a) What will be the logic levels on the external SRC buseswhen each of the given

Question

a) What will be the logic levels on the external SRC buseswhen each of the given SRC instruction is executing on theprocessor? Complete Table: A all numbers are in the decimal numbersystem, unless noted otherwise. (Assume the required missinginformation if necessary)

b) Specify memory addressing modes for each of theSRC instructions given in Table.

SRC

instruction

RTL Equivalent

Address

Bus<31….0>

Data Bus

<31….0>

MRead

MWrite

Ld

r3,12(r5)

Ld r2,16

Table A

Assumptions:

• All memory content is aligned properly.

• In other words, all the memory accesses start ataddresses divisible by 4.

• Value in the PC = 000DC348h

Memory map with assumed values

Memory Address

Memory Content

…………

…..

00000020h

D2h

000DC340h

51h

00000021h

96h

000DC341h

CAh

00000022h

49h

000DC343h

D5h

00000023h

2Fh

000DC344h

E2h

………

….

………

……

000DC300h

44h

00AB1240h

O7h

000DC301h

23h

00AB1241h

85h

000DC302h

E3h

00AB1242h

E5h

000DC303h

D5h

00AB1243h

3Dh

Fig. 3

Register map with assumed values

Register Name

Content

R[0]

0012A54Bh

R[1]

10234CB8h

R[2]

D296492Fh

R[3]

001400CDh

R[4]

B7432301h

R[5]

00AB1234h

R[6]

00000020h

R[7]

01432D7Fh

R[8]

00B94821h

R[9]

00CDA7A3h

R[10]

0031A0F0h

R[11]

0012A246h

R[12]

000FAB17h

Fig. 4

SRC

instruction

RTL Equivalent

Address

Bus<31….0>

Data Bus

<31….0>

MRead

MWrite

Ld

r3,12(r5)

Ld r2,16

Explanation / Answer

SRC Instruction

RTL Equilent

Address bus<31 0>

Data bus

<31   0>

M(R)

M(W)

LD r3,12(r5)

R[3]<-M[12+R[5]

00AB1240h

0785E530h

1

0

LD r2,16

R[2]<-M[16]

00000020h

D296492fh

1

0

(b) Specify memory addressing modes for each of the SRCinstructions given in Table.

Solution:-

Memory Addressing

SRC Instruction

LD r7,12(r5)

LD r2,16

Addressing Mode

Displacement

Direct

SRC Instruction

RTL Equilent

Address bus<31 0>

Data bus

<31   0>

M(R)

M(W)

LD r3,12(r5)

R[3]<-M[12+R[5]

00AB1240h

0785E530h

1

0

LD r2,16

R[2]<-M[16]

00000020h

D296492fh

1

0

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