Big-endian processors, also known as "big-endian order" or "big-endian byte order" are a particular data order used to store data in memory, especially multi-byte data such as integers and floating-point numbers. This document will explain how these processors work and their differences for Motorola and MM processors.
What is big-endian byte ordering?
Big-endian byte-ordering is a type of byte-ordering that stores data in memory such that the most significant byte (MSB) is stored in the smallest memory address and the least-significant byte (LSB) is stored in the largest memory address. This is the opposite of little-endian byte order, which stores data such that the least significant byte is stored in the smallest memory address.
What is special about big-endian processors?
Big-endian processors have special instructions to facilitate the endianness conversion when accessing memory. By contrast, little-endian processors either do not need those instructions or provide them as an optional feature. In this way, big-endian processors can more easily support different types of data and operations.
Differences between Motorola and MM big-endian processors
The most dominant big-endian processor architectures are Motorola 68000 series and the MIPS family. Both of these architectures provide special instructions for big-endian data access.
The main difference between the two is that Motorola 68000 series processors can handle both 16- and 32-bit data whereas MIPS family processors only support 32-bit data. Additionally, MIPS family processors use REV (reverse) instructions while Motorola 68000 series processor use BSWAP (byte swap) instructions.
FAQs
What is big-endian byte ordering?
Big-endian byte-ordering is a type of byte-ordering that stores data in memory such that the most significant byte (MSB) is stored in the smallest memory address and the least-significant byte (LSB) is stored in the largest memory address.
What is special about big-endian processors?
Big-endian processors have special instructions to facilitate the endianness conversion when accessing memory. By contrast, little-endian processors either do not need those instructions or provide them as an optional feature.
What are the most prominent big-endian processor architectures?
The most dominant big-endian processor architectures are Motorola 68000 series and the MIPS family.
What is the main difference between Motorola and MIPS big-endian processors?
The main difference between the two is that Motorola 68000 series processors can handle both 16- and 32-bit data whereas MIPS family processors only support 32-bit data. Additionally, MIPS family processors use REV (reverse) instructions while Motorola 68000 series processor use BSWAP (byte swap) instructions.
What instructions do big-endian processors support?
Big-endian processors support special instructions such as BSWAP (byte swap) for Motorola 68000 series processors and REV (reverse) for MIPS family processors that facilitate the endianness conversion when accessing memory.