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Chapter One: Computer architecture
Step 1: Understand the components of the simulator (in this case, use open-source
tool called Johnny simulator as shown in Figure 1.1. Terminologies used
for simulator operations are indicated in Table 1.1.

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Input

Input

Figure 1.1: Components of Johnny simulator

Table 1.1: Description of the terms and operations used in the simulators
S/N Command/term Description
Memory ram->db Data from the addressed location in the RAM can
(RAM) be transferred onto the data bus
db->ram Data from the data bus can be transferred onto the
addressed location in the RAM.
The Control db->ins The content of the data bus is transferred to the
Unit instruction register.
ins- >ab The content of the instruction register is transferred
to the data bus.
ins->pc The content of the instruction register is transferred
to the program counter
pc->ab The content of the program counter is transferred
to the address bus
ins->mc The content of the instruction register is transferred
to the micro instruction counter
stopp The simulator shows a message that the program
execution is finished.

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Student’s Book Form Five

Computer Science Form 5.indd 3 23/07/2024 12:32