[megadrive.git] / hexed / hexed.s

##################################################
#                                                #
# Assemble with gas                              #
#   --register-prefix-optional --bitwise-or      #
#                                                #
##################################################

.text
.globl main
.globl VBL

##################################################
#                                                #
#        Register and bitmask definitions        #
#                                                #
##################################################

.equ GFXDATA, 		0xc00000
.equ GFXCNTL, 		0xc00004

.equ VDP0_E_HBI, 	0x10
.equ VDP0_E_DISPLAY, 	0x02 
.equ VDP0_PLTT_FULL, 	0x04 

.equ VDP1_SMS_MODE,	0x80
.equ VDP1_E_DISPLAY,	0x40
.equ VDP1_E_VBI,	0x20
.equ VDP1_E_DMA,	0x10
.equ VDP1_NTSC,		0x00
.equ VDP1_PAL,		0x08
.equ VDP1_RESERVED,	0x04

.equ VDP12_STE,		0x08
.equ VDP12_SCREEN_V224,	0x00
.equ VDP12_SCREEN_V448,	0x04
.equ VDP12_PROGRESSIVE,	0x00
.equ VDP12_INTERLACED,	0x02
.equ VDP12_SCREEN_H256,	0x00
.equ VDP12_SCREEN_H320,	0x81

.equ VDP16_MAP_V32,	0x00
.equ VDP16_MAP_V64,	0x10
.equ VDP16_MAP_V128,	0x30
.equ VDP16_MAP_H32,	0x00
.equ VDP16_MAP_H64,	0x01
.equ VDP16_MAP_H128,	0x03

.equ MMODE_MAIN,	0
.equ MMODE_VAL_INPUT,	1
.equ MMODE_EDIT_VAL,	2
.equ MMODE_GOTO,	3


##################################################
#                                                #
#                   MACROS                       #
#                                                #
##################################################


/* Write val to VDP register reg */
.macro write_vdp_reg reg val
	move.w #((\reg << 8) + 0x8000 + \val),(a3)
.endm


/* For immediate addresses */
.macro VRAM_ADDR reg adr
	move.l #(((0x4000 + (\adr & 0x3fff)) << 16) + (\adr >> 14)),\reg
.endm


.macro CRAM_ADDR reg adr
	move.l	#(((0xc000 + (\adr & 0x3fff)) << 16) + (\adr >> 14)),\reg
.endm


# make VDP word from address adr and store in d0
.macro XRAM_ADDR_var adr
	move.l \adr,d0
	lsl.l #8,d0
	lsl.l #8,d0
	rol.l #2,d0
	lsl.b #2,d0
	lsr.l #2,d0
.endm


.macro VRAM_ADDR_var adr
	XRAM_ADDR_var \adr
	or.l #0x40000000,d0
.endm


.macro CRAM_ADDR_var adr
	XRAM_ADDR_var \adr
	or.l #0xc0000000,d0
.endm


.macro VSCROLL_ADDR reg adr
	move.l	#(((0x4000 + (\adr & 0x3fff)) << 16) + ((\adr >> 14) | 0x10)),\reg
.endm


.macro HSCROLL_ADDR reg adr
	move.l #(((0x4000 + (\adr & 0x3fff)) << 16) + (\adr >> 14)),\reg
.endm


# convert tile coords in d0, d1 to nametable addr to a0
.macro XY2NT
	lsl.w		#6,d1
	add.w		d1,d0
	lsl.w		#1,d0
	movea.l		#0xe000,a0
	add.w		d0,a0
.endm

# check if some d-pad button (and modifier) is pressed
.macro do_dpad bit op val
	btst.l		#\bit,d0
	beq		0f
	\op.l		\val,a6
	bra		dpad_end
0:
.endm

# convert a6 to normal addr
#  destroys d0
.macro mk_a6_addr reg
	move.l		a6,\reg
	moveq.l		#0,d0
	move.b		\reg,d0
	lsr.l		#8,\reg
	add.l		d0,\reg
.endm

.macro change_mode mode_new mode_back
	and.w		#0xc0ff,d7
	or.w		#(\mode_back<<11)|(\mode_new<<8),d7
.endm

#################################################
#                                               #
#                    DATA                       #
#                                               #
#################################################

colors:
	dc.w 0x0000,0x0eee,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000
	dc.w	0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000
	dc.w 0x0000,0x02e2,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000
	dc.w	0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000
	dc.w 0x0000,0x0e44,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000
	dc.w	0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000
colors_end:


sprite_data:
	/*         Y        size     link          attr        X */
	dc.w       0;  dc.b 0x05;  dc.b 0;  dc.w 0x6002;  dc.w 0
sprite_data_end:

txt_edit:
	.ascii	"- edit -\0"
txt_a_confirm:
	.ascii	"A-confirm\0"

##################################################
#                                                #
#               MAIN PROGRAM                     #
#                                                #
##################################################
 
.align 2

main:
	/* mask irqs during init */
	move.w		#0x2700,sr

	movea.l		#0,a6
	move.l		#0x8000,d7
	moveq.l		#0,d6

	/* Init pads */
	move.b		#0x40,(0xa10009).l
	move.b		#0x40,(0xa10003).l

	/* Initialize VDP */
	jsr 		init_gfx

	/* Load color data */
	movea.l		#0,a0
	movea.l		#colors,a1
	moveq.l		#(colors_end-colors)/2,d0
	jsr		load_colors

	/* load patterns */
	movea.l		#0,a0
	movea.l		#font,a1
	move.l		#128,d0
	jsr		load_tiles

	/* generate A layer map */
	movea.l		#0xe000,a1
	move.l		#28-1,d4
lmaploop0:
	movea.l		a1,a0
	jsr		load_prepare

	move.l		#64/2-1,d3
0:	move.l		#0x00000000,(a0)
	dbra		d3,0b

	add.l		#64*2,a1
	dbra 		d4,lmaploop0

	/* generate B layer map */
	movea.l		#0xc000,a0
	jsr		load_prepare

	move.l		#64*28/2-1,d3
0:	move.l		#0x00000000,(a0)
	dbra		d3,0b

	/* upload sprite data */
	movea.l		#0xfc00,a0
	jsr		load_prepare
	movea.l		#sprite_data,a1

	move.l		#(sprite_data_end-sprite_data)/2-1,d3
0:	move.l		(a1)+,(a0)
	dbra		d3,0b

        move.w		#0x2000,sr

##################################################
#                                                #
#                 MAIN LOOP                      #
#                                                #
##################################################

