;******************************************************************************
;******************************************************************************
;
;         The almost completely commented C64 BASIC ROM disassembly. 
;                 Based on version V1.01 by Lee Davison 2012
;

;******************************************************************************
;
; start of the kernal ROM
;
; version 390852-01, second part, for the Commodore 64 GS
;


; extra variables for the C64GS
.eq Z_FB		= $FB
.eq Z_FC		= $FC
.eq Z_FD		= $FD


.ba $E449
.wo	MainWaitLoopGS			;				[F72E]


.ba $E4B7
.fb $00,28				; unused


.ba $F199
GetByteTape:				;				[F199]
	jsr	DevNotPresntGS		;				[FB4D]


.ba $F19E
	jsr	DevNotPresntGS		;				[FB4D]


.ba $F1E5
	jsr	DevNotPresntGS		;				[FB4D]


.ba $F1EA
	jsr	DevNotPresntGS		;				[FB4D]


.ba $F2CE
	jsr	DevNotPresntGS		;				[FB4D]


.ba $F2D7
	jsr	DevNotPresntGS		;				[FB4D]


.ba $F2E8
	jsr	DevNotPresntGS		;				[FB4D]


.ba $F38B
A_F38B:					;				[F38B]
	jsr	DevNotPresntGS		;				[FB4D]


.ba $F399
	jsr	DevNotPresntGS		;				[FB4D]


.ba $F3A5
	jsr	DevNotPresntGS		;				[FB4D]


.ba $F3AF
A_F3AF:					;				[F3AF]
	jsr	DevNotPresntGS		;				[FB4D]


.ba $F3B8
A_F3B8:					;				[F3B8]
	jsr	DevNotPresntGS		;				[FB4D]


.ba $F3BF
	jsr	DevNotPresntGS		;				[FB4D]


.ba $F539
A_F539:					;				[F539]
	jsr	DevNotPresntGS		;				[FB4D]


.ba $F541
A_F541:					;				[F541]
	jsr	DevNotPresntGS		;				[FB4D]


.ba $F54D
	jsr	DevNotPresntGS		;				[FB4D]


.ba $F556
A_F556:					;				[F556]
	jsr	DevNotPresntGS		;				[FB4D]


.ba $F5A5
	jsr	DevNotPresntGS		;				[FB4D]


.ba $F65F
A_F65F:					;				[F65F]
	jsr	DevNotPresntGS		;				[FB4D]


.ba $F664
	jsr	DevNotPresntGS		;				[FB4D]


.ba $F677
	jsr	DevNotPresntGS		;				[FB4D]


.ba $F67C
	jsr	DevNotPresntGS		;				[FB4D]


.ba $F689
	jsr	DevNotPresntGS		;				[FB4D]


.ba $F72C
FindTapeHdr2:				;				[F72C]
	sec
	.by $24				; dummy BIT opcode
MainWaitLoopGS:				;				[F72E]
	clc
	ror	Z_FB
	php

	sei

	lda	#$0B			; bit 4 = 0: turn screen off
	sta	VICCTR1

	lda	#$17			; bits 1..3: character set at $D800
	sta	VICRAM			; bits 4..7: video RAM at $0400

;**  Clear screen and colour it black
	ldx	#$00
A_F73F:					;				[F73F]
	lda	#$00
	sta	ColourRAM,X
	sta	ColourRAM+$100,X
	sta	ColourRAM+$200,X
	sta	ColourRAM+$300,X

	lda	#' '			; space
	sta	VICSCN,X
	sta	VICSCN+$100,X
	sta	VICSCN+$200,X
	sta	VICSCN+$300,X

	inx				; whole page done?
	bne	A_F73F			; no, -> 


;**  Fill part of video screen with shifted space or graphic pattern
	lda	#<(VICSCN+$53)
	sta	Z_FC

	lda	#>(VICSCN+$53)
	sta	Z_FD

	ldx	#$15
A_F768:					;				[F768]
	ldy	#33			; 33 lines
	lda	#$A0			; shifted space
A_F76C:					;				[F76C]
	sta	(Z_FC),Y

	dey
	bne	A_F76C


	clc
	lda	Z_FC
	adc	#40			; next line
	sta	Z_FC

	bcc	A_F77C

	inc	Z_FD
A_F77C:					;				[F77C]
	dex				; all lines?
	bne	A_F768			; no, -> 


	lda	#' ' 
	sta	VICSCN+$74
	sta	VICSCN+$374


;**  Fill colour RAM
	lda	#$0E
	ldx	#$1F
A_F78B:					;				[F78B]
	sta	ColourRAM+$54,X
	sta	ColourRAM+$7C,X
	sta	ColourRAM+$A4,X
	sta	ColourRAM+$324,X
	sta	ColourRAM+$34C,X

