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1 | ################################################## |
| 2 | # # |
| fce27dd5 |
3 | # Assemble with gas # |
| 4 | # --register-prefix-optional --bitwise-or # |
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5 | # # |
| 6 | ################################################## |
| 7 | |
| 8 | .text |
| 9 | .globl main |
| 10 | |
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11 | ################################################## |
| 12 | # # |
| 13 | # Register and bitmask definitions # |
| 14 | # # |
| 15 | ################################################## |
| 16 | |
| 17 | .equ GFXDATA, 0xc00000 |
| 18 | .equ GFXCNTL, 0xc00004 |
| 19 | |
| 20 | .equ VDP0_E_HBI, 0x10 |
| 21 | .equ VDP0_E_DISPLAY, 0x02 |
| 22 | .equ VDP0_PLTT_FULL, 0x04 |
| 23 | |
| 24 | .equ VDP1_SMS_MODE, 0x80 |
| 25 | .equ VDP1_E_DISPLAY, 0x40 |
| 26 | .equ VDP1_E_VBI, 0x20 |
| 27 | .equ VDP1_E_DMA, 0x10 |
| 28 | .equ VDP1_NTSC, 0x00 |
| 29 | .equ VDP1_PAL, 0x08 |
| 30 | .equ VDP1_RESERVED, 0x04 |
| 31 | |
| 32 | .equ VDP12_SPR_SHADOWS, 0x08 |
| 33 | .equ VDP12_SCREEN_V224, 0x00 |
| 34 | .equ VDP12_SCREEN_V448, 0x04 |
| 35 | .equ VDP12_PROGRESSIVE, 0x00 |
| 36 | .equ VDP12_INTERLACED, 0x02 |
| 37 | .equ VDP12_SCREEN_H256, 0x00 |
| 38 | .equ VDP12_SCREEN_H320, 0x81 |
| 39 | |
| 40 | .equ VDP16_MAP_V32, 0x00 |
| 41 | .equ VDP16_MAP_V64, 0x10 |
| 42 | .equ VDP16_MAP_V128, 0x30 |
| 43 | .equ VDP16_MAP_H32, 0x00 |
| 44 | .equ VDP16_MAP_H64, 0x01 |
| 45 | .equ VDP16_MAP_H128, 0x03 |
| 46 | |
| 47 | |
| 48 | |
| 49 | ################################################## |
| 50 | # # |
| 51 | # MACROS # |
| 52 | # # |
| 53 | ################################################## |
| 54 | |
| 55 | |
| 56 | /* Write val to VDP register reg */ |
| 57 | .macro write_vdp_reg reg val |
| 58 | move.w #((\reg << 8) + 0x8000 + \val),(a3) |
| 59 | .endm |
| 60 | |
| 61 | |
| 62 | /* For immediate addresses */ |
| 63 | .macro VRAM_ADDR reg adr |
| 64 | move.l #(((0x4000 + (\adr & 0x3fff)) << 16) + (\adr >> 14)),\reg |
| 65 | .endm |
| 66 | |
| 67 | |
| 68 | /* For indirect (variable) addresses. |
| 69 | Destroys d6-d7. */ |
| 70 | .macro VRAM_ADDR_var reg adr |
| 71 | move.l \adr,d6 |
| 72 | move.l \adr,d7 |
| 73 | and.w #0x3fff,d6 |
| 74 | lsr.w #7,d7 |
| 75 | lsr.w #7,d7 |
| 76 | add.w #0x4000,d6 |
| 77 | lsl.l #7,d6 |
| 78 | lsl.l #7,d6 |
| 79 | lsl.l #2,d6 |
| 80 | or.l d7,d6 |
| 81 | move.l d6,\reg |
| 82 | .endm |
| 83 | |
| 84 | |
| 85 | .macro CRAM_ADDR reg adr |
