;; ======================================================================== ;;
;;  TRACKER.MAC                                                             ;;
;;  Arnauld Chevallier                                                      ;;
;; ======================================================================== ;;

    IF (DEFINED _TRACKER_MAC) = 0

_TRACKER_MAC EQU 1

_NOTE_OFFSET EQU $10

;; ======================================================================== ;;
;;  NOTES       n0, n1, n2, n3                                              ;;
;;  Defines 4 notes at once, by invokating the NOTE macro 4 times           ;;
;;                                                                          ;;
;;  ARGUMENTS                                                               ;;
;;      n0  String defining note #0.                                        ;;
;;      n1  String defining note #1.                                        ;;
;;      n2  String defining note #2.                                        ;;
;;      n3  String defining note #3.                                        ;;
;; ======================================================================== ;;
MACRO NOTES(n0, n1, n2, n3)
      ;
      LISTING "code"
      NOTE(%n0%)
      NOTE(%n1%)
      NOTE(%n2%)
      NOTE(%n3%)
      LISTING "prev"
ENDM

;; ======================================================================== ;;
;;  NOTE        n                                                           ;;
;;  Defines 1 note                                                          ;;
;;                                                                          ;;
;;  ARGUMENTS                                                               ;;
;;      n   String defining the note.                                       ;;
;;                                                                          ;;
;;      String format:  NnO IVL                                             ;;
;;                                                                          ;;
;;      N = Note (C, D, E, F, G, A, B)                                      ;;
;;      n = '-' or '#'                                                      ;;
;;      O = Octave (1 - 7)                                                  ;;
;;      I = new Instrument (1 - F, or 0 for unchanged)                      ;;
;;      V = Volume (0 - F)                                                  ;;
;;      L = Length (0 - F)                                                  ;;
;;                                                                          ;;
;;      The string "NUL" can be used instead of the NnO parameters to       ;;
;;      indicate that the current note is actually not changed.             ;;
;;      (Including such directives is required when a note lasts longer     ;;
;;      than the maximal length which can be specified.)                    ;;
;;                                                                          ;;
;;      The string "OFF" can also be used as a special code to disable      ;;
;;      ticks on the ECS.                                                   ;;
;;                                                                          ;;
;;  EXAMPLES                                                                ;;
;;      NOTE("C-3 1F1")                                                     ;;
;;      NOTE("D#4 0F1")                                                     ;;
;;      NOTE("NUL 0F1")                                                     ;;
;; ======================================================================== ;;
MACRO NOTE(n)
      ;
      IF STRLEN(%n%) > 0
      ; instrument
HEX2DEC(_i, ASC(%n%, 4))
      ; volume
HEX2DEC(_v, ASC(%n%, 5))
      ; length
HEX2DEC(_l, ASC(%n%, 6))
      ; "OFF" ?
      IF ASC(%n%, 0) = 79 AND ASC(%n%, 1) = 70 AND ASC(%n%, 2) = 70
      DECLE  $8000 + _l * $10 + (15-_v)
      ELSE
      ; "NUL" ?
      IF ASC(%n%, 0) = 78 AND ASC(%n%, 1) = 85 AND ASC(%n%, 2) = 76
            IF _i <> 0
      DECLE  $8000 + _l * $10 + (15-_v)
      DECLE (_i - 1) * 3
            ELSE
      DECLE  _l * $10 + (15-_v)
            ENDI
      ELSE
            INC_NOTE(%n%, _i, _v, _l)
      ENDI
      ENDI
      ENDI
ENDM

;; ======================================================================== ;;
;;  INC_NOTE    n, i, v, l                                                  ;;
;;  Inludes the decle(s) defining a note                                    ;;
;;                                                                          ;;
;;  ARGUMENTS                                                               ;;
;;      n   Value of the note.                                              ;;
;;      i   Instrument used.                                                ;;
;;      v   Volume used.                                                    ;;
;;      l   Length of the note.                                             ;;
;; ======================================================================== ;;
MACRO INC_NOTE(n, i, v, l)
      ; note
_n0   SET   ASC(%n%, 0)
      IF (_n0 < 65) OR (_n0 > 71)
            ERR   "Invalid note"
      ENDI
      ; conversion letter -> value
      ;          ABCDEFG
_n1   SET   ASC("JLACEFH", _n0-65) - 64
      ; sharp ?
      IF ASC(%n%, 1) = 35
_n1   SET   _n1 + 1
      ELSE
            ; minus ?
            IF ASC(%n%, 1) <> 45
                  ERR   "Invalid note"
            ENDI
      ENDI
      ; octave
_o    SET   ASC(%n%, 2)
      IF (_o < 49) OR (_o > 55)
            ERR   "Invalid octave"
      ENDI
      ; value
_n2   SET   (_n1 + 12 * (_o - 49)) - _NOTE_OFFSET
      IF %i% <> 0
      DECLE $8000 + _n2 * $100 + %l% * $10 + (15-%v%)
      DECLE (%i% - 1) * 3
      ELSE
      DECLE _n2 * $100 + %l% * $10 + (15-%v%)
      ENDI
ENDM

;; ======================================================================== ;;
;;  HEX2DEC     e, s                                                        ;;
;;  Converts a hexadecimal symbol to its decimal value                      ;;
;;                                                                          ;;
;;  ARGUMENTS                                                               ;;
;;      e   Expression to which the result will be affected.                ;;
;;      s   Hexadecimal value.                                              ;;
;; ======================================================================== ;;
MACRO HEX2DEC(e, s)
      ;
      IF (%s% >= 48) AND (%s% <= 57)
%e%   SET   %s% - 48
      ELSE
            IF (%s% >= 65) AND (%s% <= 70)
%e%   SET   %s% - 55
            ELSE
                  ERR   "Invalid hexa symbol"
            ENDI
      ENDI
ENDM

    ENDI