What value in the KBSR means that new data is available for input from the keyboard?

a$.$ KBSR $=1$

b$.$ KBDR$[15]=1$

c$.$ KBSR$[15]=1$

d$.$ KBSR$[14]=0$

e$.$ KBSR$[14]=1$

$14.$ What value is sent to the DR of the Register File when executing the TRAP instruction?

a$.$ b$111$ b$.$ b$101$ c$.$ b$011$

d$.$ The value stored in the trapvec$8$ part of the TRAP instruction format

e$.$ None of the options

$15.$ One control signal selects ZEXT$($IR$[7$:$0])$ in the MARMUX. Which of the following instructions would

use this control signal?

a$.$ NOT

b$.$ LD$,$ LDI, & LDR

c$.$ ST$,$ STI, & STR

d$.$ BR & JM

e$.$ TRAP

Instruction Formats

The next two questions refer to the following system:

A certain ISA has a $24-$bit word size, uses single word $(24-$bit$)$ instructions, has $32$ opcodes, $64$ registers,

and $256$ M of byte$-$addressable memory. One group of instructions in this ISA takes the form:

OPCODE $|$ DESTINATION REGISTER $|$ SOURCE REG. $|$ Flag $|$ IMMEDIATE VALUE

Or

OPCODE $|$ DESTINATION REGISTER $|$ SOURCE REG. $1|$ Flag $|$ SOURCE REG. $2$

A single bit in the instruction $("$Flag$")$ is used to differentiate these two addressing modes.

Another group of instructions takes the form

OPCODE $|$ SOURCE$/$DESTINATION REGISTER $|$ PC OFFSET

$4$