*** Header file used for creating and calling GMOD modules *** * Public domain by Bryan Ford ifnd BRY_GMOD_I BRY_GMOD_I set 1 ifnd EXEC_TYPES_I include "exec/types.i" endc *** This is the layout of the first part of every GMOD module. STRUCTURE GMOD,0 ; The first four longwords contain various important values. ULONG gmod_ID ; Must be 'GMOD' ULONG gmod_Maker ; ID of creator program (ASCII, like IFF ID's) ULONG gmod_LoadAddress ; Address at which to load module (0L = any) ULONG gmod_MaxVecOfs ; Offset of end of vector table (numvecs+4)*4 ; From here on are the entrypoints ; (actual instructions, not just vector pointers) LONG gmod_InitMusic ; Initialize the module LONG gmod_StartMusic ; Start playing (d0.l = song number) LONG gmod_StopMusic ; Stop playing LONG gmod_EndMusic ; Shut down the module LONG gmod_Reserved ; Pause LONG gmod_ContinueMusic ; Restart after pause LONG gmod_VBlank50 ; VBlank interrupt (50Hz) LONG gmod_VBlank60 ; VBlank interrupt (60Hz) LONG gmod_Channel0 ; Channel 0 loaded interrupt LONG gmod_Channel1 ; Channel 1 loaded interrupt LONG gmod_Channel2 ; Channel 2 loaded interrupt LONG gmod_Channel3 ; Channel 3 loaded interrupt LONG gmod_GetNumSongs ; Get number of songs (d0.l) LONG gmod_GetSongName ; Get description of a song (d1.l) into (d0.p) LONG gmod_GetSongAuthor ; Get the name of a song's author (d1.l) into (d0.p) LONG gmod_GetFrequency ; Get the timing frequency for the song (d0.l) LONG gmod_TimerTick ; Routine to call at specified frequency LONG gmod_GetMakerName ; Get name of creator program LONG gmod_Hook ; Specify a Hook to call on various events LONG gmod_Jump ; Jump to sequence/time/whatever LABEL gmod_SIZEOF ; Don't depend on this when playing a GMOD! ; Flags for the gmod_Hook call - similar to Intuition's IDCMP flags BITDEF GMODH,REPEAT,0 ; Call when music repeats BITDEF GMODH,SEQUENCE,1 ; Call when sequence changes *** Use these macros to help when playing GMOD modules. *** All of them assume that the pointer to the GMOD module is in a5. * Branch if a vector offset (gmod_xxx) is in range gmodbin macro ; DReg,label cmp.l gmod_MaxVecOfs(a5),\1 bcs \2 endm * Branch if a vector offset (gmod_xxx) is out of range gmodbout macro ; DReg,label cmp.l gmod_MaxVecOfs(a5),\1 bcc \2 endm * Call a GMOD vector WITHOUT checking - you must first make sure it's there! gmodcall macro ; DReg jsr 0(a5,\1) endm * Same as gmodcall, but with an immediate (as opposed to register) vector offset gmodcalli macro ; Offset jsr \1(a5) endm * This is what you'll usually use when calling GMOD entrypoints - * it first checks to make sure the entrypoint is available, THEN calls * it. The GMOD pointer must be in a5, and the vector offset must * be in some data register. gmodmaycall macro ; DReg cmp.l gmod_MaxVecOfs(a5),\1 dc.w $6404 ; bra.s *+2 gmodcall \1 endm *** Use these macros if you are DEFINING a GMOD header. This makes it *** easier if you don't happen to know the lengths of the various instructions *** by memory. * Do-nothing entrypoint - stick this in entrypoints you don't need or can't support gmodnop macro ; Do-nothing entry in a GMOD header rts nop endm * Branch to some other location (makes the GMOD header act like a jump table) gmodbra macro ;