Question

1.  Write an input-output utility io_lib.asm that contains the following subprograms:

     a.  input_sub:  get user input

          - prompt the user to enter an integer

          - print the entered input as hexadecimal in the format of:  0xnnnnnnnn

 

     b.  output_sub:  print output

          - print a text string provided by the caller

          - print the value in hexadecimal format

 

2.  Write a logic operation utility logic_lib.asm that contains the following subprograms:

     a.  nor_sub:  take two input parameters, and return the NOR operation on those two parameter.

     b. nand_sub:  take two input parameters, and return the NAND operation on those two parameter.

     c. not_sub:  take one input parameters, and return the NOT operation on that parameter.

     d. mult4_sub:  take an input parameter, and return that parameter multiplied by 4 using only shift and add operations.

     e. mult10_sub:  take an input parameter, and return that parameter multiplied by 10 using only shift and add operations.

     f. cir_sh_r_sub:  take an input parameter as value to shift and a second parameter as the shift amount, and return the shifted value     

     g. cir_sh_l_sub:  take an input parameter as value to shift and a second parameter as shift amount, and return the shifted value

 

3.  Write the main program that does the followings by calling supprograms in io_lib.asm and logic_lib.asm:

 

     a.  Prompt user for 2 input integers:  A and B

 

     b.  Display A and B in hexadecimal format

 

     c.  Display A NOR B

 

     d.  Display A NAND B

 

     e.  Display NOT(A)

 

     f.  Display (A*4) and (B*10)

 

     f.   Show A Right Circular Shift by entered number of bits

 

    g.  Show B Left Circular Shift by entered number of bits

 

 

Sample output:

 

Enter value for A:  5

Hex value of 5 is:  0x05

Enter shift amount for A:  3

 

Enter value for B:  8

Hex value of 8 is:  0x08

Enter shift amount for B:  4

 

A NOR B = 0xFFFFFFF2

A NAND B = 0xFFFFFFF

NOT(A) = 0xFFFFFFFA

A * 4 = 20

B * 10 = 80

 

A circular shifted R by 3 = 0xA0000000

B circular shifted L by 4 = 0x00000080

Answer 1

1.Write an input-output utility io_lib.asm that contains the following:

# Read integer A from user and store it into a register

# Display the integer in binary

# Display the integer in Hex

# set Register $a0 to contain only bits 12,13,14,15 of $a0

# Display the integer in binary contained in $a0

# Display the integer in hex contained in $a0

.data

userInput: .asciiz "Please enter your integer: "

binaryInput: .asciiz "Here is the input in binary: "

nl: .asciiz "\n"

hexInput: .asciiz "Here is the input in hexadecimal: "

binaryOutput: .asciiz "Here is the output in binary: "

hexOutput: .asciiz "Here is the output in hexadecimal: "

hexDigit: .asciiz "0123456789ABCDEF"

obuf: .space 100

obufe:

.text

.globl main

main:

# ask end-user to submit an integer value

li $v0,4

la $a0,userInput

syscall

# read user-input

li $v0,5

syscall

move $s0,$v0

# output original in binary

la $a0,binaryInput

li $a1,32

jal prtbin

# output original in hex

la $a0,hexInput

li $a1,32

jal prthex

# isolate bits 12,13,14,15

srl $s0,$s0,12

andi $s0,$s0,0x0F

# output isolated in binary

la $a0,binaryOutput

li $a1,4

jal prtbin

# output isolated in hex

la $a0,hexOutput

li $a1,4

jal prthex

# exit the program

li $v0,10

syscall

# prtbin -- print in binary

#

# arguments:

# a0 -- output string

# a1 -- number of bits to output

prtbin:

li $a2,1 # bit width of number base digit

j prtany

# prthex -- print in binary

#

# arguments:

# a0 -- output string

# a1 -- number of bits to output

prthex:

li $a2,4 # bit width of number base digit

j prtany

# prtany -- print in given number base

#

# arguments:

# a0 -- output string

# a1 -- number of bits to output

# a2 -- bit width of number base digit

# s0 -- number to print

#

# registers:

# t0 -- current digit value

# t5 -- current remaining number value

# t6 -- output pointer

# t7 -- mask for digit

prtany:

li $t7,1

sllv $t7,$t7,$a2 # get mask + 1

subu $t7,$t7,1 # get mask for digit

la $t6,obufe # point one past end of buffer

subu $t6,$t6,1 # point to last char in buffer

sb $zero,0($t6) # store string EOS

move $t5,$s0 # get number

prtany_loop:

and $t0,$t5,$t7 # isolate digit

lb $t0,hexDigit($t0) # get ascii digit

subu $t6,$t6,1 # move output pointer one left

sb $t0,0($t6) # store into output buffer

srlv $t5,$t5,$a2 # slide next number digit into lower bits

sub $a1,$a1,$a2 # bump down remaining bit count

bgtz $a1,prtany_loop # more to do? if yes, loop

# output string

li $v0,4

syscall

# output the number

move $a0,$t6 # point to ascii digit string start

syscall

# output newline

la $a0,nl

syscall

jr $ra # return