How many opcodes 6502?

How many opcodes 6502?

Of the 256 possible opcodes available using an 8-bit pattern, the original 6502 uses 151 of them, organized into 56 instructions with (possibly) multiple addressing modes. Depending on the instruction and addressing mode, the opcode may require zero, one or two additional bytes for operands.

How many opcodes does the NES have?

The 6502 has six processor registers. These are special data storage areas that are separate from the CPU’s address space. These registers allow the 6502 to execute instructions faster than it could if it only had access to system RAM. Each has a special role within the CPU.

How many registers does the 6502 have?

The program counter is a 16 bit register which points to the next instruction to be executed. The value of program counter is modified automatically as instructions are executed.

What still uses 6502?

The 6502 core has been used in toys, calculators, medical devices. I think toys is a major category. Recently I posted a finding that an optical mouse chip had a 6502 in it. There could easily be other embedded uses.

How much RAM can a 6502 address?

64K bytes
The 6502 is strictly an 8-bit architecture, with a single 8-bit accumulator register, and can access a maximum of 64K bytes of random access memory. Memory addresses are exactly 16 bits in length, because 216 = 65536 = 64K. Valid addresses range from 0 up to 65535.

Is the 6502 still made?

It’s Still in Production The Western Design Center, Inc, founded by Bill Mensch of Motorola and MOS fame, sells modern versions of the 6502 in both the classic 40 pin DIP package (appears to be pin-compatible with the original), as well as more modern surface mount packages.

Is 6502 still manufactured?

Which is the cross assembler for NMOS 6502?

Ophis assembler – Michael Martin’s “Ophis” is a cross-assembler for 65xx, supporting the stock 6502 opcodes, 65c02 extensions, and syntax for the undocumented opcodes in the NMOS 6502. (Syntax for these opcodes matches those given in the VICE team’s documentation.)

Which is open source assembler supports 6502 opcodes?

xa65: 6502 Cross Assembler- Andre Fachat’s open-source assembler is written in C and supports the standard 6502 opcode list, as well as the Rockwell R65C02 CMOS opcodes.

Is there a program manual for the 6502 assembly language?

A classic book, which may be the same as How to Program the Apple II Using 6502 Assembly Language. Western Design Center’s official programming manual has some introductory material and is free to download. One in a series of posts on the NintendoAge forum covering NES programming.

Which is the assembler for the 6502 microprocessor?

Imaginary 6502 – Matt Dawson’s web-based assembler with emulation of a simple SBC. DCC6502 – A code disassembler for the 6502 microprocessor. It features accurate cycle counting, fast table-based disassembly, portability, and special features for NES developers.