; These macros are from RetroForth
macro dup
{
        sub esi,4
        mov [esi],eax
}
macro drop { lodsd }
macro swap { xchg eax, [esi] }
macro upsh a
{
        dup
        mov eax, a
}
macro upop a
{
        mov a, eax
        drop
}



; LIFO Stack example
; Adapted from the RetroForth 4.x/5/x/6.x/7.x source code
; This implements enough of the stack to enable basic Forth primitives
; (implemented by macros) to be used. Provided primitives are dup, drop,
; and swap.
;
format ELF executable
entry start

start:
    mov esi, mystack  (ESI points to stack memory)

    upsh 1  ;  Put the numbers 1 - 5 on the stack
    upsh 2  ;
    upsh 3  ;
    upsh 4  ;
    upsh 5  ;  At this point, 1 is on the bottom and 5 is on the top

    upop ebx   ; get the top value from stack and place in ebx
                    ; subsequent calls to 'upop' will fetch the other values
                    ; from the stack

    xor eax, eax     ;   Exit the application (this is for Linux)
    inc eax             ;
    int 0x80            ;


stack_space rb 100*4   ; Reserve space for 100 numbers
mystack       rb 4          ; Start of the stack
stacK_buffer rb 10*4     ; 10 space buffer for overflows