	dex
	bpl	A_F78B


	ldx	#<(ColourRAM+$CC)
	stx	Z_FC

	ldx	#>(ColourRAM+$CC)
	stx	Z_FD

	ldx	#$0F
A_F7A7:					;				[F7A7]
	lda	#$0E
	ldy	#$00
	sta	(Z_FC),Y

	ldy	#$1F
	sta	(Z_FC),Y

	clc
	lda	Z_FC
	adc	#40			; next line
	sta	Z_FC

	bcc	A_F7BC

	inc	Z_FD
A_F7BC:					;				[F7BC]
	dex
	bne	A_F7A7

	bit	Z_FB
	bpl	A_F7CA

	lda	#$1B			; bit 4 = 1: turn screen on
	sta	VICCTR1

	plp
	rts


;**  Fill screen memory with data (1)
A_F7CA:					;				[F7CA]
	ldx	#$00
A_F7CC:					;				[F7CC]
	lda	D_F8CA,X
	beq	A_F7D9

	sta	VICSCN+$81,X

	inx
	bpl	A_F7CC


;**  Fill screen memory with data (2)
	ldx	#$07
A_F7D9:					;				[F7D9]
	lda	D_F8E5,X
	sta	VICSCN+$3F8,X

	dex
	bpl	A_F7D9


;**  Copy sprites into locations
	ldx	#$3F
A_F7E4:					;				[F7E4]
	lda	D_F90D,X
	sta	VICSCN+$0A00,X

	lda	D_F94D,X
	sta	VICSCN+$0A40,X

	lda	D_F98D,X
	sta	VICSCN+$0A80,X

	lda	D_F9CD,X
	sta	VICSCN+$0AC0,X

	lda	D_FA0D,X
	sta	VICSCN+$0B00,X

	lda	D_FA4D,X
	sta	VICSCN+$0B40,X

	lda	D_FA8D,X
	sta	VICSCN+$0B80,X

	dex
	bpl	A_F7E4


	lda	#$04
	sta	VICSPMC

	lda	#$73
	sta	VICESPH

;* Another sprite
J_F81B:					;				[F81B]
	ldx	#$3F
A_F81D:					;				[F81D]
	lda	D_FACD,X
	sta	VICSCN+$0BC0,X

	dex
	bpl	A_F81D


	ldx	#$0F
A_F828:					;				[F828]
	lda	D_F8ED,X
	sta	VICSBCO,X

	lda	D_F8FD,X
	sta	VIC_chip,X

	dex
	bpl	A_F828


	lda	#$1B
	sta	VICCTR1

	lda	#$BE
	sta	VICSPEN

	jsr	P_F89F			;				[F89F]

	lda	#$FC
	sta	VICSPEN

	jsr	P_F8AB			;				[F8AB]

	lda	#$BD
	sta	VICSPEN

	jsr	P_F8A8			;				[F8A8]

	lda	#$3D
	sta	VICSPEN

	jsr	P_F8A8			;				[F8A8]
A_F85C:					;				[F85C]
	inc	VICSP3Y
	jsr	P_F8AE			;				[F8AE]

	ldx	VICSP3Y
	cpx	#$7C
	bcc	A_F85C

	jsr	P_F8A8			;				[F8A8]

	ldx	#$3F
A_F86E:					;				[F86E]
	lda	D_FB0D,X
	sta	VICSCN+$0BC0,X

	dex
	bpl	A_F86E

	lda	#$05
	sta	VICCSP7

	lda	#$7C
	sta	VICSPEN

	jsr	P_F8AB			;				[F8AB]

	lda	#$3E
	sta	VICSPEN

	jsr	P_F8A8			;				[F8A8]

	lda	#$BE
	sta	VICSPEN

	jsr	P_F89F			;				[F89F]

	lda	#$04
	sta	VICSPEN

	jsr	P_F8A8			;				[F8A8]

	jmp	J_F81B			;				[F81B]


P_F89F:					;				[F89F]
	jsr	P_F8A8			;				[F8A8]
	jsr	P_F8A8			;				[F8A8]
	jsr	P_F8A8			;				[F8A8]
P_F8A8:					;				[F8A8]
	ldy	#$28
	.by $2C				; dummy BIT opcode
P_F8AB:					;				[F8AB]
	ldy	#$06
	.by $2C				; dummy BIT opcode
P_F8AE:					;				[F8AE]
	ldy	#$02
A_F8B0:					;				[F8B0]
	jsr	P_F8BF			;				[F8BF]

	dey
	bne	A_F8B0

	jsr	Chk4Cartridge		; cartridge found?		[FD02]
	beq	A_F8BC			; yes, -> reset

	rts

A_F8BC:					;				[F8BC]
	jmp	($FFFC)


P_F8BF:					;				[F8BF]
	bit	VICCTR1
	bmi	P_F8BF
A_F8C4:					;				[F8C4]
	bit	VICCTR1
	bpl	A_F8C4

	rts

 
D_F8CA:					;				[F8CA]
.by $C3, $8F, $8D, $8D, $8F, $84, $8F, $92
.by $85, $A0, $C3, $B6, $B4, $A0, $C7, $81
.by $8D, $85, $93, $A0, $D3, $99, $93, $94
.by $85, $8D, $00

