This program should print out a pattern with dollar signs$($$$,$ ascii hex code $0$x$24)$ and character $\text{'}0\text{'}($ascii hex $0$x$30)$ and the newline character $$

$($ascii hex code $0$x$0$a$).$

$1.$ It will first prompt for the height of the pattern $($i$.$e$.,$ the number of rows in the pattern$).$ If the user enters an invalid input such as a negative number or zero, an error message will be printed and the user will be prompted again. These error messages are listed in the starter code in the Lab$3.$asm file provided.

$2.$ Then your program should generate the following pattern, a $"$ right$-$angled triangle", using the

aforementioned characters. Refer to test cases in testCases sub folder in Lab$3$ folder for examples.

$3.$ This entire pattern generated from the user input of n is written to the file lab$3\_$output.txt$.$

$****************************************************************************************$

Below is the Lab$3.$asm code that was provided with the problem statement. Please write the code that needs to be added to the part which is left blank and has to be written after the comments #$................$ your code starts here..........................................................#$.$

Please help. Thanks

$*************************************************************$

Lab$3.$asm

$.$macro exit #macro to exit program

li a$7,10$

ecall

$.$end$\_$macro

$.$macro print$\_$str$(\%$string$1)$ #macro to print any string

li a$7,4$

la a$0,\%$string$1$

ecall

$.$end$\_$macro

$.$macro read$\_$n$(\%$x$)$#macro to input integer n into register x

li a$7,5$

ecall

#a$0$ now contains user input

addi $\%$x$,$ a$0,0$

$.$end$\_$macro

$.$macro print$\_$n$(\%$x$)$#macro to input integer n into register x

addi a$0,\%$x$,0$

li a$7,1$

ecall

$.$end$\_$macro

$.$macro file$\_$open$\_$for$\_$write$\_$append$(\%$str$)$

la a$0,\%$str

li a$1,1$

li a$7,1024$

ecall

$.$end$\_$macro

$.$macro initialise$\_$buffer$\_$counter

#buffer begins at location $0$x$10040000$

#location $0$x$10040000$ to keep track of which address we store each character byte to

#actual buffer to store the characters begins at $0$x$10040008$

#initialize mem$[0$x$10040000]$ to $0$x$10040008$

addi sp$,$ sp$,-16$

sd t$0,0($sp$)$

sd t$1,8($sp$)$

li t$0,0$x$10040000$

li t$1,0$x$10040008$

sd t$1,0($t$0)$

ld t$0,0($sp$)$

ld t$1,8($sp$)$

addi sp$,$ sp$,16$

$.$end$\_$macro

$.$macro write$\_$to$\_$buffer$(\%$char$)$

#NOTE:this macro can add ONLY $1$ character byte at a time to the file buffer!

addi sp$,$ sp$,-16$

sd t$0,0($sp$)$

sd t$4,8($sp$)$

li t$0,0$x$10040000$

ld t$4,0($t$0)$#t$4$ is starting address

#t$4$ now points to location where we store the current $\%$char byte

#store character to file buffer

li t$0,\%$char

sb t$0,0($t$4)$

#update address location for next character to be stored in file buffer

li t$0,0$x$10040000$

addi t$4,$ t$4,1$

sd t$4,0($t$0)$

ld t$0,0($sp$)$

ld t$4,8($sp$)$

addi sp$,$ sp$,16$

$.$end$\_$macro

$.$macro fileRead$(\%$file$\_$descriptor$\_$register, $\%$file$\_$buffer$\_$address$)$

#macro reads upto first $10,000$ characters from file

addi a$0,\%$file$\_$descriptor$\_$register, $0$

li a$1,\%$file$\_$buffer$\_$address

li a$2,10000$

li a$7,63$

ecall

$.$end$\_$macro

$.$macro fileWrite$(\%$file$\_$descriptor$\_$register, $\%$file$\_$buffer$\_$address,$\%$file$\_$buffer$\_$address$\_$pointer$)$

#macro writes contents of file buffer to file

addi a$0,\%$file$\_$descriptor$\_$register, $0$

li a$1,\%$file$\_$buffer$\_$address

li a$7,64$

#a$2$ needs to contains number of bytes sent to file

li a$2,\%$file$\_$buffer$\_$address$\_$pointer

ld a$2,0($a$2)$

sub a$2,$ a$2,$ a$1$

ecall

$.$end$\_$macro

$.$macro print$\_$file$\_$contents$(\%$ptr$\_$register$)$

li a$7,4$

addi a$0,\%$ptr$\_$register, $0$

ecall

#entire file content is essentially stored as a string

$.$end$\_$macro

$.$macro close$\_$file$(\%$file$\_$descriptor$\_$register$)$

li a$7,57$

addi a$0,\%$file$\_$descriptor$\_$register, $0$

ecall

$.$end$\_$macro

$.$data

prompt: $.$asciz "Enter the height of the pattern $($must be greater than $0)$:$"$

invalidMsg: $.$asciz "Invalid Entry!"

newLine: $.$asciz $"$

$"$

star$\_$dollar: $.$asciz $"*$$$"$

dollar: $.$asciz $"$$$"$

star: $.$asciz $"*"$

blankspace: $.$asciz $""$

outputMsg: $.$asciz $"$ display pattern saved to lab$3\_$output.txt $"$

filename: $.$asciz "lab$3\_$output.txt$"$

Zero:.asciz"$0"$

$.$text

file$\_$open$\_$for$\_$write$\_$append$($filename$)$

#a$0$ now contaimns the file descriptor $($i$.$e$.$ ID no$.)$

#save to t$6$ register

addi t$6,$ a$0,0$

initialise$\_$buffer$\_$counter

#for utilsing macro write$\_$to$\_$buffer, here are tips:

#$0$x$2$a is the ASCI code input for star$(*)$

#$0$x$24$ is the ASCI code input for dollar$($$$)$

#$0$x$30$ is the ASCI code input for the character $\text{'}0\text{'}$

#$0$x$0$a is the ASCI code input for newLine $(/$n$)$

#START WRITING YOUR CODE FROM THIS LINE ONWARDS

#DO NOT use the registers a$0,$ a$1,$ a$7,$ t$6,$ sp anywhere in your code.

#$................$ your code starts here..........................................................#

#$................$ your code ends here..........................................................#

#END YOUR CODE ABOVE THIS COMMENT

#Don't change anything below this comment!

Exit:

#write null character to end of file

write$\_$to$\_$buffer$(0$x$00)$