Brainfuck interpreter xd

Sarr = 0
Sfmp = 0
Sptr = 0
Smax = 0
Sfpt = 0

def Sinit():
    Sarr = list()
    Sfmp = list()
    Sptr = 0
    Smax = 0
    Sfpt = 0

def Srun(prgm,bdmm=0,bdcp=0,ovflcr=True):
    i = 0
    while i < len(prgm) and prgm[i]:
        if prgm[i] == ">":
            if Smax < bdmm or bdmm == 0:
                Sptr = Sptr + 1
            elif ovflcr:
                return -1
            if Sptr > (Smax - 1):
                Smax = Smax + 1
                Sarr[Sptr] = 0
        if prgm[i] == "<":
            if Sptr > 0:
                Sptr = Sptr - 1
            elif ovflcr:
                return -1
        if prgm[i] == "+":
            if Sarr[Sptr] < bdcp or bdmm == 0:
                Sarr[Sptr] = Sarr[Sptr] + 1
            elif ovflcr:
                return -1
        if prgm[i] == "-":
            if Sarr[Sptr] > 0:
                Sarr[Sptr] = Sarr[Sptr] - 1
            elif ovflcr:
                return -1
        if prgm[i] == "[":
            m = 0
            j = 1
            k = i + 1
            t = ""
            while j > 0:
                if prgm[k] == "[":
                    j = j + 1
                if prgm[k] == "]":
                    j = j - 1
                if j > 0:
                    t[m] = prgm[k]
                if k == len(prgm) - 1:
                    return -1
                m = m + 1
                k = k + 1
            Sfmp[Sfpt] = t
            Sfpt = Sfpt + 1
            while Sarr[Sptr] > 0:
                w = Srun(t,bdmm,bdcp,ovflcr)
                if w == -1:
                    return -1
                i = i + w
            i = k + 1
            continue
        if prgm[i] == ",":
            Sarr[Sptr] = eval(input("???"))
            if ovflcr:
                return -1
            if Sarr[Sptr] >= bdcp:
                Sarr[Sptr] = bdcp - 1
        if prgm[i] == ".":
            print(str(unichr(Sarr[Sptr])))
        if prgm[i] == "*":
            if i == len(prgm) - 1:
                if ovflcr:
                    return -1
            elif prgm[i + 1] == ">":
                prgm[i + 1] = "<"
            elif prgm[i + 1] == "<":
                prgm[i + 1] = "+"
            elif prgm[i + 1] == "+":
                prgm[i + 1] = "-"
            elif prgm[i + 1] == "-":
                prgm[i + 1] == "["
            elif prgm[i + 1] == "[":
                prgm[i + 1] = "]"
            elif prgm[i + 1] == "]":
                prgm[i + 1] = "*"
             elif prgm[i + 1] == "*":
                prgm[i + 1] = ">"
        if prgm[i] == "#":
            i = i + 1
            while i < len(prgm):
                if prgm[i] == "#":
                    break
                i = i + 1
        if prgm[i] == "?":
            if Smax < bdmm:
                Sarr[Sptr] = Smax
            elif ovflcr:
                return -1
        if prgm[i] == "!":
            if Sarr[Sptr] < Sfpt:
                i = i + Srun(Sfmp[Sarr[Sptr]],bdmm,bdcp,ovflcr)
            elif ovflcr:
                return -1
        i = i + 1
    return i