# global regs:
# a6 = page_start[31:8]|cursor_offs[7:0]
# d7 = old_inputs[31:16]|edit_bytes[15:14]|g_mode_old[13:11]|g_mode[10:8]|irq_cnt[7:0]
# d6 = edit_word[31:8]|edit_done[7]|edit_pos[6:4]|autorep_cnt[3:0]

forever:


	jsr		wait_vsync
	bra 		forever
	

VBL:
	addq.b		#1,d7
	movem.l		d0-d5/a0-a5,-(a7)

	moveq.l		#0,d0
	move.w		d7,d0
	lsr.w		#6,d0
	and.w		#0x1c,d0
	move.l		(jumptab,pc,d0),a0
	jmp		(a0)
jumptab:
	dc.l		mode_main
	dc.l		mode_val_input
	dc.l		mode_edit_val	/* edit val in editor */
	dc.l		mode_goto
	dc.l		mode_main
	dc.l		mode_main
	dc.l		mode_main
	dc.l		mode_main

##################### main #######################

mode_main:
	clr.l		d1
	move.l		a6,d0
	move.b		d0,d1
	lsr.l		#8,d0
	move.l		d0,a1		/* current addr */
	lsr.b		#3,d1
	neg.b		d1
	add.b		#27-1,d1	/* line where the cursor sits */
	swap		d1

	movea.l		#0xe004,a2
	move.l		#27-1,d5	/* line counter for dbra */
	or.l		d1,d5

draw_column:
	move.l		a2,a0
	jsr		load_prepare

	/* addr */
	move.l		a1,d2
	moveq.l		#6,d3
	jsr		print_hex_preped

	/* 4 shorts */
	moveq.l		#4,d3
	moveq.l		#4-1,d4
draw_shorts:
	move.w		#' ',(a0)
	move.w		(a1)+,d2
	jsr		print_hex_preped
	dbra		d4,draw_shorts

	move.l		d5,d0
	swap		d0
	cmp.w		d5,d0
	beq		draw_cursor

draw_chars_pre:
	move.l		#(' '<<16)|' ',(a0)

	/* 8 chars */
	subq.l		#8,a1
	moveq.l		#8-1,d4
draw_chars:
	move.b		(a1)+,d0
	move.b		d0,d1
	sub.b		#0x20,d1
	cmp.b		#0x60,d1
	blo		0f
	move.w		#'.',d0
0:
	move.w		d0,(a0)
	dbra		d4,draw_chars

	add.w		#0x80,a2
	dbra		d5,draw_column

	/* status bar */
	movea.l		#0xe004+64*2*27,a0
	jsr		load_prepare
	mk_a6_addr	d2
	move.l		#0x4006,d3
	jsr		print_hex_preped

	/* handle input */
	jsr		get_input		/* x0cbrldu x1sa00du */

	btst.l		#16+4,d0		/* A - scroll modifier */
	beq		input_noa

	do_dpad		16+0,  sub, #0x0800
	do_dpad		16+1,  add, #0x0800
	do_dpad		16+10, sub, #0xd800
	do_dpad		16+11, add, #0xd800
input_noa:
	moveq.l		#0,d1
	move.w		d7,d1
	lsr.w		#7,d1
	lsr.w		#7,d1

	do_dpad		0,  subq, #0x0008
	do_dpad		1,  addq, #0x0008
	do_dpad		10, sub, d1
	do_dpad		11, add, d1

dpad_end:
	/* update addr */
	move.l		a6,d1
	cmp.b		#0xf0,d1
	blo		0f
	sub.l		#0xd800,a6
	add.w		#0x00d8,a6
	bra		1f
0:
	cmp.b		#0xd8,d1
	blo		1f
	add.l		#0xd800,a6
	sub.w		#0x00d8,a6
1:

	/* other btns */
	moveq.l		#0,d1
	btst.l		#12,d0			/* B - switch byte/word mode */
	beq		input_nob
	bclr.l		#15,d7
	add.w		#0x4000,d7		/* changes between 01 10 */
	move.l		a6,d1
	and.l		#1,d1
	sub.l		d1,a6			/* make even, just in case */

input_nob:
	btst.l		#13,d0			/* C - edit selected byte */
	beq		input_noc

	change_mode	MMODE_EDIT_VAL, MMODE_MAIN
	write_vdp_reg	12,(VDP12_SCREEN_V224 | VDP12_SCREEN_H320 | VDP12_STE)

input_noc:
	btst.l		#5,d0			/* Start - goto */
	beq		input_nos

	change_mode	MMODE_GOTO, MMODE_MAIN
	write_vdp_reg	12,(VDP12_SCREEN_V224 | VDP12_SCREEN_H320 | VDP12_STE)

input_nos:
vbl_end:
	movem.l		(a7)+,d0-d5/a0-a5
	rte


draw_cursor:
	move.l		a6,d0
	and.l		#7,d0		/* byte offs */
	move.l		d0,d1
	lsr.b		#1,d1		/* which word */
	move.b		d1,d2
	lsl.b		#2,d2
	add.b		d2,d1		/* num of chars to skip */
	lsl.b		#1,d1
	move.w		#0x2004,d3

	btst.l		#15,d7
	bne		draw_cursor_word

draw_cursor_byte:
	move.b		(-8,a1,d0),d2
	and.b		#1,d0
	lsl.b		#2,d0
	add.b		d0,d1
	subq.b		#2,d3
	bra		0f

draw_cursor_word:
	move.w		(-8,a1,d0),d2
0:
	lea		(7*2,a2,d1),a0
	jsr		load_prepare
	jsr		print_hex_preped

	move.l		a2,a0
	add.w		#26*2,a0
	jsr		load_prepare	/* restore a0 */

	jmp		draw_chars_pre


#################### hedit #######################

mode_edit_val:
	btst.l		#7,d6
	bne		mode_hedit_finish

	/* read val to edit */
	mk_a6_addr	d1
	move.l		d1,a0
	moveq.l		#0,d0
	btst.l		#15,d7
	bne		0f
	move.b		(a0),d0
	bra		1f
0:
	move.w		(a0),d0
1:
	lsl.l		#8,d0
	and.l		#0xff,d6
	or.l		d0,d6

	and.b		#0x0f,d6	/* not done, reset pos */
	change_mode	MMODE_VAL_INPUT, MMODE_EDIT_VAL
	jmp		vbl_end

mode_hedit_finish:
	/* write the val */
	mk_a6_addr	d1
	move.l		d1,a0
	move.l		d6,d0
	lsr.l		#8,d0

	btst.l		#15,d7
	bne		0f
	move.b		d0,(a0)
	bra		1f
0:
	move.w		d0,(a0)
1:

	and.l		#0xf,d6		/* forget val and pos */
	bra		return_to_main

##################### goto #######################

mode_goto:
	btst.l		#7,d6
	bne		mode_goto_finish

	or.w		#0xc000,d7	/* 3 bytes */
	bclr.l		#7,d6
	change_mode	MMODE_VAL_INPUT, MMODE_GOTO
	jmp		vbl_end

