diff options
| -rw-r--r-- | common.asm | 222 | ||||
| -rw-r--r-- | constants.asm | 5 |
2 files changed, 212 insertions, 15 deletions
@@ -108,8 +108,79 @@ jp Start Section "start",HOME[$150] Start: ; 0x150 + cp $11 ; value that indicates Gameboy Color + jr z,.gbcDetected\@ + xor a + jr .storeValue\@ +.gbcDetected\@ + ld a,$00 +.storeValue\@ + ld [$cf1a],a ; same value ($00) either way + jp InitGame + +; this function directly reads the joypad I/O register +; it reads many times in order to give the joypad a chance to stabilize +; it saves a result in [$fff8] in the following format +; (set bit indicates pressed button) +; bit 0 - A button +; bit 1 - B button +; bit 2 - Select button +; bit 3 - Start button +; bit 4 - Right +; bit 5 - Left +; bit 6 - Up +; bit 7 - Down +ReadJoypadRegister: ; 15F + ld a,%00100000 ; select direction keys + ld c,$00 + ld [rJOYP],a + ld a,[rJOYP] + ld a,[rJOYP] + ld a,[rJOYP] + ld a,[rJOYP] + ld a,[rJOYP] + ld a,[rJOYP] + cpl ; complement the result so that a set bit indicates a pressed key + and a,%00001111 + swap a ; put direction keys in upper nibble + ld b,a + ld a,%00010000 ; select button keys + ld [rJOYP],a + ld a,[rJOYP] + ld a,[rJOYP] + ld a,[rJOYP] + ld a,[rJOYP] + ld a,[rJOYP] + ld a,[rJOYP] + ld a,[rJOYP] + ld a,[rJOYP] + ld a,[rJOYP] + ld a,[rJOYP] + cpl ; complement the result so that a set bit indicates a pressed key + and a,%00001111 + or b ; put button keys in lower nibble + ld [$fff8],a ; save joypad state + ld a,%00110000 ; unselect all keys + ld [rJOYP],a + ret + +; function to update the joypad state variables +; output: +; [$ffb2] = keys released since last time +; [$ffb3] = keys pressed since last time +; [$ffb4] = currently pressed keys +GetJoypadState: ; 19A + ld a, [$ffb8] + push af + ld a,$3 + ld [$ffb8],a + ld [$2000],a + call $4000 + pop af + ld [$ff00+$b8],a + ld [$2000],a + ret -INCBIN "baserom.gbc",$150,$1AE - $150 ; see also MapHeaderBanks MapHeaderPointers: ; $01AE dw PalletTown_h @@ -419,7 +490,7 @@ OverworldLoopLessDelay: ; 402 ld a,[$d736] bit 6,a ; jumping down a ledge? call nz, HandleMidJump - ld a,[$cfc5] ; walking animation counter + ld a,[W_WALKCOUNTER] and a jp nz,.moveAhead\@ ; if the player sprite has not yet completed the walking animation call GetJoypadStateOverworld ; get joypad state (which is possibly simulated) @@ -622,7 +693,7 @@ OverworldLoopLessDelay: ; 402 jp c,OverworldLoop .noCollision\@ ld a,$08 - ld [$cfc5],a ; walking animation counter + ld [W_WALKCOUNTER],a jr .moveAhead2\@ .moveAhead\@ ld a,[$d736] @@ -645,7 +716,7 @@ OverworldLoopLessDelay: ; 402 call BikeSpeedup ; if riding a bike and not jumping a ledge .normalPlayerSpriteAdvancement\@ call AdvancePlayerSprite - ld a,[$cfc5] ; walking animation counter + ld a,[W_WALKCOUNTER] and a jp nz,CheckMapConnections ; it seems like this check will never succeed (the other place where CheckMapConnections is run works) ; walking animation finished @@ -799,7 +870,7 @@ CheckWarpsNoCollisionLoop: ; 6CC jr nz,WarpFound1 push de push bc - call $019a ; update joypad state + call GetJoypadState pop bc pop de ld a,[$ffb4] ; current joypad state @@ -1823,7 +1894,7 @@ AdvancePlayerSprite: ; D27 ld b,a ld a,[$c105] ; delta X ld c,a - ld hl,$cfc5 ; walking animation counter + ld hl,W_WALKCOUNTER ; walking animation counter dec [hl] jr nz,.afterUpdateMapCoords\@ ; if it's the end of the animation, update the player's map coordinates @@ -1834,7 +1905,7 @@ AdvancePlayerSprite: ; D27 add c ld [W_XCOORD],a .afterUpdateMapCoords\@ - ld a,[$cfc5] ; walking animation counter + ld a,[W_WALKCOUNTER] ; walking animation counter cp a,$07 jp nz,.scrollBackgroundAndSprites\@ ; if this is the first iteration of the animation @@ -2205,7 +2276,7 @@ GetJoypadStateOverworld: ; F4D ld [$c103],a ld [$c105],a call RunMapScript - call $019a ; update joypad state + call GetJoypadState ld a,[$d733] bit 3,a ; check if a trainer wants a challenge jr nz,.notForcedDownwards\@ @@ -2698,7 +2769,7 @@ LoadMapData: ; 1241 ld [$d526],a ld [$ffaf],a ld [$ffae],a - ld [$cfc5],a + ld [W_WALKCOUNTER],a ld [$d119],a ld [$d11a],a ld [$d3a8],a @@ -3456,7 +3527,7 @@ TextCommand09: ; 1BFF ; (no arguments) TextCommand0A: ; 1C1D push bc - call $019a ; update joypad state + call GetJoypadState ld a,[$ffb4] and a,%00000011 ; A and B buttons jr nz,.skipDelay\@ @@ -3533,7 +3604,7 @@ TextCommand0C: ; 1C78 ld a,$75 ; ellipsis ld [hli],a push de - call $019a ; update joypad state + call GetJoypadState pop de ld a,[$ffb4] ; joypad state and a,%00000011 ; is A or B button pressed? @@ -3617,7 +3688,128 @@ GetRowColAddressBgMap: ; 1CDD ld h,a ret -INCBIN "baserom.gbc",$1CF0,$20AF - $1CF0 +; clears a VRAM background map with blank space tiles +; INPUT: h - high byte of background tile map address in VRAM +ClearBgMap: ; 1CF0 + ld a,$7f ; blank space + jr .next\@ + ld a,l ; XXX does anything call this? +.next\@ + ld de,$400 ; size of VRAM background map + ld l,e +.loop\@ + ld [hli],a + dec e + jr nz,.loop\@ + dec d + jr nz,.loop\@ + ret + +INCBIN "baserom.gbc",$1D01,$1F54 - $1D01 + +; initialization code +; explanation for %11100011 (value stored in rLCDC) +; * LCD enabled +; * Window tile map at $9C00 +; * Window display enabled +; * BG and window tile data at $8800 +; * BG tile map at $9800 +; * 8x8 OBJ size +; * OBJ display enabled +; * BG display enabled +InitGame: ; 1F54 + di +; zero I/O registers + xor a + ld [$ff0f],a + ld [$ffff],a + ld [$ff43],a + ld [$ff42],a + ld [$ff01],a + ld [$ff02],a + ld [$ff4b],a + ld [$ff4a],a + ld [$ff06],a + ld [$ff07],a + ld [$ff47],a + ld [$ff48],a + ld [$ff49],a + ld a,%10000000 ; enable LCD + ld [rLCDC],a + call DisableLCD ; why enable then disable? + ld sp,$dfff ; initialize stack pointer + ld hl,$c000 ; start of WRAM + ld bc,$2000 ; size of WRAM +.zeroWramLoop\@ + ld [hl],0 + inc hl + dec bc + ld a,b + or c + jr nz,.zeroWramLoop\@ + call ZeroVram + ld hl,$ff80 + ld bc,$007f + call $36e0 ; zero HRAM + call CleanLCD_OAM ; this is unnecessary since it was already cleared above + ld a,$01 + ld [$ffb8],a + ld [$2000],a + call $4bed ; copy DMA code to HRAM + xor a + ld [$ffd7],a + ld [$ff41],a + ld [$ffae],a + ld [$ffaf],a + ld [$ff0f],a + ld a,%00001101 ; enable V-blank, timer, and serial interrupts + ld [rIE],a + ld a,$90 ; put the window off the screen + ld [$ffb0],a + ld [rWX],a + ld a,$07 + ld [rWY],a + ld a,$ff + ld [$ffaa],a + ld h,$98 + call ClearBgMap ; fill $9800-$9BFF (BG tile map) with $7F tiles + ld h,$9c + call ClearBgMap ; fill $9C00-$9FFF (Window tile map) with $7F tiles + ld a,%11100011 + ld [rLCDC],a ; enabled LCD + ld a,$10 + ld [$ff8a],a + call $200e + ei + ld a,$40 + call Predef ; SGB border + ld a,$1f + ld [$c0ef],a + ld [$c0f0],a + ld a,$9c + ld [$ffbd],a + xor a + ld [$ffbc],a + dec a + ld [$cfcb],a + ld a,$32 + call Predef ; display the copyrights, GameFreak logo, and battle animation + call DisableLCD + call ZeroVram + call $3ddc + call CleanLCD_OAM + ld a,%11100011 + ld [rLCDC],a ; enable LCD + jp $42b7 + +; zeroes all VRAM +ZeroVram: ; 2004 + ld hl,$8000 + ld bc,$2000 + xor a + jp $36e0 + +INCBIN "baserom.gbc",$200E,$20AF - $200E DelayFrame: ; 20AF ; delay for one frame @@ -4101,7 +4293,7 @@ DisplayTextID: ; 2920 call $3865 ; wait for a button press after displaying all the text ; loop to hold the dialogue box open as long as the player keeps holding down the A button .holdBoxOpen\@ - call $019a ; update joypad state + call GetJoypadState ld a,[$ffb4] bit 0,a ; is the A button being pressed? jr nz,.holdBoxOpen\@ @@ -5208,7 +5400,7 @@ MainMenu: ; 0x5af2 ld [$FFB3],a ld [$FFB2],a ld [$FFB4],a - call $19A + call GetJoypadState ld a,[$FFB4] bit 0,a jr nz,.next5\@ @@ -5226,7 +5418,7 @@ MainMenu: ; 0x5af2 and a jp z,$5D5F ld a,[W_CURMAP] ; map ID - cp a,$76 ; Hall of Fame + cp a,HALL_OF_FAME jp nz,$5D5F xor a ld [$D71A],a diff --git a/constants.asm b/constants.asm index 4f1df3d0..56301a4b 100644 --- a/constants.asm +++ b/constants.asm @@ -717,10 +717,15 @@ H_RAND2 EQU $FFD4 H_WHOSETURN EQU $FFF3 ; 0 on player’s turn, 1 on enemy’s turn ; hardware registers, from the pandocs http://nocash.emubase.de/pandocs.htm +rJOYP EQU $FF00 rDIV EQU $FF04 +rLCDC EQU $FF40 rBGP EQU $FF47 rOBP0 EQU $FF48 rOBP1 EQU $FF49 +rWX EQU $FF4A +rWY EQU $FF4B +rIE EQU $FFFF ; pokemon name constants |