2.2(lecture)2.5-Representing Instructions in the Computer
all MIPS instructions are ___ bits long
32
instruction format
A form of representation of an instruction composed of fi elds of binary numbers. -the rectangle with decimal reps in it, seperated feilds
op
Basic operation of the instruction, traditionally called the opcode.
machine language
Binary representation used for communication within a computer system
When instructions need to be larger then 32 bits, as they often do, this leads us to the fi nal hardware design principle:
Good design demands good compromises.
Itype
Immediate op,rs,rt,constant or address used for immediate data transfer instructions
shamt:
Shift amount
rs
Th e fi rst register source operand
rd
Th e register destination operand. It gets the result of the operation.
rt
Th e second register source operand.
■ funct
Th is fi eld, oft en called the function code, selects the specifi c variant of the operation in the op fi eld.
Th e compromise chosen by the MIPS designers is to keep all instructions the same length, thereby requiring _____
diff erent kinds of instruction formats for diff erent kinds of instructions
the formats are distinguished by the values in the ____,each format is assigned a distinct set of values in the fi rst fi eld (op) so that the hardware knows whether to treat the last half of the instruction as three fi elds (R-type) or as a single fi eld (I-type)
fi rst fi eld
Instructions are kept in the computer as a series of _____ electronic signals and may be represented as numbers
high and low
each piece of an instruction can be considered as an individual number, and placing these numbers side by side forms the ____.
instruction
What are the MIPS fields
op,rs,rt,rd,shamt,funct
A ____- occurs when an instruction needs longer fi elds than those shown above.
problem
R-type
register op,rs,rt,rd,shamt,funct
In MIPS assembly language, registers $s0 to $s7 map to____-
registers 16 to 23
In MIPS assembly language, registers $t0 to $t7 map onto
registers 8 to 15
machine code
sequence of machine langauge instruction