需要给定正向订单代码的反向订单代码

Question

我需要使用以相反顺序添加的 Nilakantha 级数的前 k 项来计算 pi（单精度）的值。我有远期订单的代码，如下所示。现在有人可以帮助我开始如何进行相反的顺序吗？

    li $t1, 0           # constant value of 0
    mtc1 $t1, $f0       # $f0 = current sum
    cvt.s.w $f0, $f0    # convert representation from 2's complement to IEEE float (not needed for 0)

    li $t1, 2           
    mtc1 $t1, $f2       # $f2 = constant value of 2
    cvt.s.w $f2, $f2    # convert representation of 2 to float

    li $t1, 3           
    mtc1 $t1, $f4       # $f6 = constant value of 3
    cvt.s.w $f4, $f4    # convert representation of 3 to float

    li $t1, 4           
    mtc1 $t1, $f6       # $f6 = constant value of 4
    cvt.s.w $f6, $f6    # convert representation of 4 to float

    li $t1, 0           
    mtc1 $t1, $f8       # $f8 = current numerator
    cvt.s.w $f8, $f8    # convert representation to float

    li $t1, 0           
    mtc1 $t1, $f10       # $f10 = current denominator
    cvt.s.w $f10, $f10   # convert representation to float

    li $t1, 0           
    mtc1 $t1, $f12       # $f12 = first fraction of denomintor
    cvt.s.w $f12, $f12   # convert representation to float

    li $t1, 0           
    mtc1 $t1, $f14      # $f14 = second fraction of denomintor
    cvt.s.w $f14, $f14   # convert representation to float

    li $t1, 0           
    mtc1 $t1, $f16       # $f16 = thridt fraction of denomintor
    cvt.s.w $f16, $f16   # convert representation to float

    li $t1, 0           
    mtc1 $t1, $f18        # $f18 = n
    cvt.s.w $f18, $f18    # convert representation to float

    li $t1, 1           
    mtc1 $t1, $f20        # $f12 = constant value of 1
    cvt.s.w $f20, $f20    # convert representation to float

    li $t1, -1           
    mtc1 $t1, $f22        # $f22 = constant value of -1
    cvt.s.w $f22, $f22    # convert representation to flaot

single_forward:
    mov.s $f24, $f18
    cvt.w.s $f24, $f24
    mfc1 $t2, $f24
    andi $t3, $t2, 1
    bnez $t3, odd

even:
    mul.s $f8, $f20, $f6        # current numerator when n is even
    
    mul.s $f30, $f2, $f18       # $f30 = 2n
    add.s $f12, $f30, $f2       # $f12 = (2n+2)
    add.s $f14, $f12, $f20      # $f14 = (2n+3)
    add.s $f16, $f14, $f20      # $f16 = (2n+4)
    mul.s $f10, $f12, $f14      # current denominator (2n+2)(2n+4)
    mul.s $f10, $f10, $f16      # $f10 = (2n+2)(2n+3)(2n+4)

    div.s $f24, $f8, $f10       # $f24 = result
    add.s $f0, $f0, $f24        # update the sum

    add.s $f18, $f18, $f20      # increment n counter
    mov.s $f24, $f18            # f24 = current n count
    cvt.w.s $f24, $f24          # convert representation to float
    mfc1 $t4, $f24              # 
    beq $a0, $t4, done

    j single_forward
    
odd:
    mul.s $f8, $f22, $f6       # current numerator when n is odd

    mul.s $f30, $f2, $f18       # $f30 = 2n
    add.s $f12, $f30, $f2       # $f12 = (2n+2)
    add.s $f14, $f12, $f20      # $f14 = (2n+3)
    add.s $f16, $f14, $f20      # $f16 = (2n+4)
    mul.s $f10, $f12, $f14      # current denominator (2n+2)(2n+4)
    mul.s $f10, $f10, $f16      # $f10 = (2n+2)(2n+3)(2n+4)

    div.s $f24, $f8, $f10       # $f24 = result
    add.s $f0, $f0, $f24        # update the sum

    add.s $f18, $f18, $f20      # increment n counter
    mov.s $f24, $f18            # f24 = current n count
    cvt.w.s $f24, $f24          # convert representation to float
    mfc1 $t4, $f24              # 
    beq $a0, $t4, done

    j single_forward


done:
    add.s $f0, $f0, $f4  # add 3 to result

    jr $ra

任何让我开始的提示或建议将不胜感激，谢谢！