5. The integer-to-string program presented in Section 4.5 converts an unsigned i

Question

5. The integer-to-string program presented in Section 4.5 converts an unsigned integer to string format using successive division by 10 and storing the remainder digit characters in a string. It is also possible to convert the unsigned integer to any radix using successive divisions by the radix value. Rewrite the integer-to-string program asking the user to input an unsigned integer and a radix value between 2 and 10. Do the radix conversion and then print the string. Make sure that the string has sufficient space characters, especially when converting to radix using mips languge

Explanation / Answer

#IO #Prompts user to input 10 ascii digits into an array #Converts the string of digits into a single int #Also handles any number of digits between 1 and 10 #Returns 0 if non-digit chars are entered into the string .data #declaration of vars follows array: .space 11 #reserves space for a 10 elem array char: .space 2 prompt: .asciiz "Please enter 10 numbers, then press ENTER: " null: .asciiz "" space: .ascii " " newline: .asciiz " " .text #instructions follow main: la $a0, prompt #load prompt message into $a0 for syscall li $v0, 4 #load syscall to print string syscall #print prompt message j readInt #call readInt function to get user input string gets: #read multiple chars from keyboard buffer until ENTER key, #add NULL char and store into buffer pointed to by *array #passed to the subroutine la $s1, array #set base address of array to s1 loop: #start of read loop jal getc #jump to getc subroutine lb $t0, char #load the char from char buffer into t0, stripping null sb $t0, 0($s1) #store the char into the nth elem of array lb $t1, newline #load newline char into t1 beq $t0, $t1, done #end of string? jump to done addi $s1, $s1, 1 #increments base address of array j loop #jump to start of read loop getc: #read char from keyboard buffer and return ascii value li $v0, 8 #call code for read string la $a0, char #load address of char for read li $a1, 2 #length of string is 1byte char and 1byte for null syscall #store the char byte from input buffer into char jr $ra #jump-register to calling function readInt: #read string of ascii digits, store into a local variable and #convert into integer, return that int unless string contains #non-integers j gets #let s1 be top address of array, let s0 be the digitcounter done: #let s2 be the sum total addi $s1, $s1, -1 #reposition array pointer to last char before newline char la $s0, array #set base address of array to s0 for use as counter addi $s0, $s0, -1 #reposition base array to read leftmost char in string add $s2, $zero, $zero #initialize sum to 0 li $t0, 10 #set t0 to be 10, used for decimal conversion li $t3, 1 lb $t1, 0($s1) #load char from array into t1 blt $t1, 48, error #check if char is not a digit (ascii'9') addi $t1, $t1, -48 #converts t1's ascii value to dec value add $s2, $s2, $t1 #add dec value of t1 to sumtotal addi $s1, $s1, -1 #decrement array address lp: #loop for all digits preceeding the LSB mul $t3, $t3, $t0 #multiply power by 10 beq $s1, $s0, FIN #exit if beginning of string is reached lb $t1, ($s1) #load char from array into t1 blt $t1, 48, error #check if char is not a digit (ascii'9') addi $t1, $t1, -48 #converts t1's ascii value to dec value mul $t1, $t1, $t3 #t1*10^(counter) add $s2, $s2, $t1 #sumtotal=sumtotal+t1 addi $s1, $s1, -1 #decrement array address j lp #jump to start of loop error: #if non digit chars are entered, readInt returns 0 add $s2, $zero, $zero j FIN FIN: li $v0, 1 add $a0, $s2, $zero syscall li $v0, 10

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