testcode.tvm

.PRELOAD 33,E,n,t,e,r,32,N,a,m,e,:,32,!
.CODE_SEGMENT
; point register 0 to the next location in memory
NEXT 0
NEXT 0
NEXT 0
NEXT 0
NEXT 0
NEXT 0
NEXT 0
NEXT 0
NEXT 0
NEXT 0
NEXT 0
NEXT 0
NEXT 0
NEXT 0
; point register 2 to beginning of message
NEXT 2
LABEL printMessage
PUTC 2
NEXT 2
CMP 1 2
JE startInput
CMP 1 1
JE printMessage
LABEL startInput
; get a character from input
GETC 0
; compare register 1 ('!') to 0 (input char) -- subtracts 0 from 1 and sets zero flag if they are equal
CMP 1 0
; move register 0 to next location in mem
NEXT 0
; Jump to label d if the previous compare set the zero flag
JE primeInput
; compare register 1 to itself, this sets up an unconditional jump
CMP 1 1
; unconditionally jump to label t
JE startInput
LABEL primeInput
NEXT 2
LABEL printInput
; print char from register 2, which points to the original location of register 0
PUTC 2
; move reg 2 to the next value
NEXT 2
; check if Reg 2 is at char '!'
CMP 1 2
; if it is, jump to label r
JE endProgram
; unconditionally jump back to d until reg 2 is '!'
CMP 1 1
JE printInput
LABEL endProgram
; operation has to be here since there is no halt command
INC 1