Question

Please write MIPS program that runs in QtSpim (ex: MipsFile.s)

Write a MIPS program that will read in a base (as an integer) and a value (nonnegative integer but as an ASCII string) in that base and print out the decimal value; you must implement a function (which accepts a base and an address for a string as parameters, and returns the value) and call the function from the main program. The base will be given in decimal and will be between 2 and 36, and the digits for the values will be in set [0…9, a…z]. You can assume that no overflow will occur and the value is valid in the given base.

An example run will be:

Enter a base (between 2 and 36 in decimal): 2

Enter a number in base 2: 101

The value in decimal is: 5

The program needs to be able to test 3 different cases and run in QtSpim like a .s file

here is a c program that shows the functionality

#include <ctype.h>
#include <stdio.h>
#include <string.h>
int convert2dec(char *str, int base) 
{
  int j, val;
  val = 0;
  j = 0;
  while (str[j] > 13) {
    if (str[j] > 57) 
      val = val * base + str[j]-87;
    else
      val = val * base + str[j] - 48;
    j++;
  }
  return val;
}
 
int main(int argc, char *argv[])
{
  int X;
  char str[256];
  printf("Please the base (in decimal): ");
  scanf("%d", &X);
  printf("Please enter a nonnegative number: ");
  scanf("%s", str);
  printf("The decimal value is %d.\n", convert2dec(str,X));
  return 0;
}

Answer 1

Answer:

MIPS Assembly Language Program :

convert2dec(char*, int):
        push    rbp
        mov     rbp, rsp
        mov     QWORD PTR [rbp-24], rdi
        mov     DWORD PTR [rbp-28], esi
        mov     DWORD PTR [rbp-8], 0
        mov     DWORD PTR [rbp-4], 0
.L5:
        mov     eax, DWORD PTR [rbp-4]
        movsx   rdx, eax
        mov     rax, QWORD PTR [rbp-24]
        add     rax, rdx
        movzx   eax, BYTE PTR [rax]
        cmp     al, 13
        jle     .L2
        mov     eax, DWORD PTR [rbp-4]
        movsx   rdx, eax
        mov     rax, QWORD PTR [rbp-24]
        add     rax, rdx
        movzx   eax, BYTE PTR [rax]
        cmp     al, 57
        jle     .L3
        mov     eax, DWORD PTR [rbp-8]
        imul    eax, DWORD PTR [rbp-28]
        mov     edx, eax
        mov     eax, DWORD PTR [rbp-4]
        movsx   rcx, eax
        mov     rax, QWORD PTR [rbp-24]
        add     rax, rcx
        movzx   eax, BYTE PTR [rax]
        movsx   eax, al
        add     eax, edx
        sub     eax, 87
        mov     DWORD PTR [rbp-8], eax
        jmp     .L4
.L3:
        mov     eax, DWORD PTR [rbp-8]
        imul    eax, DWORD PTR [rbp-28]
        mov     edx, eax
        mov     eax, DWORD PTR [rbp-4]
        movsx   rcx, eax
        mov     rax, QWORD PTR [rbp-24]
        add     rax, rcx
        movzx   eax, BYTE PTR [rax]
        movsx   eax, al
        add     eax, edx
        sub     eax, 48
        mov     DWORD PTR [rbp-8], eax
.L4:
        add     DWORD PTR [rbp-4], 1
        jmp     .L5
.L2:
        mov     eax, DWORD PTR [rbp-8]
        pop     rbp
        ret
.LC0:
        .string "Please the base (in decimal): "
.LC1:
        .string "%d"
.LC2:
        .string "Please enter a nonnegative number: "
.LC3:
        .string "%s"
.LC4:
        .string "The decimal value is %d.\n"
main:
        push    rbp
        mov     rbp, rsp
        sub     rsp, 288
        mov     DWORD PTR [rbp-276], edi
        mov     QWORD PTR [rbp-288], rsi
        mov     edi, OFFSET FLAT:.LC0
        mov     eax, 0
        call    printf
        lea     rax, [rbp-4]
        mov     rsi, rax
        mov     edi, OFFSET FLAT:.LC1
        mov     eax, 0
        call    scanf
        mov     edi, OFFSET FLAT:.LC2
        mov     eax, 0
        call    printf
        lea     rax, [rbp-272]
        mov     rsi, rax
        mov     edi, OFFSET FLAT:.LC3
        mov     eax, 0
        call    scanf
        mov     edx, DWORD PTR [rbp-4]
        lea     rax, [rbp-272]
        mov     esi, edx
        mov     rdi, rax
        call    convert2dec(char*, int)
        mov     esi, eax
        mov     edi, OFFSET FLAT:.LC4
        mov     eax, 0
        call    printf
        mov     eax, 0
        leave
        ret