mode_goto_finish:
	move.l		d6,d0
	lsr.l		#8,d0
	move.l		d0,d1
	and.l		#7,d1
	and.b		#0xf8,d0
	lsl.l		#8,d0
	or.l		d1,d0
	move.l		d0,a6

	and.w		#0x3fff,d7
	or.w		#0x8000,d7	/* back to 2 bytes */
	bra		return_to_main

################### val edit #####################

mode_val_input:
	/* frame */
	movea.l		#0xe000+14*2+11*64*2,a1
	moveq.l		#6-1,d1
0:
	move.w		a1,a0
	jsr		load_prepare
	moveq.l		#11-1,d0
1:
	move.w		#0,(a0)
	dbra		d0,1b

	add.w		#64*2,a1
	dbra		d1,0b

	/* text */
	lea		txt_edit,a0
	move.l		#15,d0
	move.l		#11,d1
	move.l		#0xc000,d2
	jsr		print

	lea		txt_a_confirm,a0
	move.l		#15,d0
	move.l		#15,d1
	move.l		#0xc000,d2
	jsr		print

	/* edit field */
	moveq.l		#0,d0
	moveq.l		#0,d1
	moveq.l		#0,d3
	move.w		d7,d3
	lsr.w		#7,d3
	lsr.w		#7,d3

	move.b		#19,d0
	sub.b		d3,d0
	move.b		#13,d1
	move.l		d6,d2
	lsr.l		#8,d2
	add.b		d3,d3
	or.w		#0x8000,d3
	jsr		print_hex

	/* current char */
	moveq.l		#0,d0
	moveq.l		#0,d1

	and.w		#6,d3
	move.b		#19,d0
	move.b		d3,d1
	lsr.b		#1,d1		/* length in bytes */
	sub.b		d1,d0
	move.b		d6,d1
	lsr.b		#4,d1
	and.b		#7,d1		/* nibble to edit */
	add.b		d1,d0

	sub.b		d1,d3
	sub.b		#1,d3		/* chars to shift out */
	lsl.b		#2,d3
	add.b		#8,d3
	move.l		d6,d2
	lsr.l		d3,d2

	move.b		#13,d1
	move.w		#0xa001,d3
	jsr		print_hex

	/* handle input */
	jsr		get_input	/* x0cbrldu x1sa00du */

	move.w		d0,d1
	and.w		#0x0f00,d1
	beq		ai_no_dpad
	move.w		d7,d1
	lsr.w		#7,d1
	lsr.w		#7,d1
	add.b		d1,d1		/* nibble count */
	sub.b		#1,d1		/* max n.t.e. val */
	move.b		d6,d2
	lsr.b		#4,d2
	and.b		#7,d2		/* nibble to edit */

	move.b		d0,d3
	and.b		#3,d3
	beq		ai_no_ud
	moveq.l		#0,d3
	moveq.l		#0,d4
	move.b		#0xf,d3
	move.b		#0x1,d4
	sub.b		d2,d1
	lsl.b		#2,d1
	add.b		#8,d1
	lsl.l		d1,d3		/* mask */
	lsl.l		d1,d4		/* what to add/sub */
	move.l		d6,d1
	and.l		d3,d1
	btst.l		#8,d0
	beq		0f
	add.l		d4,d1
	bra		1f
0:
	sub.l		d4,d1
1:
	and.l		d3,d1
	eor.l		#0xffffffff,d3
	and.l		d3,d6
	or.l		d1,d6
	jmp		vbl_end

ai_no_ud:
	btst.l		#10,d0
	bne		0f
	add.b		#1,d2
	bra		1f
0:
	sub.b		#1,d2
1:
	cmp.b		#0,d2
	bge		0f
	move.b		d1,d2
0:
	cmp.b		d1,d2
	ble		0f
	move.b		#0,d2
0:
	and.b		#0x8f,d6
	lsl.b		#4,d2
	or.b		d2,d6
	jmp		vbl_end

ai_no_dpad:
	move.w		d0,d1
	and.w		#0x1020,d1
	beq		ai_no_sb

	and.l		#0xf,d6		/* forget val and pos */
	bra		return_to_main

ai_no_sb:
	btst.l		#4,d0
	beq		ai_no_input
	bset.l		#7,d6
	move.w		d7,d1
	and.w		#0x3800,d1
	lsr.w		#3,d1
	and.w		#0xc0ff,d7
	or.w		d1,d7

ai_no_input:
	jmp		vbl_end


# go back to main mode
return_to_main:
	bclr.l		#7,d6
	change_mode	MMODE_MAIN, MMODE_MAIN
	write_vdp_reg	12,(VDP12_SCREEN_V224 | VDP12_SCREEN_H320)
	jmp		vbl_end


#################################################
#                                               #
#         Initialize VDP registers              #
#                                               #
#################################################

init_gfx:
	move.l 		#GFXCNTL,a3
	write_vdp_reg 	0,(VDP0_E_DISPLAY | VDP0_PLTT_FULL)
	write_vdp_reg 	1,(VDP1_E_VBI | VDP1_E_DISPLAY | VDP1_E_DMA | VDP1_RESERVED)
	write_vdp_reg 	2,(0xe000 >> 10)	/* Screen map a adress */
	write_vdp_reg 	3,(0xe000 >> 10)	/* Window address */
	write_vdp_reg 	4,(0xc000 >> 13)	/* Screen map b address */
	write_vdp_reg 	5,(0xfc00 >>  9)	/* Sprite address */
	write_vdp_reg 	6,0	
	write_vdp_reg	7,0			/* Backdrop color */
	write_vdp_reg	10,1			/* Lines per hblank interrupt */
	write_vdp_reg	11,0			/* 2-cell vertical scrolling */
	write_vdp_reg	12,(VDP12_SCREEN_V224 | VDP12_SCREEN_H320)
	write_vdp_reg	13,(0x8000 >> 10)	/* Horizontal scroll address */
	write_vdp_reg	15,2
	write_vdp_reg	16,(VDP16_MAP_V32 | VDP16_MAP_H64)	/* layer size */
	write_vdp_reg	17,0
	write_vdp_reg	18,0xff
	rts


# read single phase from controller
#  #a0 - addr
#  d0 - result
#  destroys d1,d2
get_input:
	move.b		#0x40,(0xa10003)
	nop
	nop
	nop
	move.b		(0xa10003),d0
	move.b		#0x00,(0xa10003)
	lsl.w		#8,d0
	nop
	move.b		(0xa10003),d0
	eor.w		#0xffff,d0

	swap		d7
	move.w		d7,d1
	eor.w		d0,d1		/* changed btns */
	move.w		d0,d7		/* old val */
	swap		d7
	and.w		d0,d1		/* what changed now */
	bne		0f

	addq.b		#1,d6
	move.b		d6,d2
	and.b		#7,d2		/* do autorepeat every 8 frames */
	cmp.b		#7,d2
	bne		1f
	move.w		d0,d1
0:
	and.b		#0xf8,d6
1:
	swap		d0
	move.w		d1,d0
	rts