| 86 | move.l #(((0xc000 + (\adr & 0x3fff)) << 16) + (\adr >> 14)),\reg |
| 87 | .endm |
| 88 | |
| 89 | |
| 90 | /* For indirect (variable) addresses */ |
| 91 | .macro CRAM_ADDR_var reg adr |
| 92 | move.l \adr,d6 |
| 93 | move.l \adr,d7 |
| 94 | and.w #0x3fff,d6 |
| 95 | lsr.w #7,d7 |
| 96 | lsr.w #7,d7 |
| 97 | add.w #0xc000,d6 |
| 98 | lsl.l #7,d6 |
| 99 | lsl.l #7,d6 |
| 100 | lsl.l #2,d6 |
| 101 | or.l d7,d6 |
| 102 | move.l d6,\reg |
| 103 | .endm |
| 104 | |
| 105 | |
| 106 | .macro VSCROLL_ADDR reg adr |
| 107 | move.l #(((0x4000 + (\adr & 0x3fff)) << 16) + ((\adr >> 14) | 0x10)),\reg |
| 108 | .endm |
| 109 | |
| 110 | |
| 111 | .macro HSCROLL_ADDR reg adr |
| 112 | move.l #(((0x4000 + (\adr & 0x3fff)) << 16) + (\adr >> 14)),\reg |
| 113 | .endm |
| 114 | |
| 115 | |
| fce27dd5 |
116 | ################################################# |
| 117 | # # |
| 118 | # DATA # |
| 119 | # # |
| 120 | ################################################# |
| 121 | |
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122 | colors: |
| 123 | dc.w 0x0040,0x0080,0x000e,0x00e0,0x0e00,0x00ee |
| 124 | pattern: |
| 125 | dc.l 0x00000000,0x00000000,0x00000000,0x00000000,0x00000000,0x00000000,0x00000000,0x00000000 |
| 126 | dc.l 0x22334455,0x22334455,0x22334455,0x22334455,0x22334455,0x22334455,0x22334455,0x22334455 |
| 127 | /* shadow sprite */ |
| 128 | dc.l 0x00000fff |
| 129 | dc.l 0x0000ffff |
| 130 | dc.l 0x00ffffff |
| 131 | dc.l 0x00ffffff |
| 132 | dc.l 0x0fffffff |
| 133 | dc.l 0xffffffff |
| 134 | dc.l 0xffffffff |
| 135 | dc.l 0xffffffff |
| 136 | /* */ |
| 137 | dc.l 0xffffffff |
| 138 | dc.l 0xffffffff |
| 139 | dc.l 0xffffffff |
| 140 | dc.l 0x0fffffff |
| 141 | dc.l 0x00ffffff |
| 142 | dc.l 0x00ffffff |
| 143 | dc.l 0x0000ffff |
| 144 | dc.l 0x00000fff |
| 145 | /* */ |
| 146 | dc.l 0xfff00000 |
| 147 | dc.l 0xffff0000 |
| 148 | dc.l 0xffffff00 |
| 149 | dc.l 0xffffff00 |
| 150 | dc.l 0xfffffff0 |
| 151 | dc.l 0xffffffff |
| 152 | dc.l 0xffffffff |
| 153 | dc.l 0xffffffff |
| 154 | /* */ |
| 155 | dc.l 0xffffffff |
| 156 | dc.l 0xffffffff |
| 157 | dc.l 0xffffffff |
| 158 | dc.l 0xfffffff0 |
| 159 | dc.l 0xffffff00 |
| 160 | dc.l 0xffffff00 |
| 161 | dc.l 0xffff0000 |
| 162 | dc.l 0xfff00000 |
| 163 | /* hilight sprite */ |
| 164 | dc.l 0x00000eee |
| 165 | dc.l 0x0000eeee |
| 166 | dc.l 0x00eeeeee |
| 167 | dc.l 0x00eeeeee |
| 168 | dc.l 0x0eeeeeee |
| 169 | dc.l 0xeeeeeeee |
| 170 | dc.l 0xeeeeeeee |
| 171 | dc.l 0xeeeeeeee |
| 172 | /* */ |
| 173 | dc.l 0xeeeeeeee |
| 174 | dc.l 0xeeeeeeee |
