$.$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$00)$

#write file buffer to file

fileWrite$($t$6,0$x$10040008,0$x$10040000)$

addi t$5,$ a$0,0$

print$\_$str$($newLine$)$

print$\_$str$($outputMsg$)$

exit