# Load tile data from ROM
#  a0: VRAM base
#  a1: pattern address
#  d0: number of tiles to load
#  destroys d1

load_tiles:
	move.l		d0,d1
	VRAM_ADDR_var 	a0
	move.l 		d0,(GFXCNTL).l
	
	move.l 		#GFXDATA,a0
	lsl.w		#3,d1
	subq.l 		#1,d1
0:
	move.l 		(a1)+,(a0)
	dbra 		d1,0b

	rts


# Prepare to write to VDP RAM @a0
# sets a0 to VDP data port for convenience
#  a0: VRAM base
#  destroys d0

load_prepare:
	VRAM_ADDR_var 	a0
	move.l 		d0,(GFXCNTL).l
	move.l 		#GFXDATA,a0
	rts


# Load color data from ROM
#  a0: CRAM base
#  a1: color list address
#  d0: number of colors to load
#  destroys d1

load_colors:
	move.l		d0,d1
	CRAM_ADDR_var 	a0
	move.l 		d0,(GFXCNTL).l

	move.l 		#GFXDATA,a0
	subq.w		#1,d1
0:
	move.w		(a1)+,(a0)
	dbra		d1,0b

	rts


# print
#  a0 - string
#  d0 - x
#  d1 - y 
#  d2 - tile_bits[15:11]
#  destroys a1

print:
	move.l		a0,a1
	XY2NT
	jsr		load_prepare
	move.l		d2,d0
	and.w		#0xf800,d0

_print_loop:
	move.b		(a1)+,d0
	beq		_print_end

	move.w		d0,(a0)
	jmp		_print_loop

_print_end:
	rts


# print_hex
#  d0 - x
#  d1 - y 
#  d2 - value
#  d3 - digit_cnt[0:7]|tile_bits[11:15]
#  destroys a0, preserves d3

print_hex:
	XY2NT
	jsr		load_prepare

print_hex_preped:
	moveq.l		#0,d0
	move.b		d3,d0
	move.l		d0,d1
	lsl.b		#2,d0
	ror.l		d0,d2		/* prep value */
	subq.l		#1,d1		/* count */
	move.w		d3,d0
	and.w		#0xf800,d0	/* keep upper bits in d0 */

_print_hex_loop:
	rol.l		#4,d2
	move.b		d2,d0
	and.b		#0xf,d0

	add.b		#'0',d0
	cmp.b		#'9',d0
	ble		0f
	addq.b		#7,d0
0:
	move.w		d0,(a0)
	dbra		d1,_print_hex_loop

	rts


#################################################
#                                               #
#       Wait for next VBlank interrupt          #
#                                               #
#################################################

wait_vsync:
	move.b		d7,d0
_wait_change:
	stop		#0x2000
	cmp.b		d7,d0
	beq		_wait_change
	rts


#################################################
#                                               #
#                 RAM DATA                      #
#                                               #
#################################################