| 175 | dc.l 0xeeeeeeee |
| 176 | dc.l 0x0eeeeeee |
| 177 | dc.l 0x00eeeeee |
| 178 | dc.l 0x00eeeeee |
| 179 | dc.l 0x0000eeee |
| 180 | dc.l 0x00000eee |
| 181 | /* */ |
| 182 | dc.l 0xeee00000 |
| 183 | dc.l 0xeeee0000 |
| 184 | dc.l 0xeeeeee00 |
| 185 | dc.l 0xeeeeee00 |
| 186 | dc.l 0xeeeeeee0 |
| 187 | dc.l 0xeeeeeeee |
| 188 | dc.l 0xeeeeeeee |
| 189 | dc.l 0xeeeeeeee |
| 190 | /* */ |
| 191 | dc.l 0xeeeeeeee |
| 192 | dc.l 0xeeeeeeee |
| 193 | dc.l 0xeeeeeeee |
| 194 | dc.l 0xeeeeeee0 |
| 195 | dc.l 0xeeeeee00 |
| 196 | dc.l 0xeeeeee00 |
| 197 | dc.l 0xeeee0000 |
| 198 | dc.l 0xeee00000 |
| 199 | |
| 200 | |
| 201 | sprite_data: |
| 202 | /* Y size link attr X */ |
| 203 | dc.w 10+128; dc.b 0x05; dc.b 1; dc.w 0x6002; dc.w 0 |
| 204 | dc.w 30+128; dc.b 0x05; dc.b 2; dc.w 0x6006; dc.w 0 |
| 205 | dc.w 60+128; dc.b 0x05; dc.b 3; dc.w 0xe002; dc.w 0 |
| 206 | dc.w 80+128; dc.b 0x05; dc.b 4; dc.w 0xe006; dc.w 0 |
| 207 | dc.w 120+128; dc.b 0x05; dc.b 5; dc.w 0x6002; dc.w 0 |
| 208 | dc.w 140+128; dc.b 0x05; dc.b 6; dc.w 0x6006; dc.w 0 |
| 209 | dc.w 170+128; dc.b 0x05; dc.b 7; dc.w 0xe002; dc.w 0 |
| 210 | dc.w 190+128; dc.b 0x05; dc.b 0; dc.w 0xe006; dc.w 0 |
| 211 | sprite_data_end: |
| 212 | |
| 213 | |
| 214 | ################################################## |
| 215 | # # |
| 216 | # MAIN PROGRAM # |
| 217 | # # |
| 218 | ################################################## |
| 219 | |
| 220 | main: |
| 221 | /* Initialize VDP */ |
| 222 | jsr init_gfx |
| 223 | |
| 224 | /* Load color data */ |
| 225 | movea.l #0,a3 |
| 226 | move.l #colors,a4 |
| 227 | moveq.l #6,d4 |
| 228 | jsr load_colors |
| 229 | |
| 230 | /* load patterns */ |
| 231 | movea.l #0,a3 |
| 232 | movea.l #pattern,a4 |
| 233 | move.l #10,d4 |
| 234 | jsr load_tiles |
| 235 | |
| 236 | /* generate A layer map */ |
| 237 | movea.l #0xe000+10*2,a6 |
| 238 | move.l #28-1,d4 |
| 239 | lmaploop0: |
| 240 | movea.l a6,a3 |
| 241 | jsr load_prepare |
| 242 | |
| 243 | moveq.l #6-1,d3 |
| 244 | 0: move.l #0x00010001,(a3) |
| 245 | dbra d3,0b |
| 246 | |
| 247 | moveq.l #9-1,d3 |
| 248 | 0: move.l #0x80018001,(a3) |
| 249 | dbra d3,0b |
| 250 | |
| 251 | add.l #64*2,a6 |
| 252 | dbra d4,lmaploop0 |
| 253 | |
| 254 | /* generate B layer map */ |
| 255 | movea.l #0xc000+64*14*2,a3 |
| 256 | jsr load_prepare |
| 257 | |
| 258 | move.l #64*14/2-1,d3 |
| 259 | 0: move.l #0x80008000,(a3) |
| 260 | dbra d3,0b |
| 261 | |
| 262 | /* upload sprite data */ |
| 263 | movea.l #0xfc00,a3 |
| 264 | jsr load_prepare |
