Question

8. A RISC machine has 186 total registers of which 18 are global. There are 12 register windows and each window has 10 local registers. (See Figure 15.2 p. 544 as an example). How many input and output registers are in each window? Show your work.

Answer 1

Risc processor supports high number of registers .

These registers are classified into 4 types

Global registers [G]

Local registers [L]

In registers [C] and out register [C] . In and Out registers are also known as common registers . Global registers are accessible to all the Register Windows . Therefore number of register present in windows are calculated as

Window Size = L + 2*C + G

In the RISC CPU registers are organized in an overlap windows or in other words One Window Out Register[C] is used as an In Register in another window

so we can weite

number of Registers in CPU (OR) Register File size = W( L + C) + G

where W represents the number of windows in CPU