# RISC$-$V Assembly Code for Diamond Pattern

$.$data

prompt: $.$asciiz "Enter a positive odd integer $($N$)$: $"$

newline: $.$asciiz $"$

$"$

$.$text

main:

# Prompt user for input

li a$1,1$ # file descriptor $($stdout$)$

li a$2,$ prompt # pointer to the string

li a$3,39$ # string length

li a$7,64$ # system call code for write

ecall

# Read user input

li a$0,0$ # file descriptor $($stdin$)$

li a$2,10$ # buffer size

li a$7,8$ # system call code for read

ecall

# Convert string to integer $($you$\text{'}$ll need a conversion subroutine$)$

# $($This part is missing and requires a separate subroutine$)$

# Check if N is odd, adjust if necessary

# $($You need to check the least significant bit to ensure it's odd$)$

# Initialize loop counters

li t$0,1$ # Loop counter for rows

draw$\_$diamond:

# Draw the upper part of the diamond

beqz t$0,$ draw$\_$lower$\_$diamond # Exit loop if upper part is done

# Calculate number of asterisks for the current row

li t$1,2$ # Number of asterisks for the first row

mul t$1,$ t$1,$ t$0$ # Multiply by the current row number

sub t$1,$ t$1,1$ # Subtract $1$ to get odd numbers

# Print asterisks for the current row

li a$1,1$ # file descriptor $($stdout$)$

li a$2,\text{'}*\text{'}$ # character to print

li a$3,1$ # string length

li a$7,64$ # system call code for write

# Loop to print asterisks

la t$2,$ newline # Load newline character address

print$\_$asterisks:

ecall # Print asterisk

add t$1,$ t$1,-1$ # Decrement asterisk count

bnez t$1,$ print$\_$asterisks # Loop until all asterisks are printed

# Move to the next row

la t$2,$ newline # Load newline character address

ecall # Print newline

add t$0,$ t$0,1$ # Increment row counter

j draw$\_$diamond # Jump back to draw$\_$diamond loop

draw$\_$lower$\_$diamond:

# Draw the lower part of the diamond

# $($This part is similar to the upper part with a reversed loop$)$

# Exit the program

li a$7,10$ # system call code for exit

li a$0,0$ # exit status

ecall