sonic3k.macros.asm

; simplifying macros and functions
; nameless temporary symbols should NOT be used inside macros because they can interfere with the surrounding code
; normal labels should be used instead (which automatically become local to the macro)

; sign-extends a 32-bit integer to 64-bit
; all RAM addresses are run through this function to allow them to work in both 16-bit and 32-bit addressing modes
ramaddr function x,(-(x&$80000000)<<1)|x

; makes a VDP command
vdpComm function addr,type,rwd,(((type&rwd)&3)<<30)|((addr&$3FFF)<<16)|(((type&rwd)&$FC)<<2)|((addr&$C000)>>14)

; values for the type argument
VRAM = %100001
CRAM = %101011
VSRAM = %100101

; values for the rwd argument
READ = %001100
WRITE = %000111
DMA = %100111

; tells the VDP to copy a region of 68k memory to VRAM or CRAM or VSRAM
dma68kToVDP macro source,dest,length,type
	lea	(VDP_control_port).l,a5
	move.l	#(($9400|((((length)>>1)&$FF00)>>8))<<16)|($9300|(((length)>>1)&$FF)),(a5)
	move.l	#(($9600|((((source)>>1)&$FF00)>>8))<<16)|($9500|(((source)>>1)&$FF)),(a5)
	move.w	#$9700|(((((source)>>1)&$FF0000)>>16)&$7F),(a5)
	move.w	#((vdpComm(dest,type,DMA)>>16)&$FFFF),(a5)
	move.w	#(vdpComm(dest,type,DMA)&$FFFF),(DMA_trigger_word).w
	move.w	(DMA_trigger_word).w,(a5)
	; From '  § 7  DMA TRANSFER' of https://emu-docs.org/Genesis/sega2f.htm:
	;
	; "In the case of ROM to VRAM transfers,
	; a hardware feature causes occasional failure of DMA unless the
	; following two conditions are observed:
	;
	; --The destination address write (to address $C00004) must be a word
	;   write.
	;
	; --The final write must use the work RAM.
	;   There are two ways to accomplish this, by copying the DMA program
	;   into RAM or by doing a final "move.w ram address $C00004""
    endm

; tells the VDP to fill a region of VRAM with a certain byte
dmaFillVRAM macro byte,addr,length
	lea	(VDP_control_port).l,a5
	move.w	#$8F01,(a5) ; VRAM pointer increment: $0001
	move.l	#(($9400|((((length)-1)&$FF00)>>8))<<16)|($9300|(((length)-1)&$FF)),(a5) ; DMA length ...
	move.w	#$9780,(a5) ; VRAM fill
	move.l	#$40000080|(((addr)&$3FFF)<<16)|(((addr)&$C000)>>14),(a5) ; Start at ...
	move.w	#(byte)<<8,(VDP_data_port).l ; Fill with byte
loop:	move.w	(a5),d1
	btst	#1,d1
	bne.s	loop	; busy loop until the VDP is finished filling...
	move.w	#$8F02,(a5) ; VRAM pointer increment: $0002
    endm

; calculates initial loop counter value for a dbf loop
; that writes n bytes total at 4 bytes per iteration
bytesToLcnt function n,n>>2-1

; calculates initial loop counter value for a dbf loop
; that writes n bytes total at 2 bytes per iteration
bytesToWcnt function n,n>>1-1

; calculates initial loop counter value for a dbf loop
; that writes n bytes total at x bytes per iteration
bytesToXcnt function n,x,n/x-1

; fills a region of 68k RAM with 0
clearRAM macro addr,length
    if ((addr)&$8000)==0
	lea	(addr).l,a1
    else
	lea	(addr).w,a1
    endif
	moveq	#0,d0
    if ((addr)&1)
	move.b	d0,(a1)+
    endif
	move.w	#bytesToLcnt(length - ((addr)&1)),d1
.loop:	move.l	d0,(a1)+
	dbf	d1,.loop
    if ((length - ((addr)&1))&2)
	move.w	d0,(a1)+
    endif
    if ((length - ((addr)&1))&1)
	move.b	d0,(a1)+
    endif
    endm

; tells the Z80 to stop, and waits for it to finish stopping (acquire bus)
stopZ80 macro
	move.w	#$100,(Z80_bus_request).l ; stop the Z80
loop:	btst	#0,(Z80_bus_request).l
	bne.s	loop ; loop until it says it's stopped
    endm

; tells the Z80 to start again
startZ80 macro
	move.w	#0,(Z80_bus_request).l    ; start the Z80
    endm