| 265 | movea.l #sprite_data,a0 |
| 266 | |
| 267 | move.l #(sprite_data_end-sprite_data)/2-1,d3 |
| 268 | 0: move.l (a0)+,(a3) |
| 269 | dbra d3,0b |
| 270 | |
| 271 | jsr wait_vsync |
| 272 | |
| 273 | ################################################## |
| 274 | # # |
| 275 | # MAIN LOOP # |
| 276 | # # |
| 277 | ################################################## |
| 278 | |
| 279 | forever: |
| 280 | movea.l #vtimer,a0 |
| 281 | move.l (a0),d4 |
| 282 | and.w #0x1ff,d4 |
| 283 | movea.l #0xfc06,a6 |
| 284 | moveq.l #8-1,d5 |
| 285 | |
| 286 | 0: |
| 287 | movea.l a6,a3 |
| 288 | jsr load_prepare |
| 289 | move.w d4,(a3) |
| 290 | addq.w #8,a6 |
| 291 | dbra d5,0b |
| 292 | |
| 293 | jsr wait_vsync |
| 294 | bra forever |
| 295 | |
| 296 | |
| 297 | |
| 298 | ################################################# |
| 299 | # # |
| 300 | # Initialize VDP registers # |
| 301 | # # |
| 302 | ################################################# |
| 303 | |
| 304 | init_gfx: |
| 305 | move.l #GFXCNTL,a3 |
| 306 | write_vdp_reg 0,(VDP0_E_DISPLAY + VDP0_PLTT_FULL) |
| 307 | write_vdp_reg 1,(VDP1_E_VBI + VDP1_E_DISPLAY + VDP1_E_DMA + VDP1_RESERVED) |
| 308 | write_vdp_reg 2,(0xe000 >> 10) /* Screen map a adress */ |
| 309 | write_vdp_reg 3,(0xe000 >> 10) /* Window address */ |
| 310 | write_vdp_reg 4,(0xc000 >> 13) /* Screen map b address */ |
| 311 | write_vdp_reg 5,(0xfc00 >> 9) /* Sprite address */ |
| 312 | write_vdp_reg 6,0 |
| 313 | write_vdp_reg 7,1 /* Border color */ |
| 314 | write_vdp_reg 10,1 /* Lines per hblank interrupt */ |
| 315 | write_vdp_reg 11,0 /* 2-cell vertical scrolling */ |
| 316 | write_vdp_reg 12,(VDP12_SCREEN_V224 | VDP12_SCREEN_H320 | VDP12_SPR_SHADOWS) |
| 317 | write_vdp_reg 13,(0x6000 >> 10) /* Horizontal scroll address */ |
| 318 | write_vdp_reg 15,2 |
| 319 | write_vdp_reg 16,(VDP16_MAP_V32 + VDP16_MAP_H64) |
| 320 | write_vdp_reg 17,0 |
| 321 | write_vdp_reg 18,0xff |
| 322 | rts |
| 323 | |
| 324 | |
| 325 | |
| 326 | ################################################# |
| 327 | # # |
| 328 | # Load tile data from ROM # |
| 329 | # # |
| 330 | # Parameters: # |
| 331 | # a3: VRAM base # |
| 332 | # a4: pattern address # |
| 333 | # d4: number of tiles to load # |
| 334 | # Destroys a2,d0,d6-d7... # |
| 335 | # # |
| 336 | ################################################# |
| 337 | |
| 338 | load_tiles: |
| 339 | move.l #GFXCNTL,a2 |
| 340 | VRAM_ADDR_var d0,a3 |
| 341 | move.l d0,(a2) |
| 342 | lsl #3,d4 |
| 343 | |
| 344 | move.l #GFXDATA,a3 |
| 345 | subq.l #1,d4 |
