;====================================================
; Creates a constant string
;
; This will create both a label to the string and a variable szName.size for its size.
;
; Must be used in the constant section.
;
; The size of the string does not include the NUL character at the end of it,
;
; @param szName Name of the label of the string
; @param szString String
macro cstring szName,[szString] {
  common label szName
  forward db szString
  lenof.#szName equ $ - szName
  db 0
}

;====================================================
; Copies a constant string to an area of Memory
;
; @param szName label of the constant string
; @param edi points to destination
; @affects esi edi ecx
; @note User is reponsible of adding the NUL character at the end of the string
macro cstring_copy szName {
  mov esi,szName

  if (lenof.szName) > 4
    mov ecx,(lenof.szName) / 4
    rep movsd
  end if

  if ((lenof.szName) and 3) > 0
    mov ecx,(lenof.szName) and 3
    rep movsb
  end if
}
    

; In data
cstring szTest, "This is a test"

; Later in code
  mov ecx,(lenof.szTest) /4
  rep movsd

  mov ecx,(lenof.szTest) and 3
  rep movsb
    

;====================================================
; Creates a constant string
;
; This will create both a label to the string and a variable szName.size for its size.
;
; Must be used in the constant section.
;
; The size of the string does not include the NUL character at the end of it,
;
; @param szName Name of the label of the string
; @param szString String
macro cstring szName,[szString] {
  common label szName
  forward db szString
  lenof.#szName equ $ - szName
  db 0
}

;====================================================
; Copies a constant string to an area of Memory
;
; @param szText label of the constant string
; @param edi points to destination
; @affects esi edi ecx
; @note User is reponsible of adding the NUL character at the end of the string
macro cstring_cpy szText {
  local szLen
  local bRemain
  local nDwords

  szLen = lenof.#szText ; Length of string

  ; Do we need to do anything at all?
  if szLen > 0
    ; Yes, if we are here.
    mov esi,szText   ; Set pointer

    ; Number of dwords to move
    nDwords = szLen / 4

    ; we use rep movsd if we have at least 4 dwords
    if nDwords > 3
      mov ecx,szLen / 4    ; Number of dwords to move
      rep movsd                         ; move them
    else if nDwords > 2
      ; 3 dwords
      movsd
      movsd
      movsd
    else if nDwords > 1
      ; 2 dwords
      movsd
      movsd
    else if nDwords > 0
      ; 1 dword
      movsd
    end if

    bRemain = szLen and 3 ; Remaining bytes

    ; Do we need to move 3 bytes?
    if bRemain > 2
      ; Move 3 bytes
      movsw
      movsb
    else if bRemain > 1   ; Do we need to move 2 bytes?
      ; Move 2 bytes
      movsw
    else if bRemain > 0  ; Do we need to move 1 byte?
      ; Move 1 byte
      movsb
    end if
  end if
}
    

lenof.#szName equ $ - szName    

lenof#.#szName equ $ - szName