Type Instruccion
    opcode As String * 5
    operand As Integer
    has_operand As Integer
End Type

Dim Shared As Integer datasize = 1, nstrings = 2

Dim Shared As String strings(1)
strings(0) = "count is: "
strings(1) = Chr(10)

Dim Shared As Instruccion code(17)
code(0)  = Type("push" , 1 , 1)
code(1)  = Type("store", 0 , 1)
code(2)  = Type("fetch", 0 , 1)
code(3)  = Type("push" , 10, 1)
code(4)  = Type("lt"   , 0 , 0)
code(5)  = Type("jz"   , 17, 1)
code(6)  = Type("push" , 0 , 1)
code(7)  = Type("prts" , 0 , 0)
code(8)  = Type("fetch", 0 , 1)
code(9)  = Type("prti" , 0 , 0)
code(10) = Type("push" , 1 , 1)
code(11) = Type("prts" , 0 , 0)
code(12) = Type("fetch", 0 , 1)
code(13) = Type("push" , 1 , 1)
code(14) = Type("add"  , 0 , 0)
code(15) = Type("store", 0 , 1)
code(16) = Type("jmp"  , 2 , 1)
code(17) = Type("halt" , 0 , 0)


' Stack, memory data
Dim Shared As Integer stack(100), dato(10)
Dim Shared As Integer sp_ = 0, pc_ = 0

Function pop() As Integer
    sp_ -= 1
    Return stack(sp_)
End Function

Sub push(valor As Integer)
    stack(sp_) = valor
    sp_ += 1
End Sub

Dim As Boolean running = True

Do While running
    Dim As Instruccion inst = code(pc_)
    pc_ += 1

    Select Case inst.opcode
    Case "push"
        push(inst.operand)
    Case "store"
        dato(inst.operand) = pop()
    Case "fetch"
        push(dato(inst.operand))
    Case "add"
        Dim As Integer b = pop(), a = pop()
        push(a + b)
    Case "lt"
        Dim As Integer b = pop(), a = pop()
        push(Iif(a < b, 1, 0))
    Case "jz"
        Dim As Integer cond = pop()
        If cond = 0 Then pc_ = inst.operand
    Case "jmp"
        pc_ = inst.operand
    Case "prts"
        'Dim As Integer idx = pop()
        Print strings(pop());
    Case "prti"
        Print pop();
    Case "halt"
        running = False
    End Select
Loop

Sleep