.bss

# nothing :)

.end

# vim:filetype=asmM68k
Commit	Line	Data
4db6e09f	1	##################################################
	2	# #
	3	# Assemble with gas #
	4	# --register-prefix-optional --bitwise-or #
	5	# #
	6	##################################################
	7
	8	.text
	9	.globl main
1286a1ba	10	.globl VBL
4db6e09f	11
	12	##################################################
	13	# #
	14	# Register and bitmask definitions #
	15	# #
	16	##################################################
	17
	18	.equ GFXDATA, 0xc00000
	19	.equ GFXCNTL, 0xc00004
	20
	21	.equ VDP0_E_HBI, 0x10
	22	.equ VDP0_E_DISPLAY, 0x02
	23	.equ VDP0_PLTT_FULL, 0x04
	24
	25	.equ VDP1_SMS_MODE, 0x80
	26	.equ VDP1_E_DISPLAY, 0x40
	27	.equ VDP1_E_VBI, 0x20
	28	.equ VDP1_E_DMA, 0x10
	29	.equ VDP1_NTSC, 0x00
	30	.equ VDP1_PAL, 0x08
	31	.equ VDP1_RESERVED, 0x04
	32
fbad1b76	33	.equ VDP12_STE, 0x08
4db6e09f	34	.equ VDP12_SCREEN_V224, 0x00
	35	.equ VDP12_SCREEN_V448, 0x04
	36	.equ VDP12_PROGRESSIVE, 0x00
	37	.equ VDP12_INTERLACED, 0x02
	38	.equ VDP12_SCREEN_H256, 0x00
	39	.equ VDP12_SCREEN_H320, 0x81
	40
	41	.equ VDP16_MAP_V32, 0x00
	42	.equ VDP16_MAP_V64, 0x10
	43	.equ VDP16_MAP_V128, 0x30
	44	.equ VDP16_MAP_H32, 0x00
	45	.equ VDP16_MAP_H64, 0x01
	46	.equ VDP16_MAP_H128, 0x03
	47
4dfddc2f	48	.equ MMODE_MAIN, 0
	49	.equ MMODE_VAL_INPUT, 1
	50	.equ MMODE_EDIT_VAL, 2
	51	.equ MMODE_GOTO, 3
4db6e09f	52
	53
	54	##################################################
	55	# #
	56	# MACROS #
	57	# #
	58	##################################################
	59
	60
	61	/* Write val to VDP register reg */
	62	.macro write_vdp_reg reg val
	63	move.w #((\reg << 8) + 0x8000 + \val),(a3)
	64	.endm
	65
	66
	67	/* For immediate addresses */
	68	.macro VRAM_ADDR reg adr
	69	move.l #(((0x4000 + (\adr & 0x3fff)) << 16) + (\adr >> 14)),\reg
	70	.endm
	71
	72
0fc4f06b	73	.macro CRAM_ADDR reg adr
	74	move.l #(((0xc000 + (\adr & 0x3fff)) << 16) + (\adr >> 14)),\reg
	75	.endm
	76
	77
	78	# make VDP word from address adr and store in d0
	79	.macro XRAM_ADDR_var adr
570c4371	80	move.l \adr,d0
0fc4f06b	81	lsl.l #8,d0
	82	lsl.l #8,d0
	83	rol.l #2,d0
	84	lsl.b #2,d0
	85	lsr.l #2,d0
4db6e09f	86	.endm
	87
	88
0fc4f06b	89	.macro VRAM_ADDR_var adr
	90	XRAM_ADDR_var \adr
	91	or.l #0x40000000,d0
4db6e09f	92	.endm
	93
	94
0fc4f06b	95	.macro CRAM_ADDR_var adr
	96	XRAM_ADDR_var \adr
	97	or.l #0xc0000000,d0
4db6e09f	98	.endm
	99
	100
	101	.macro VSCROLL_ADDR reg adr
	102	move.l #(((0x4000 + (\adr & 0x3fff)) << 16) + ((\adr >> 14) \| 0x10)),\reg
	103	.endm
	104
	105
	106	.macro HSCROLL_ADDR reg adr
	107	move.l #(((0x4000 + (\adr & 0x3fff)) << 16) + (\adr >> 14)),\reg
	108	.endm
	109
	110
1286a1ba	111	# convert tile coords in d0, d1 to nametable addr to a0
	112	.macro XY2NT
	113	lsl.w #6,d1
	114	add.w d1,d0
	115	lsl.w #1,d0
	116	movea.l #0xe000,a0
	117	add.w d0,a0
	118	.endm
	119
4276cd7a	120	# check if some d-pad button (and modifier) is pressed
fbad1b76	121	.macro do_dpad bit op val
	122	btst.l #\bit,d0
	123	beq 0f
	124	\op.l \val,a6
	125	bra dpad_end
4276cd7a	126	0:
4276cd7a	127	.endm
4276cd7a	128
4dfddc2f	129	# convert a6 to normal addr
	130	# destroys d0
	131	.macro mk_a6_addr reg
	132	move.l a6,\reg
	133	moveq.l #0,d0
	134	move.b \reg,d0
	135	lsr.l #8,\reg
	136	add.l d0,\reg
	137	.endm
	138
	139	.macro change_mode mode_new mode_back
	140	and.w #0xc0ff,d7
	141	or.w #(\mode_back<<11)\|(\mode_new<<8),d7
	142	.endm
	143
4db6e09f	144	#################################################
	145	# #
	146	# DATA #
	147	# #
	148	#################################################
	149
	150	colors:
4276cd7a	151	dc.w 0x0000,0x0eee,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000
	152	dc.w 0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000
	153	dc.w 0x0000,0x02e2,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000
	154	dc.w 0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000
	155	dc.w 0x0000,0x0e44,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000
	156	dc.w 0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000
570c4371	157	colors_end:
570c4371	158
4db6e09f	159
	160	sprite_data:
	161	/* Y size link attr X */
570c4371	162	dc.w 0; dc.b 0x05; dc.b 0; dc.w 0x6002; dc.w 0
4db6e09f	163	sprite_data_end:
4db6e09f	164
4dfddc2f	165	txt_edit:
	166	.ascii "- edit -\0"
	167	txt_a_confirm:
	168	.ascii "A-confirm\0"
	169
4db6e09f	170	##################################################
	171	# #
	172	# MAIN PROGRAM #
	173	# #
	174	##################################################
	175
570c4371	176	.align 2
570c4371	177
4db6e09f	178	main:
4276cd7a	179	/* mask irqs during init */
1286a1ba	180	move.w #0x2700,sr
	181
	182	movea.l #0,a6
4dfddc2f	183	move.l #0x8000,d7
fbad1b76	184	moveq.l #0,d6
1286a1ba	185
	186	/* Init pads */
	187	move.b #0x40,(0xa10009).l
	188	move.b #0x40,(0xa10003).l
	189
4db6e09f	190	/* Initialize VDP */
	191	jsr init_gfx
	192
	193	/* Load color data */
0fc4f06b	194	movea.l #0,a0
	195	movea.l #colors,a1
	196	moveq.l #(colors_end-colors)/2,d0
