; #############################    macro    #################################

; readCmdBuf
; ----------
; cmd buf   --> BC  --> cmd buf
;               A   --> value
;
; read 1 byte from command buffer
; = 11 cycles

            macro   readCmdBuf

            LD      A, (BC)         ;                       ' 7     |
            INC     C               ; next                  ' 4     | 11

            endm


; readBeU16CmdBuf
; ---------------
; cmd buf   --> BC  --> cmd buf
;               A   --> ?
;               HL  --> value
;
; read big endian u16 (2 bytes) from command buffer
; = 30 cycles

            macro   readBeU16CmdBuf

            readCmdBuf              ;                       ' 11     |
            LD      H, A            ;                       ' 4      |
            readCmdBuf              ;                       ' 11     | 30
            LD      L, A            ;                       ' 4      |

            endm


; readBeU16CmdBuf_DE
; ------------------
; cmd buf   --> BC  --> cmd buf
;               A   --> ?
;               DE  --> value
;
; read big endian u16 (2 bytes) from command buffer
; = 30 cycles

            macro   readBeU16CmdBuf_DE

            readCmdBuf              ;                       ' 11     |
            LD      D, A            ;                       ' 4      |
            readCmdBuf              ;                       ' 11     | 30
            LD      E, A            ;                       ' 4      |

            endm


; readU24CmdBuf
; -------------
; cmd buf   --> BC  --> cmd buf
;               HL  --> low word value
;               A   --> high byte value
;
; read u24 (3 bytes) from command buffer
; = 41 cycles

            macro   readU24CmdBuf

            readCmdBuf              ;                       ' 11     |
            LD      L, A            ;                       ' 4      |
            readCmdBuf              ;                       ' 11     | 41
            LD      H, A            ;                       ' 4      |
            readCmdBuf              ;                       ' 11     |

            endm


; readU24CmdBuf_DE
; ----------------
; cmd buf   --> BC  --> cmd buf
;               DE  --> low word value
;               A   --> high byte value
;
; read u24 (3 bytes) from command buffer
; = 41 cycles

            macro   readU24CmdBuf_DE

            readCmdBuf              ;                       ' 11     |
            LD      E, A            ;                       ' 4      |
            readCmdBuf              ;                       ' 11     | 41
            LD      D, A            ;                       ' 4      |
            readCmdBuf              ;                       ' 11     |

            endm


; hasEmptyComBuffer
; -----------------
;           HL  --> ?
;           A   --> ?
;
; (A == 0) or Z flag set = FM or PSG com buffer empty
; up to 67 cycles

            macro hasEmptyComBuffer

            isFMComBufferEmpty          ;                           ' 30    |
            JR      Z, .end             ;                           ' 7     | 37

            isPSGComBufferEmpty         ;                           ' 30    | (67)

.end

            endm


; logRemainingSamples
; -------------------
;           A   --> ?
;           D   --> ?
;
; log number of remaining sample in PCM buffer

            macro logRemainingSamples var

            EXX                                     ;
            LD      A, C                            ; A = curr played sample index
            EXX                                     ;
            LD      D, A
            getRemainingSample
            LD      (var), A                        ; save duration in sample

            endm