; Clears all memory accociated with a thread
; inputs    a  = Thread ID
FreeThreadMem:
    push af
    push de
    push hl
    push ix
    ld hl,UserRAM
    xor a
FTMLoop     cp (hl)
        jr nz,FTMSkip
        push hl
        pop ix
        call FreeMem
FTMSkip     inc hl
        ld e,(hl)
        inc hl
        ld d,(hl)
        add hl,de       ; jump to next section
        ld de,UserRAMEnd    ; get the end of UserRAM
        sbc hl,de       ; compare
        add hl,de
        jr nz,FTMLoop       ; loop again if hl < UserRAMEnd
    pop ix
    pop hl
    pop de
    pop af
    ret