What is a 32-Bit Long Instruction?

[Blake Barker]

1) Each instruction is composed (made) of a number of binary digits which are often called bits. Bits is short for Binary digits

a.       An instruction like “add 2 numbers” is represented in the computer by a code/number that exists somewhere else in the processor—a code the computer recognizes.  The computer interprets this number/code as a particular job to do.

b. The number that tells the computer to do a specific job is represented not with a base-10 (decimal) number.  The number that tells the computer to do a specific job is represented with a base-2 (binary) number.

i. The base-10, or decimal number, can be made-up of the digits 0 through 9.  Notice this is in fact 10 digits.  It is not native to computer’s inherent logic.

ii. The base-2, or binary number, can be made up of the digits 0 through 1.  Notice that this in fact is 2 digits.  It is native to the computer’s inherent.

iii. The base-16, or hexadecimal number, can be made up of the characters 0 through 9 including A through F.  It is native to the computer’s inherent logic

iv. This is easier…

c. A “bit” is short for binary digit.  A bit, or binary digit is a 0 or 1; many times thought of as “off” or “on,” “true” or “false…”  Something you might know is that a bit and a “byte” seem like they belong to computers.  Yip.  A byte is made of 8 bits.  “Bytes break into 8 bits” is one way to remember it. Sometime in the past, half a byte (4 bits) was called a “nibble.”

d. The code/number representing the instruction the computer should perform can be represented by some number of bits.  Since I’m an old-time IBM-PC programmer, at that time an instruction was represented by some number/code by a byte—the combination.

i.  Remembering…  I’m sure there are not nearly as many instructions for the old 8088/8086 processors as can be represented by a byte.  A byte can represent up to 256 (0 through 256) with its 8 bits, and certainly there weren’t that many instructions used nor needed for a 16-bit architecture.  (Don’t take my word for it.)

ii.      Tricky glue:  a bit is represented by a small letter b.  A byte is represented by a large letter B.  A broadband download speed of 10 Mbps is 8 times slower than 10 MBps!!

MIPS architecture has instructions that are 32 bits long. Translation: 32 binary digits long.