What is the meaning of ORG $1000 when writing the code?
ORG $1000: this tells the assembler that this program will be located and organized in memory at address $1000. START: this is the first instruction of the program, it is also considered a subroutine.
Why we are using assemblers?
Today, assembly language is used primarily for direct hardware manipulation, access to specialized processor instructions, or to address critical performance issues. Typical uses are device drivers, low-level embedded systems, and real-time systems.
What is the 68000 processor addressing modes?
The memory of a 68000 computer is organized in 16-bit words and is byte-addressable. Two consecutive words can be interpreted as a single 32-bit long word. Memory addresses are assigned as shown in the above diagram.
How much memory can a 68000 address?
As you know, the 68000 has a 32 bit Program Counter and 32 bit address registers. This is so because addresses of locations in memory are 32 bit numbers, and consequently you can address up to 232 locations, i.e. 232 bytes, or 4 gigabytes (each memory location is one byte).
Does the 68000 have cache?
Just to chime in with more 68k nostalgia and trivia: The 68000 didn’t have cache – but 68010 did. Three whole instructions worth of cache.
What is D0 in assembly language?
| Assembly language instruction | RTL form |
|---|---|
| MOVE.B D0,D1 | [D1(0:7)] <- [D0(0:7)] |
| MOVE.W D0,D1 | [D1(0:15)] <- [D0(0:15)] |
| MOVE.L D0,D1 | [D1(0:31)] <- [D0(0:31)] |
What is machine code written in?
binary
It is usually written in binary. Machine code is the lowest level of software. Other programming languages are translated into machine code so the computer can execute them.
How many classes of registers does the 68000 have *?
The Motorola 68000 processor has 18 registers that are directly accessible by the user. Those are: 8 general-purpose data registers numbered from D0 to D7. 8 address registers numbered from A0 to A7.
What is a Motorola 68000 microprocessor?
The Motorola 68000 seriesis a family of 32-bit complex instruction set computer (CISC) microprocessors. During the 1980s and early 1990s, they were popular in personal computers and workstations and were the primary competitors of Intel’s x86 microprocessors.
What is an encrypted 68000 key?
Encrypted variants of the 68000, being the Hitachi FD1089 and FD1094, store decryption keys for opcodes and opcode data in battery-backed memory and were used in certain Sega arcade systems including System 16 to prevent piracy and illegal bootleg games.
What kind of bus does a Motorola 68EC000 controller have?
Motorola 68EC000 controller The 68EC000 is a low-cost version of the 68000 with a slightly different pinout, designed for embedded controller applications. The 68EC000 can have either a 8-bitor 16-bitdata bus, switchable at reset. [28]
What does MC68000 mean?
To support lower-cost systems and control applications with smaller memory sizes, Motorola introduced the 8-bit compatible MC68008, also in 1982. This is a 68000 with an 8-bit data bus and a smaller (20-bit) address bus. After 1982, Motorola devoted more attention to the 68020and 88000projects.