HelloWorld_manual.msm

;; Advanced Hallo-World example, involving basic memory operations
%include "../msmlib/stdlib.mlb"

; Define SPACE ascii code
%define SPACE 32

jmp main ; Skip function definitions

write_mem:
    push 0 ; I
    swap 1
write_mem_loop:
    ; Writing one char to the memory at I
    swap 1
    dup 0
    dup 3
    write8

    ; Incrementing the I
    push 1
    plusi

    ; Checking if next char is 0
    swap 2
    push 0
    equal
    not

    ; jmp if next char is not 0
    ; else return
   jmpif write_mem_loop
    ret

print_mem:
    ; Given: I
    swap 1 ; Swap return addr to the bottom of the stack
print_mem_loop:

    ; Reading and printing char from I
    dup 0
    read8
    int print_char

    ; Zeroing memory at I
    dup 0
    push 0
    write8

    ; Decrement I
    push 1
    minusi

    ; Checking if I equal to -1
    push -1
    dup 1
    equal
    not

   ; jmp if I is not -1
   ; else return
   jmpif print_mem_loop
   drop ; cleanup I
   ret

; Main label
main:
    ; Pushing 0 terminated str in reverse order as ascii codes to the stack.
    push 0      ; null terminate

    push 72     ; H
    push 101    ; e
    push 108    ; l
    push 108    ; l
    push 111    ; o
    push SPACE
    push 87     ; W
    push 111    ; o
    push 114    ; r
    push 108    ; l
    push 100    ; d
    push 33     ; !
    push NL

    ; Writing the str to the memory
    call write_mem

    ; Printing
    call print_mem
    hlt