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Answer:

The big end is the byte that contains 0x00.

Notice that "big end" refers to position within the word, not the value of the byte.


Byte Order of MIPS and SPIM

Within a byte, for all processors, bit 7 is the most significant bit. So the big end byte looks the same for both byte orderings. Usually in printed material this bit is shown at the left, as in 00010010. Note: except when discussing byte ordering, the "big end" byte is called the "high-order byte" or the "most significant byte".

The MIPS processor chip can be set up in hardware to use either byte ordering. A computer system designer makes whatever choice best fits the rest of the components in the computer system. The SPIM simulator uses the byte ordering of the computer it is running on.

The examples in these notes were done on a Windows/Intel computer. If you are using a Macintosh there will be occasional differences.


QUESTION 4:

Here is a bit pattern, with the most significant bits written on the left (as is usual in print): 0xFF00AA11. Copy the bytes to memory using big endian and little endian orders:

Little Endian
AddressContents
4003
4002
4001
4000
Big Endian
AddressContents
4003
4002
4001
4000