4db6e09f	197	jsr load_colors
	198
	199	/* load patterns */
0fc4f06b	200	movea.l #0,a0
	201	movea.l #font,a1
	202	move.l #128,d0
4db6e09f	203	jsr load_tiles
	204
	205	/* generate A layer map */
1286a1ba	206	movea.l #0xe000,a1
4db6e09f	207	move.l #28-1,d4
4db6e09f	208	lmaploop0:
1286a1ba	209	movea.l a1,a0
4db6e09f	210	jsr load_prepare
4db6e09f	211
570c4371	212	move.l #64/2-1,d3
0fc4f06b	213	0: move.l #0x00000000,(a0)
4db6e09f	214	dbra d3,0b
4db6e09f	215
1286a1ba	216	add.l #64*2,a1
4db6e09f	217	dbra d4,lmaploop0
	218
	219	/* generate B layer map */
0fc4f06b	220	movea.l #0xc000,a0
4db6e09f	221	jsr load_prepare
4db6e09f	222
570c4371	223	move.l #64*28/2-1,d3
0fc4f06b	224	0: move.l #0x00000000,(a0)
4db6e09f	225	dbra d3,0b
	226
	227	/* upload sprite data */
0fc4f06b	228	movea.l #0xfc00,a0
4db6e09f	229	jsr load_prepare
0fc4f06b	230	movea.l #sprite_data,a1
4db6e09f	231
4db6e09f	232	move.l #(sprite_data_end-sprite_data)/2-1,d3
0fc4f06b	233	0: move.l (a1)+,(a0)
4db6e09f	234	dbra d3,0b
4db6e09f	235
1286a1ba	236	move.w #0x2000,sr
570c4371	237
4db6e09f	238	##################################################
	239	# #
	240	# MAIN LOOP #
	241	# #
	242	##################################################
	243
1286a1ba	244	# global regs:
fbad1b76	245	# a6 = page_start[31:8]\|cursor_offs[7:0]
4dfddc2f	246	# d7 = old_inputs[31:16]\|edit_bytes[15:14]\|g_mode_old[13:11]\|g_mode[10:8]\|irq_cnt[7:0]
4dfddc2f	247	# d6 = edit_word[31:8]\|edit_done[7]\|edit_pos[6:4]\|autorep_cnt[3:0]
1286a1ba	248
4db6e09f	249	forever:
4db6e09f	250
4db6e09f	251
	252	jsr wait_vsync
	253	bra forever
	254
	255
	256
1286a1ba	257	VBL:
fbad1b76	258	addq.b #1,d7
fbad1b76	259	movem.l d0-d5/a0-a5,-(a7)
1286a1ba	260
fbad1b76	261	moveq.l #0,d0
	262	move.w d7,d0
	263	lsr.w #6,d0
	264	and.w #0x1c,d0
	265	move.l (jumptab,pc,d0),a0
	266	jmp (a0)
	267	jumptab:
	268	dc.l mode_main
4dfddc2f	269	dc.l mode_val_input
	270	dc.l mode_edit_val /* edit val in editor */
	271	dc.l mode_goto
fbad1b76	272	dc.l mode_main
	273	dc.l mode_main
	274	dc.l mode_main
	275	dc.l mode_main
	276
	277	##################### main #######################
	278
	279	mode_main:
4276cd7a	280	clr.l d1
1286a1ba	281	move.l a6,d0
4276cd7a	282	move.b d0,d1
1286a1ba	283	lsr.l #8,d0
1286a1ba	284	move.l d0,a1 /* current addr */
4276cd7a	285	lsr.b #3,d1
	286	neg.b d1
	287	add.b #27-1,d1 /* line where the cursor sits */
	288	swap d1
1286a1ba	289
1286a1ba	290	movea.l #0xe004,a2
4276cd7a	291	move.l #27-1,d5 /* line counter for dbra */
4276cd7a	292	or.l d1,d5
1286a1ba	293
	294	draw_column:
	295	move.l a2,a0
	296	jsr load_prepare
	297
	298	/* addr */
	299	move.l a1,d2
	300	moveq.l #6,d3
	301	jsr print_hex_preped
	302
	303	/* 4 shorts */
4276cd7a	304	moveq.l #4,d3
1286a1ba	305	moveq.l #4-1,d4
	306	draw_shorts:
	307	move.w #' ',(a0)
	308	move.w (a1)+,d2
1286a1ba	309	jsr print_hex_preped
	310	dbra d4,draw_shorts
	311
4276cd7a	312	move.l d5,d0
	313	swap d0
	314	cmp.w d5,d0
	315	beq draw_cursor
	316
	317	draw_chars_pre:
	318	move.l #(' '<<16)\|' ',(a0)
1286a1ba	319
	320	/* 8 chars */
	321	subq.l #8,a1
	322	moveq.l #8-1,d4
	323	draw_chars:
	324	move.b (a1)+,d0
	325	move.b d0,d1
	326	sub.b #0x20,d1
	327	cmp.b #0x60,d1
	328	blo 0f
	329	move.w #'.',d0
	330	0:
	331	move.w d0,(a0)
	332	dbra d4,draw_chars
	333
	334	add.w #0x80,a2
	335	dbra d5,draw_column
	336
4276cd7a	337	/* status bar */
	338	movea.l #0xe004+64227,a0
	339	jsr load_prepare
4dfddc2f	340	mk_a6_addr d2
4276cd7a	341	move.l #0x4006,d3
	342	jsr print_hex_preped
	343
1286a1ba	344	/* handle input */
1286a1ba	345	jsr get_input /* x0cbrldu x1sa00du */
1286a1ba	346
fbad1b76	347	btst.l #16+4,d0 /* A - scroll modifier */
	348	beq input_noa
	349
	350	do_dpad 16+0, sub, #0x0800
	351	do_dpad 16+1, add, #0x0800
	352	do_dpad 16+10, sub, #0xd800
	353	do_dpad 16+11, add, #0xd800
	354	input_noa:
	355	moveq.l #0,d1
4dfddc2f	356	move.w d7,d1
	357	lsr.w #7,d1
	358	lsr.w #7,d1
fbad1b76	359
	360	do_dpad 0, subq, #0x0008
	361	do_dpad 1, addq, #0x0008
	362	do_dpad 10, sub, d1
	363	do_dpad 11, add, d1
	364
	365	dpad_end:
4dfddc2f	366	/* update addr */
	367	move.l a6,d1
	368	cmp.b #0xf0,d1
	369	blo 0f
	370	sub.l #0xd800,a6
	371	add.w #0x00d8,a6
	372	bra 1f
	373	0:
	374	cmp.b #0xd8,d1
	375	blo 1f
	376	add.l #0xd800,a6
	377	sub.w #0x00d8,a6
	378	1:
	379
	380	/* other btns */
fbad1b76	381	moveq.l #0,d1
	382	btst.l #12,d0 /* B - switch byte/word mode */
	383	beq input_nob
4dfddc2f	384	bclr.l #15,d7
4dfddc2f	385	add.w #0x4000,d7 /* changes between 01 10 */
fbad1b76	386	move.l a6,d1
	387	and.l #1,d1
	388	sub.l d1,a6 /* make even, just in case */
	389
	390	input_nob:
	391	btst.l #13,d0 /* C - edit selected byte */
	392	beq input_noc
4dfddc2f	393
4dfddc2f	394	change_mode MMODE_EDIT_VAL, MMODE_MAIN
fbad1b76	395	write_vdp_reg 12,(VDP12_SCREEN_V224 \| VDP12_SCREEN_H320 \| VDP12_STE)
	396
	397	input_noc:
4dfddc2f	398	btst.l #5,d0 /* Start - goto */
	399	beq input_nos
	400
	401	change_mode MMODE_GOTO, MMODE_MAIN
	402	write_vdp_reg 12,(VDP12_SCREEN_V224 \| VDP12_SCREEN_H320 \| VDP12_STE)
1286a1ba	403
