User:Kmeisthax/Findings/2011/6/6/ROM B 79C1 Disassembly: Difference between revisions
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Latest revision as of 23:11, 8 June 2011
This routine seems to render all the "status screen VWF" text, as opposed to the "main script" text or the "intro scene" text, the latter of which is still not spaced properly.
;A big note: First off, there are a bunch of STATUS BYTES
;that live in Work RAM that control what the VWF does.
;They live at WRAM C7C1 to C7C6, as follows:
; WRAM_Text_CurrentLetter
; WRAM_VWFLetterShift
; WRAM_SPILL_GlyphDrawPtr0
; WRAM_SPILL_GlyphDrawPtr1
; WRAM_Text_OldTileMode
; WRAM_MyMisteryBite
; Theres also a byte at C9CB which I think is also VWF related,
; I named it WRAM_VWFGlyphsToNewline in this disassembly.
ROM:0002F9C1 PhoneNumGetSCR_DrawDenjuuName: ; Routine which draws denjuu name tiles to vram
ROM:0002F9C1 ld a, [WRAM_MyMisteryBite] ; in the "you got a phone number" screen
ROM:0002F9C1 ;
ROM:0002F9C1 ; PARAMS:
ROM:0002F9C1 ; HL - the address of the target VRAM glyph
ROM:0002F9C1 ; DE - the address of the source 1bpp letter
ROM:0002F9C4 cp 1
ROM:0002F9C6 jr nz, loc_2f9d3 ; if the mystery byte is 1, don't move HL back
ROM:0002F9C8 ld a, [WRAM_VWFGlyphsToNewline]
ROM:0002F9CB dec a
ROM:0002F9CC ld [WRAM_VWFGlyphsToNewline], a
ROM:0002F9CF ld bc, $FFF0 ; -F
ROM:0002F9D2 add hl, bc
ROM:0002F9D3
ROM:0002F9D3 loc_2F9D3: ; DATA XREF: ROM:0002F9C6�t
ROM:0002F9D3 ld b, 8
ROM:0002F9D5 ld a, $CF ; '-'
ROM:0002F9D7 ld [WRAM_SPILL_GlyphDrawPtr0], a
ROM:0002F9DA ld a, $D0 ; '-'
ROM:0002F9DC ld [WRAM_SPILL_GlyphDrawPtr1], a ; CFD0 - Appears to be a temporary space for
ROM:0002F9DC ; glyph composing
ROM:0002F9DF
ROM:0002F9DF GlyphDrawLoop: ; DATA XREF: ROM:0002FA40�t
ROM:0002F9DF push bc
ROM:0002F9E0 push de
ROM:0002F9E1 push hl
ROM:0002F9E2 di
ROM:0002F9E3 ld a, [WRAM_SPILL_GlyphDrawPtr0]
ROM:0002F9E6 ld h, a
ROM:0002F9E7 ld a, [WRAM_SPILL_GlyphDrawPtr1] ; HL = 0xCFD0
ROM:0002F9EA ld l, a
ROM:0002F9EB ld b, [hl]
ROM:0002F9EC inc hl
ROM:0002F9ED ld c, [hl] ; BC is the old tile's line that we are
ROM:0002F9ED ; going to superimpose/clear/etc.
ROM:0002F9EE dec hl
ROM:0002F9EF ld a, [de] ; DE is the 1BPP glyph we plan to draw.
ROM:0002F9EF ; It's an input parameter.
ROM:0002F9F0 ld d, a
ROM:0002F9F1 ld e, 0 ; Expand our 1BPP glyph into a 2BPP one
ROM:0002F9F3 ld a, [WRAM_Text_OldTileMode] ; Selects an operation to be performed
ROM:0002F9F3 ; on the existing line before mixing.
ROM:0002F9F6 cp 2
ROM:0002F9F8 jr z, loc_2fa00 ; Mode 2
ROM:0002F9F8 ; This clears the tile.
ROM:0002F9FA cp 1
ROM:0002F9FC jr z, loc_2fa02 ; Mode 1
ROM:0002F9FC ;
ROM:0002F9FC ; This makes the tile black and white
ROM:0002F9FC ; and then superimposes the glyph onto the tile.
ROM:0002F9FC ;
ROM:0002F9FC ; This also is only usually set when we need to move
ROM:0002F9FC ; the glyph frame up.
ROM:0002F9FE jr loc_2fa03 ; Mode 0 (or other modes)
ROM:0002F9FE ; Superimpose the glyph onto the current tile.
ROM:0002F9FE ;
ROM:0002F9FE ; This is set during normal VWF operation, when
ROM:0002F9FE ; we don't need to move to the next tile yet.
ROM:0002FA00 ; ---------------------------------------------------------------------------
ROM:0002FA00
ROM:0002FA00 loc_2FA00: ; DATA XREF: ROM:0002F9F8�t
ROM:0002FA00 ld c, 0
ROM:0002FA02
ROM:0002FA02 loc_2FA02: ; DATA XREF: ROM:0002F9FC�t
ROM:0002FA02 ld b, c
ROM:0002FA03
ROM:0002FA03 loc_2FA03: ; DATA XREF: ROM:0002F9FE�t
ROM:0002FA03 ld a, [WRAM_VWFLetterShift] ; VWF shift value
ROM:0002FA03 ; (verified by tracing the main script)
ROM:0002FA06 or a
ROM:0002FA07 jr z, loc_2fa10
ROM:0002FA09
ROM:0002FA09 loc_2FA09: ; DATA XREF: ROM:0002FA0E�t
ROM:0002FA09 srl d
ROM:0002FA0B rr e
ROM:0002FA0D dec a
ROM:0002FA0E jr nz, loc_2fa09 ; Shift the incoming glyph by the current
ROM:0002FA0E ; letter shift value, if needed.
