set including many of the extensions added in the 65C02. There is a core set of new instructions common across all 740 family members, plus other instructions that exist in specific parts. [1]
An instruction set architecture (ISA) is an abstract model of a computer, also referred to as computer architecture.A realization of an ISA is called an implementation.An ISA permits multiple implementations that may vary in performance, physical size, and monetary cost (among other things); because the ISA serves as the interface between software and hardware.
The 6507 uses a 28-pin configuration, with 13 address pins (A0..A12) and 8 data pins (D0..D7). The seven remaining pins are used for power (Vss, Vcc), the CPU timing clock (φ0, φ2), to reset the CPU (the /RES pin), to request a CPU wait state during its next memory read access (the RDY pin), and for the CPU to indicate if a read or write memory (or MMIO device) access is being performed (the ...