4dfddc2f	404	input_nos:
fbad1b76	405	vbl_end:
fbad1b76	406	movem.l (a7)+,d0-d5/a0-a5
1286a1ba	407	rte
	408
	409
4276cd7a	410	draw_cursor:
	411	move.l a6,d0
	412	and.l #7,d0 /* byte offs */
	413	move.l d0,d1
	414	lsr.b #1,d1 /* which word */
	415	move.b d1,d2
	416	lsl.b #2,d2
	417	add.b d2,d1 /* num of chars to skip */
	418	lsl.b #1,d1
fbad1b76	419	move.w #0x2004,d3
4276cd7a	420
fbad1b76	421	btst.l #15,d7
4dfddc2f	422	bne draw_cursor_word
4276cd7a	423
fbad1b76	424	draw_cursor_byte:
	425	move.b (-8,a1,d0),d2
	426	and.b #1,d0
	427	lsl.b #2,d0
	428	add.b d0,d1
	429	subq.b #2,d3
	430	bra 0f
	431
	432	draw_cursor_word:
	433	move.w (-8,a1,d0),d2
	434	0:
4276cd7a	435	lea (7*2,a2,d1),a0
4276cd7a	436	jsr load_prepare
4276cd7a	437	jsr print_hex_preped
	438
	439	move.l a2,a0
	440	add.w #26*2,a0
	441	jsr load_prepare /* restore a0 */
	442
	443	jmp draw_chars_pre
	444
	445
4dfddc2f	446	#################### hedit #######################
	447
	448	mode_edit_val:
	449	btst.l #7,d6
	450	bne mode_hedit_finish
	451
	452	/* read val to edit */
	453	mk_a6_addr d1
	454	move.l d1,a0
	455	moveq.l #0,d0
	456	btst.l #15,d7
	457	bne 0f
	458	move.b (a0),d0
	459	bra 1f
	460	0:
	461	move.w (a0),d0
	462	1:
	463	lsl.l #8,d0
	464	and.l #0xff,d6
	465	or.l d0,d6
	466
	467	and.b #0x0f,d6 /* not done, reset pos */
	468	change_mode MMODE_VAL_INPUT, MMODE_EDIT_VAL
	469	jmp vbl_end
	470
	471	mode_hedit_finish:
	472	/* write the val */
	473	mk_a6_addr d1
	474	move.l d1,a0
	475	move.l d6,d0
	476	lsr.l #8,d0
	477
	478	btst.l #15,d7
	479	bne 0f
	480	move.b d0,(a0)
	481	bra 1f
	482	0:
	483	move.w d0,(a0)
	484	1:
	485
	486	and.l #0xf,d6 /* forget val and pos */
	487	bra return_to_main
	488
	489	##################### goto #######################
	490
	491	mode_goto:
	492	btst.l #7,d6
	493	bne mode_goto_finish
fbad1b76	494
4dfddc2f	495	or.w #0xc000,d7 /* 3 bytes */
	496	bclr.l #7,d6
	497	change_mode MMODE_VAL_INPUT, MMODE_GOTO
	498	jmp vbl_end
	499
	500	mode_goto_finish:
	501	move.l d6,d0
	502	lsr.l #8,d0
	503	move.l d0,d1
	504	and.l #7,d1
	505	and.b #0xf8,d0
	506	lsl.l #8,d0
	507	or.l d1,d0
	508	move.l d0,a6
	509
	510	and.w #0x3fff,d7
	511	or.w #0x8000,d7 /* back to 2 bytes */
	512	bra return_to_main
	513
	514	################### val edit #####################
	515
	516	mode_val_input:
	517	/* frame */
	518	movea.l #0xe000+142+1164*2,a1
	519	moveq.l #6-1,d1
	520	0:
	521	move.w a1,a0
	522	jsr load_prepare
	523	moveq.l #11-1,d0
	524	1:
	525	move.w #0,(a0)
	526	dbra d0,1b
	527
	528	add.w #64*2,a1
	529	dbra d1,0b
	530
	531	/* text */
	532	lea txt_edit,a0
	533	move.l #15,d0
	534	move.l #11,d1
	535	move.l #0xc000,d2
	536	jsr print
	537
	538	lea txt_a_confirm,a0
	539	move.l #15,d0
	540	move.l #15,d1
	541	move.l #0xc000,d2
	542	jsr print
	543
	544	/* edit field */
	545	moveq.l #0,d0
	546	moveq.l #0,d1
	547	moveq.l #0,d3
	548	move.w d7,d3
	549	lsr.w #7,d3
	550	lsr.w #7,d3
	551
	552	move.b #19,d0
	553	sub.b d3,d0
	554	move.b #13,d1
	555	move.l d6,d2
	556	lsr.l #8,d2
	557	add.b d3,d3
	558	or.w #0x8000,d3
559	jsr print_hex
560
561	/* current char */
562	moveq.l #0,d0
563	moveq.l #0,d1
564
565	and.w #6,d3
566	move.b #19,d0
567	move.b d3,d1
568	lsr.b #1,d1 /* length in bytes */
569	sub.b d1,d0
570	move.b d6,d1
571	lsr.b #4,d1
572	and.b #7,d1 /* nibble to edit */
573	add.b d1,d0
574
575	sub.b d1,d3
576	sub.b #1,d3 /* chars to shift out */
577	lsl.b #2,d3
578	add.b #8,d3
579	move.l d6,d2
580	lsr.l d3,d2
581
582	move.b #13,d1
583	move.w #0xa001,d3
584	jsr print_hex
585
586	/* handle input */
587	jsr get_input /* x0cbrldu x1sa00du */
588
589	move.w d0,d1
590	and.w #0x0f00,d1
591	beq ai_no_dpad
592	move.w d7,d1
593	lsr.w #7,d1
594	lsr.w #7,d1
595	add.b d1,d1 /* nibble count */
596	sub.b #1,d1 /* max n.t.e. val */
597	move.b d6,d2
598	lsr.b #4,d2
599	and.b #7,d2 /* nibble to edit */
600
601	move.b d0,d3
602	and.b #3,d3
603	beq ai_no_ud
604	moveq.l #0,d3
605	moveq.l #0,d4
606	move.b #0xf,d3
607	move.b #0x1,d4
608	sub.b d2,d1
609	lsl.b #2,d1
610	add.b #8,d1
611	lsl.l d1,d3 /* mask */
612	lsl.l d1,d4 /* what to add/sub */
613	move.l d6,d1
614	and.l d3,d1
615	btst.l #8,d0
616	beq 0f
617	add.l d4,d1
618	bra 1f
619	0:
620	sub.l d4,d1
621	1:
622	and.l d3,d1
623	eor.l #0xffffffff,d3
624	and.l d3,d6
625	or.l d1,d6
626	jmp vbl_end
627
628	ai_no_ud:
629	btst.l #10,d0
630	bne 0f
631	add.b #1,d2
632	bra 1f
633	0:
634	sub.b #1,d2
635	1:
636	cmp.b #0,d2
637	bge 0f
638	move.b d1,d2
639	0:
640	cmp.b d1,d2
641	ble 0f
642	move.b #0,d2
643	0:
644	and.b #0x8f,d6
645	lsl.b #4,d2
646	or.b d2,d6
647	jmp vbl_end
648
649	ai_no_dpad:
650	move.w d0,d1
651	and.w #0x1020,d1
652	beq ai_no_sb
653
654	and.l #0xf,d6 /* forget val and pos */
655	bra return_to_main
656
657	ai_no_sb:
658	btst.l #4,d0
659	beq ai_no_input
660	bset.l #7,d6
661	move.w d7,d1
662	and.w #0x3800,d1
663	lsr.w #3,d1
664	and.w #0xc0ff,d7
665	or.w d1,d7
666
667	ai_no_input:
668	jmp vbl_end
669
670
671	# go back to main mode
672	return_to_main:
673	bclr.l #7,d6
674	change_mode MMODE_MAIN, MMODE_MAIN
