Question

Write a MIPS assembly program to calculate ⁿC_r.

The program should accept the numbers n and r from the user. The program should call the factorial function.

ⁿC_r = n! / ((n-r)! * r!)

If n<r print an error message "n should not be less than r: re-enter the values." and get the inputs n and r from the user.

Answer 1

        .file   1 ""
        .section .mdebug.abi32
        .previous
        .nan    legacy
        .module fp=32
        .module nooddspreg
        .abicalls
        .rdata
        .align  2
$LC0:
        .ascii  "\012 Enter the value for N and R \000"
        .align  2
$LC1:
        .ascii  "%d%d\000"
        .align  2
$LC2:
        .ascii  "n should not be less than r: re-enter the values\000"
        .align  2
$LC3:
        .ascii  "\012 The value of ncr is: %d\000"
        .text
        .align  2
        .globl  main
        .set    nomips16
        .set    nomicromips
        .ent    main
        .type   main, @function
main:
        .frame  $fp,56,$31              # vars= 16, regs= 4/0, args= 16, gp= 8
        .mask   0xc0030000,-4
        .fmask  0x00000000,0
        .set    noreorder
        .cpload $25
        .set    nomacro
        addiu   $sp,$sp,-56
        sw      $31,52($sp)
        sw      $fp,48($sp)
        sw      $17,44($sp)
        sw      $16,40($sp)
        movz    $31,$31,$0
        move    $fp,$sp
        .cprestore      16
        lw      $2,%got($LC0)($28)
        nop
        addiu   $4,$2,%lo($LC0)
        lw      $2,%call16(puts)($28)
        nop
        move    $25,$2
        .reloc  1f,R_MIPS_JALR,puts
1:      jalr    $25
        nop

        lw      $28,16($fp)
        addiu   $3,$fp,32
        addiu   $2,$fp,28
        move    $6,$3
        move    $5,$2
        lw      $2,%got($LC1)($28)
        nop
        addiu   $4,$2,%lo($LC1)
        lw      $2,%call16(__isoc99_scanf)($28)
        nop
        move    $25,$2
        .reloc  1f,R_MIPS_JALR,__isoc99_scanf
1:      jalr    $25
        nop

        lw      $28,16($fp)
$L5:
        lw      $3,28($fp)
        lw      $2,32($fp)
        nop
        slt     $2,$3,$2
        beq     $2,$0,$L6
        nop

        lw      $2,%got($LC2)($28)
        nop
        addiu   $4,$2,%lo($LC2)
        lw      $2,%call16(printf)($28)
        nop
        move    $25,$2
        .reloc  1f,R_MIPS_JALR,printf
1:      jalr    $25
        nop

        lw      $28,16($fp)
        addiu   $3,$fp,32
        addiu   $2,$fp,28
        move    $6,$3
        move    $5,$2
        lw      $2,%got($LC1)($28)
        nop
        addiu   $4,$2,%lo($LC1)
        lw      $2,%call16(__isoc99_scanf)($28)
        nop
        move    $25,$2
        .reloc  1f,R_MIPS_JALR,__isoc99_scanf
1:      jalr    $25
        nop

        lw      $28,16($fp)
        b       $L5
        nop

$L6:
        nop
        addiu   $3,$fp,32
        addiu   $2,$fp,28
        move    $6,$3
        move    $5,$2
        lw      $2,%got($LC1)($28)
        nop
        addiu   $4,$2,%lo($LC1)
        lw      $2,%call16(__isoc99_scanf)($28)
        nop
        move    $25,$2
        .reloc  1f,R_MIPS_JALR,__isoc99_scanf
1:      jalr    $25
        nop

        lw      $28,16($fp)
        lw      $2,28($fp)
        nop
        move    $4,$2
        lw      $2,%got(fact)($28)
        nop
        move    $25,$2
        .reloc  1f,R_MIPS_JALR,fact
1:      jalr    $25
        nop

        lw      $28,16($fp)
        move    $16,$2
        lw      $2,32($fp)
        nop
        move    $4,$2
        lw      $2,%got(fact)($28)
        nop
        move    $25,$2
        .reloc  1f,R_MIPS_JALR,fact
1:      jalr    $25
        nop

        lw      $28,16($fp)
        move    $17,$2
        lw      $3,28($fp)
        lw      $2,32($fp)
        nop
        subu    $2,$3,$2
        move    $4,$2
        lw      $2,%got(fact)($28)
        nop
        move    $25,$2
        .reloc  1f,R_MIPS_JALR,fact
1:      jalr    $25
        nop

        lw      $28,16($fp)
        mult    $17,$2
        mflo    $2
        nop
        nop
        bne     $2,$0,1f
        div     $0,$16,$2
        break   7
1:
        mfhi    $2
        mflo    $2
        sw      $2,24($fp)
        lw      $5,24($fp)
        lw      $2,%got($LC3)($28)
        nop
        addiu   $4,$2,%lo($LC3)
        lw      $2,%call16(printf)($28)
        nop
        move    $25,$2
        .reloc  1f,R_MIPS_JALR,printf
1:      jalr    $25
        nop

        lw      $28,16($fp)
        nop
        move    $sp,$fp
        lw      $31,52($sp)
        lw      $fp,48($sp)
        lw      $17,44($sp)
        lw      $16,40($sp)
        addiu   $sp,$sp,56
        j       $31
        nop

        .set    macro
        .set    reorder
        .end    main
        .size   main, .-main
        .align  2
        .globl  fact
        .set    nomips16
        .set    nomicromips
        .ent    fact
        .type   fact, @function
fact:
        .frame  $fp,24,$31              # vars= 8, regs= 1/0, args= 0, gp= 8
        .mask   0x40000000,-4
        .fmask  0x00000000,0
        .set    noreorder
        .set    nomacro
        addiu   $sp,$sp,-24
        sw      $fp,20($sp)
        move    $fp,$sp
        sw      $4,24($fp)
        li      $2,1                    # 0x1
        movz    $31,$31,$0
        sw      $2,8($fp)
        lw      $2,24($fp)
        nop
        bne     $2,$0,$L8
        nop

        lw      $2,8($fp)
        b       $L9
        nop

$L8:
        li      $2,1                    # 0x1
        sw      $2,12($fp)
        b       $L10
        nop

$L11:
        lw      $3,8($fp)
        lw      $2,12($fp)
        nop
        mult    $3,$2
        mflo    $2
        sw      $2,8($fp)
        lw      $2,12($fp)
        nop
        addiu   $2,$2,1
        sw      $2,12($fp)
$L10:
        lw      $3,12($fp)
        lw      $2,24($fp)
        nop
        slt     $2,$2,$3
        beq     $2,$0,$L11
        nop

        lw      $2,8($fp)
$L9:
        move    $sp,$fp
        lw      $fp,20($sp)
        addiu   $sp,$sp,24
        j       $31
        nop

        .set    macro
        .set    reorder
        .end    fact
        .size   fact, .-fact
        .ident  "GCC: (Ubuntu 5.4.0-6ubuntu1~16.04.9) 5.4.0 20160609"