ROM:0002FA0E ;
ROM:0002FA0E ; It's a right shift for positive values
ROM:0002FA10
ROM:0002FA10 loc_2FA10: ; DATA XREF: ROM:0002FA07�t
ROM:0002FA10 ld a, d
ROM:0002FA11 or b
ROM:0002FA12 ld b, a
ROM:0002FA13 ld c, e ; BC = (B|D) << 8 + E
ROM:0002FA13 ;
ROM:0002FA13 ; Mix the lower bits of the tile,
ROM:0002FA13 ; but overwrite the upper bits.
ROM:0002FA13 ;
ROM:0002FA13 ; E is 0, so this forcibly clears
ROM:0002FA13 ; all upper pallete bits.
ROM:0002FA13 ;
ROM:0002FA13 ; BUG: If we shift a letter, it will
ROM:0002FA13 ; get shifted onto E and that's a problem
ROM:0002FA14 ld [hl], b
ROM:0002FA15 inc hl
ROM:0002FA16 ld [hl], c
ROM:0002FA17 inc hl ; Write into our temporary glyph area.
ROM:0002FA18 ld a, h
ROM:0002FA19 ld [WRAM_SPILL_GlyphDrawPtr0], a
ROM:0002FA1C ld a, l
ROM:0002FA1D ld [WRAM_SPILL_GlyphDrawPtr1], a
ROM:0002FA20 pop hl ; Restore the glyph target address
ROM:0002FA21 ld d, h
ROM:0002FA22 ld e, l
ROM:0002FA23 ld a, [byte_FF41] ; LCD STAT
ROM:0002FA25 and 2
ROM:0002FA27 jr nz, 2fa23 ; loop until it's safe to write
ROM:0002FA29 ld a, b
ROM:0002FA2A ldi [hl], a
ROM:0002FA2B ldi [hl], a ; Now, write into VRAM...
ROM:0002FA2C push hl
ROM:0002FA2D ld hl, $10
ROM:0002FA30 add hl, de
ROM:0002FA31 ld a, [byte_FF41]
ROM:0002FA33 and 2
ROM:0002FA35 jr nz, 2fa31 ; loop until it's safe to write
ROM:0002FA37 ld a, c
ROM:0002FA38 ldi [hl], a
ROM:0002FA39 ldi [hl], a ; Write C into 16 bytes forward on VRAM for some reason
ROM:0002FA39 ; (i.e. the next glyph)
ROM:0002FA3A ei
ROM:0002FA3B pop hl
ROM:0002FA3C pop de
ROM:0002FA3D pop bc
ROM:0002FA3E inc de ; go to the next line
ROM:0002FA3F dec b
ROM:0002FA40 jr nz, GlyphDrawLoop
ROM:0002FA42 ld a, 0
ROM:0002FA44 ld [WRAM_Text_OldTileMode], a
ROM:0002FA47 ld b, $7B ; '{'
ROM:0002FA49 ld a, [WRAM_Text_CurrentLetter]
ROM:0002FA4C ld c, a
ROM:0002FA4D ld a, [bc] ; Letter glyph width table?
ROM:0002FA4D ;
ROM:0002FA4D ; Seems to index 0x2FB00 with the current glyph ID?
ROM:0002FA4E inc a
ROM:0002FA4F ld b, a
ROM:0002FA50 ld a, [WRAM_VWFLetterShift]
ROM:0002FA53 add a, b
ROM:0002FA54 bit 3, a
ROM:0002FA56 jr z, 2FA71 ; following code only execs
ROM:0002FA56 ; on text frame overflow
ROM:0002FA58 sub 8
ROM:0002FA5A push af
ROM:0002FA5B ld a, 1
ROM:0002FA5D ld [WRAM_Text_OldTileMode], a
ROM:0002FA60 ld a, [WRAM_MyMisteryBite]
ROM:0002FA63 cp 1
ROM:0002FA65 jr nz, 2FA6C
ROM:0002FA67 ld a, 0
ROM:0002FA69 ld [WRAM_MyMisteryBite], a ; if the mystery byte is 1, make it 0
ROM:0002FA69 ; some kinda sentinel?
ROM:0002FA6C
ROM:0002FA6C GlyphFinished:
ROM:0002FA6C pop af
ROM:0002FA6D ld [WRAM_VWFLetterShift], a
ROM:0002FA70 ret
ROM:0002FA71 ; ---------------------------------------------------------------------------
ROM:0002FA71 push af
ROM:0002FA72 ld a, [WRAM_VWFGlyphsToNewline]
ROM:0002FA75 cp $10
ROM:0002FA77 jr z, 2FA7F
ROM:0002FA79 dec a
ROM:0002FA7A ld [WRAM_VWFGlyphsToNewline], a
ROM:0002FA7D jr 2FA6C
ROM:0002FA7F ; ---------------------------------------------------------------------------
ROM:0002FA7F ld a, 1
ROM:0002FA81 ld [WRAM_MyMisteryBite], a
ROM:0002FA84 jr 2FA6C