675	write_vdp_reg 12,(VDP12_SCREEN_V224 \| VDP12_SCREEN_H320)
fbad1b76	676	jmp vbl_end
	677
	678
4db6e09f	679	#################################################
	680	# #
	681	# Initialize VDP registers #
	682	# #
	683	#################################################
	684
	685	init_gfx:
	686	move.l #GFXCNTL,a3
570c4371	687	write_vdp_reg 0,(VDP0_E_DISPLAY \| VDP0_PLTT_FULL)
570c4371	688	write_vdp_reg 1,(VDP1_E_VBI \| VDP1_E_DISPLAY \| VDP1_E_DMA \| VDP1_RESERVED)
4db6e09f	689	write_vdp_reg 2,(0xe000 >> 10) /* Screen map a adress */
	690	write_vdp_reg 3,(0xe000 >> 10) /* Window address */
	691	write_vdp_reg 4,(0xc000 >> 13) /* Screen map b address */
	692	write_vdp_reg 5,(0xfc00 >> 9) /* Sprite address */
	693	write_vdp_reg 6,0
570c4371	694	write_vdp_reg 7,0 /* Backdrop color */
4db6e09f	695	write_vdp_reg 10,1 /* Lines per hblank interrupt */
4db6e09f	696	write_vdp_reg 11,0 /* 2-cell vertical scrolling */
570c4371	697	write_vdp_reg 12,(VDP12_SCREEN_V224 \| VDP12_SCREEN_H320)
570c4371	698	write_vdp_reg 13,(0x8000 >> 10) /* Horizontal scroll address */
4db6e09f	699	write_vdp_reg 15,2
570c4371	700	write_vdp_reg 16,(VDP16_MAP_V32 \| VDP16_MAP_H64) /* layer size */
4db6e09f	701	write_vdp_reg 17,0
	702	write_vdp_reg 18,0xff
	703	rts
	704
	705
1286a1ba	706	# read single phase from controller
fbad1b76	707	# #a0 - addr
1286a1ba	708	# d0 - result
fbad1b76	709	# destroys d1,d2
1286a1ba	710	get_input:
	711	move.b #0x40,(0xa10003)
	712	nop
	713	nop
	714	nop
	715	move.b (0xa10003),d0
	716	move.b #0x00,(0xa10003)
	717	lsl.w #8,d0
	718	nop
	719	move.b (0xa10003),d0
	720	eor.w #0xffff,d0
fbad1b76	721
	722	swap d7
	723	move.w d7,d1
	724	eor.w d0,d1 /* changed btns */
	725	move.w d0,d7 /* old val */
	726	swap d7
	727	and.w d0,d1 /* what changed now */
	728	bne 0f
	729
	730	addq.b #1,d6
	731	move.b d6,d2
	732	and.b #7,d2 /* do autorepeat every 8 frames */
	733	cmp.b #7,d2
	734	bne 1f
	735	move.w d0,d1
	736	0:
	737	and.b #0xf8,d6
	738	1:
	739	swap d0
	740	move.w d1,d0
1286a1ba	741	rts
1286a1ba	742
0fc4f06b	743	# Load tile data from ROM
	744	# a0: VRAM base
	745	# a1: pattern address
	746	# d0: number of tiles to load
	747	# destroys d1
4db6e09f	748
4db6e09f	749	load_tiles:
0fc4f06b	750	move.l d0,d1
	751	VRAM_ADDR_var a0
	752	move.l d0,(GFXCNTL).l
4db6e09f	753
0fc4f06b	754	move.l #GFXDATA,a0
	755	lsl.w #3,d1
	756	subq.l #1,d1
	757	0:
	758	move.l (a1)+,(a0)
	759	dbra d1,0b
4db6e09f	760
	761	rts
	762
	763
4dfddc2f	764	# Prepare to write to VDP RAM @a0
0fc4f06b	765	# sets a0 to VDP data port for convenience
	766	# a0: VRAM base
	767	# destroys d0
570c4371	768
4db6e09f	769	load_prepare:
0fc4f06b	770	VRAM_ADDR_var a0
	771	move.l d0,(GFXCNTL).l
	772	move.l #GFXDATA,a0
4db6e09f	773	rts
	774
	775
0fc4f06b	776	# Load color data from ROM
	777	# a0: CRAM base
	778	# a1: color list address
	779	# d0: number of colors to load
	780	# destroys d1
4db6e09f	781
4db6e09f	782	load_colors:
0fc4f06b	783	move.l d0,d1
	784	CRAM_ADDR_var a0
	785	move.l d0,(GFXCNTL).l
4db6e09f	786
0fc4f06b	787	move.l #GFXDATA,a0
	788	subq.w #1,d1
	789	0:
	790	move.w (a1)+,(a0)
	791	dbra d1,0b
4db6e09f	792
	793	rts
	794
0fc4f06b	795
	796	# print
	797	# a0 - string
	798	# d0 - x
	799	# d1 - y
4dfddc2f	800	# d2 - tile_bits[15:11]
0fc4f06b	801	# destroys a1
570c4371	802
570c4371	803	print:
0fc4f06b	804	move.l a0,a1
1286a1ba	805	XY2NT
0fc4f06b	806	jsr load_prepare
4dfddc2f	807	move.l d2,d0
4dfddc2f	808	and.w #0xf800,d0
570c4371	809
570c4371	810	_print_loop:
0fc4f06b	811	move.b (a1)+,d0
570c4371	812	beq _print_end
570c4371	813
0fc4f06b	814	move.w d0,(a0)
570c4371	815	jmp _print_loop
	816
	817	_print_end:
	818	rts
	819
4db6e09f	820
1286a1ba	821	# print_hex
	822	# d0 - x
	823	# d1 - y
	824	# d2 - value
4276cd7a	825	# d3 - digit_cnt[0:7]\|tile_bits[11:15]
4276cd7a	826	# destroys a0, preserves d3
1286a1ba	827
	828	print_hex:
	829	XY2NT
	830	jsr load_prepare
	831
	832	print_hex_preped:
4276cd7a	833	moveq.l #0,d0
	834	move.b d3,d0
	835	move.l d0,d1
1286a1ba	836	lsl.b #2,d0
1286a1ba	837	ror.l d0,d2 /* prep value */
4276cd7a	838	subq.l #1,d1 /* count */
	839	move.w d3,d0
	840	and.w #0xf800,d0 /* keep upper bits in d0 */
1286a1ba	841
	842	_print_hex_loop:
	843	rol.l #4,d2
	844	move.b d2,d0
	845	and.b #0xf,d0
1286a1ba	846
1286a1ba	847	add.b #'0',d0
4276cd7a	848	cmp.b #'9',d0
	849	ble 0f
	850	addq.b #7,d0
	851	0:
1286a1ba	852	move.w d0,(a0)
4276cd7a	853	dbra d1,_print_hex_loop
1286a1ba	854
	855	rts
	856
	857
4db6e09f	858	#################################################
	859	# #
	860	# Wait for next VBlank interrupt #
	861	# #
	862	#################################################
	863
	864	wait_vsync:
fbad1b76	865	move.b d7,d0
4db6e09f	866	_wait_change:
4db6e09f	867	stop #0x2000
fbad1b76	868	cmp.b d7,d0
4db6e09f	869	beq _wait_change
	870	rts
	871
	872
	873	#################################################
	874	# #
	875	# RAM DATA #
	876	# #
	877	#################################################
	878
	879	.bss
570c4371	880
fbad1b76	881	# nothing :)
4db6e09f	882
	883	.end
	884
	885	# vim:filetype=asmM68k