| 346 | _copy_tile_data: |
| 347 | move.l (a4)+,(a3) |
| 348 | dbra d4,_copy_tile_data |
| 349 | |
| 350 | rts |
| 351 | |
| 352 | |
| 353 | load_prepare: |
| 354 | move.l #GFXCNTL,a2 |
| 355 | VRAM_ADDR_var d0,a3 |
| 356 | move.l d0,(a2) |
| 357 | move.l #GFXDATA,a3 |
| 358 | |
| 359 | rts |
| 360 | |
| 361 | |
| 362 | ################################################# |
| 363 | # # |
| 364 | # Clear one of the screen maps # |
| 365 | # # |
| 366 | # Parameters: # |
| 367 | # a0: Map address # |
| 368 | # d0: Data to write to each map entry # |
| 369 | # # |
| 370 | ################################################# |
| 371 | |
| 372 | clear_map: |
| 373 | move.l #GFXCNTL,a4 |
| 374 | VRAM_ADDR_var d1,a0 |
| 375 | move.l d1,(a4) |
| 376 | move.l #GFXDATA,a3 |
| 377 | move.w #1023,d1 /* Loop counter */ |
| 378 | _clear_map_loop: |
| 379 | move.w d0,(a3) |
| 380 | move.w d0,(a3) |
| 381 | dbra d1,_clear_map_loop |
| 382 | rts |
| 383 | |
| 384 | |
| 385 | ################################################# |
| 386 | # # |
| 387 | # Load color data from ROM # |
| 388 | # # |
| 389 | # Parameters: # |
| 390 | # a3: CRAM base # |
| 391 | # a4: color list address # |
| 392 | # d4: number of colors to load # |
| 393 | # # |
| 394 | ################################################# |
| 395 | |
| 396 | load_colors: |
| 397 | move.l #GFXCNTL,a2 |
| 398 | CRAM_ADDR_var d0,a3 |
| 399 | move.l d0,(a2) |
| 400 | |
| 401 | move.l #GFXDATA,a3 |
| 402 | subq.w #1,d4 |
| 403 | _copy_color_data: |
| 404 | move.w (a4)+,(a3) |
| 405 | dbra d4,_copy_color_data |
| 406 | |
| 407 | rts |
| 408 | |
| 409 | |
| 410 | ################################################# |
| 411 | # # |
| 412 | # Wait for next VBlank interrupt # |
| 413 | # # |
| 414 | ################################################# |
| 415 | |
| 416 | wait_vsync: |
| 417 | movea.l #vtimer,a0 |
| 418 | move.l (a0),a1 |
| 419 | _wait_change: |
| 420 | stop #0x2000 |
| 421 | cmp.l (a0),a1 |
| 422 | beq _wait_change |
| 423 | rts |
| 424 | |
| 425 | |
| 426 | ################################################# |
| 427 | # # |
| 428 | # RAM DATA # |
| 429 | # # |
| 430 | ################################################# |
| 431 | |
| 432 | .bss |
| 433 | .globl htimer |
| 434 | .globl vtimer |
| 435 | .globl rand_num |
| 436 | htimer: .long 0 |
| 437 | vtimer: .long 0 |
| 438 | rand_num: .long 0 |
| 439 | scrollx: .long 0 |
| 440 | |
| 441 | .end |
| 442 | |
| fce27dd5 |
443 | # vim:filetype=asmM68k |
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