; function to make a little-endian 16-bit pointer for the Z80 sound driver
z80_ptr function x,(x)<<8&$FF00|(x)>>8&$7F|$80

; macro to declare a little-endian 16-bit pointer for the Z80 sound driver
rom_ptr_z80 macro addr
	dc.w z80_ptr(addr)
    endm

; macros to convert from tile index to art tiles, block mapping or VRAM address.
make_art_tile function addr,pal,pri,((pri&1)<<15)|((pal&3)<<13)|(addr&tile_mask)
tiles_to_bytes function addr,((addr&$7FF)<<5)

; function to calculate the location of a tile in plane mappings with a width of 40 cells
planeLocH28 function col,line,(($50 * line) + (2 * col))

; macro for generating water palette transition tables
watertransheader macro {INTLABEL}
__LABEL__ label *
	; Number of entries in list minus one
	dc.w (((__LABEL___End - __LABEL__ - 2) / 2) - 1)
	endm

; macro for generating level select strings
levselstr macro str
	save
	codepage	LEVELSELECT
	dc.b strlen(str)-1, str
	restore
    endm

; codepage for level select
	save
	codepage LEVELSELECT
	charset '0','9', 16
	charset 'A','Z', 30
	charset 'a','z', 30
	charset '*', 26
	charset $A9, 27	; '?'
	charset ':', 28
	charset '.', 29
	charset ' ',  0
	restore

; macros for defining animated PLC script lists
zoneanimstart macro {INTLABEL}
__LABEL__ label *
zoneanimcount := 0
zoneanimcur := "__LABEL__"
	dc.w zoneanimcount___LABEL__	; Number of scripts for a zone (-1)
    endm

zoneanimend macro
zoneanimcount_{"\{zoneanimcur}"} = zoneanimcount-1
    endm

zoneanimdeclanonid := 0

zoneanimdecl macro duration,artaddr,vramaddr,numentries,numvramtiles
zoneanimdeclanonid := zoneanimdeclanonid + 1
start:
	dc.l (duration&$FF)<<24|artaddr
	dc.w tiles_to_bytes(vramaddr)
	dc.b numentries, numvramtiles
zoneanimcount := zoneanimcount + 1
    endm

; macro for declaring a "main level load block" (MLLB)
levartptrs macro plc1,plc2,palette,art1,art2,map16x161,map16x162,map128x1281,map128x1282
	dc.l (plc1<<24)|art1
	dc.l (plc2<<24)|art2
	dc.l (palette<<24)|map16x161
	dc.l (palette<<24)|map16x162
	dc.l map128x1281
	dc.l map128x1282
    endm

; macro for a pattern load request list header
; must be on the same line as a label that has a corresponding _End label later
plrlistheader macro {INTLABEL}
__LABEL__ label *
	dc.w (((__LABEL___End - __LABEL__Plc) / 6) - 1)
__LABEL__Plc:
    endm

; macro for a pattern load request
plreq macro toVRAMaddr,fromROMaddr
	dc.l	fromROMaddr
	dc.w	tiles_to_bytes(toVRAMaddr)
    endm

; macro for a debug object list header
; must be on the same line as a label that has a corresponding _End label later
dbglistheader macro {INTLABEL}
__LABEL__ label *
	dc.w ((__LABEL___End - __LABEL__ - 2) / $A)
    endm

; macro to define debug list object data
dbglistobj macro   obj, mapaddr, subtype, frame, vram
	dc.l frame<<24|obj
	dc.l subtype<<24|mapaddr
	dc.w vram
    endm

tribyte macro val
	if "val"<>""
		dc.b (val >> 16)&$FF,(val>>8)&$FF,val&$FF
		shift
		tribyte ALLARGS
	endif
    endm

; macro to define a palette script pointer
palscriptptr	macro header, data
	dc.w data-header, 0
	dc.l header
._headpos :=	header
    endm

; macro to define a palette script header
palscripthdr	macro palette, entries, value
	dc.w (palette)&$FFFF
	dc.b entries-1, value
    endm

; macro to define a palette script data
palscriptdata	macro frames, data
.framec :=	frames-1
	shift
	dc.w ALLARGS
	dc.w .framec
    endm

; macro to repeat script from start
palscriptrept	macro header
	dc.w -4
    endm

; macro to define loop from start for x number of times, then initialize with new header
palscriptloop	macro header
	dc.w -8, header-._headpos
._headpos :=	header
    endm

; macro to run the custom script routine
palscriptrun	macro header
	dc.w -$C
    endm