D_F8E5:					;				[F8E5]
.by $38, $39, $3A, $3B, $3C, $3D, $3E, $3F

D_F8ED:					;				[F8ED]
.by $00, $06, $06, $01, $02, $03, $06, $01
.by $0F, $0F, $0A, $0F, $0F, $0F, $0F, $02

D_F8FD:					;				[F8FD]
.by $E0, $7E, $E0, $7E, $43, $43, $94, $64
.by $90, $82, $60, $82, $E0, $7E, $AC, $A7

D_F90D:					;				[F90D]
.by $80, $00, $00, $80, $00, $00, $FF, $C0
.by $00, $C0, $40, $00, $C0, $40, $00, $C0
.by $40, $00, $C0, $C0, $00, $C1, $80, $00
.by $C3, $00, $00, $C6, $00, $60, $CC, $00
.by $90, $C8, $00, $90, $C8, $40, $90, $C8
.by $80, $90, $C9, $F8, $60, $C8, $80, $00
.by $C8, $46, $77, $D8, $09, $44, $F0, $09
.by $66, $80, $09, $44, $80, $06, $44, $00

D_F94D:					;				[F94D]
.by $80, $00, $40, $80, $00, $40, $F0, $00
.by $40, $D8, $40, $40, $C8, $80, $40, $C9
.by $F8, $40, $C8, $80, $00, $C8, $43, $24
.by $C8, $04, $B4, $C8, $04, $AC, $C8, $04
.by $A4, $CC, $03, $24, $C6, $00, $00, $C3
.by $00, $00, $C1, $80, $00, $C0, $80, $00
.by $C0, $80, $00, $C0, $80, $00, $FF, $80
.by $00, $80, $00, $00, $80, $00, $00, $00

D_F98D:					;				[F98D]
.by $00, $00, $00, $00, $00, $00, $00, $00
.by $00, $01, $54, $00, $05, $54, $00, $05
.by $54, $00, $15, $54, $00, $15, $02, $A8
.by $14, $02, $A0, $14, $02, $80, $14, $00
.by $00, $14, $03, $C0, $14, $03, $F0, $15
.by $03, $FC, $15, $54, $00, $05, $54, $00
.by $05, $54, $00, $01, $54, $00, $00, $00
.by $00, $00, $00, $00, $00, $00, $00, $00

D_F9CD:					;				[F9CD]
.by $1F, $FF, $E0, $30, $00, $A0, $3F, $FF
.by $A0, $3F, $FF, $A0, $20, $00, $A0, $20
.by $00, $A0, $20, $00, $A0, $3F, $FF, $A0
.by $3F, $FF, $A0, $3F, $FF, $A0, $3F, $FF
.by $A0, $3F, $FF, $C0, $3F, $FF, $80, $00
.by $00, $00, $00, $60, $00, $00, $60, $00
.by $00, $60, $00, $03, $6C, $00, $01, $F8
.by $00, $00, $F0, $00, $00, $60, $00, $00

D_FA0D:					;				[FA0D]
.by $00, $00, $00, $00, $00, $00, $BF, $FF
.by $7C, $BF, $FF, $7D, $7F, $FE, $F9, $60
.by $06, $FB, $DF, $ED, $F3, $80, $1D, $F6
.by $FF, $FB, $E6, $FF, $FB, $EC, $FF, $F7
.by $CC, $FF, $F7, $D8, $FF, $EF, $98, $FF
.by $EF, $B0, $FF, $DF, $30, $00, $00, $60
.by $FF, $FF, $60, $FF, $FF, $C0, $FF, $FF
.by $C0, $00, $00, $00, $00, $00, $00, $00

D_FA4D:					;				[FA4D]
.by $00, $00, $00, $00, $00, $00, $03, $FF
.by $FF, $03, $FF, $FF, $07, $FF, $FF, $07
.by $FF, $FF, $0F, $FF, $FE, $0F, $FF, $FE
.by $1F, $FF, $FD, $1F, $FF, $FD, $3F, $FF
.by $FB, $3F, $FF, $FB, $7F, $FF, $F7, $7F
.by $FF, $F7, $FF, $FF, $EF, $80, $00, $00
.by $FF, $FF, $FF, $FF, $FF, $FF, $FF, $FF
.by $FF, $00, $00, $00, $00, $00, $00, $00

D_FA8D:					;				[FA8D]
.by $80, $00, $00, $80, $00, $00, $FE, $00
.by $00, $C1, $00, $00, $C1, $00, $00, $C2
.by $00, $00, $C2, $00, $00, $C4, $00, $00
.by $C4, $00, $00, $C8, $00, $00, $C8, $00
.by $00, $C8, $00, $00, $C4, $00, $00, $C4
.by $00, $00, $C2, $00, $00, $C2, $00, $00
.by $C1, $00, $00, $C1, $00, $00, $FE, $00
.by $00, $80, $00, $00, $80, $00, $00, $00

D_FACD:					;				[FACD]
.by $00, $00, $00, $E0, $00, $38, $F0, $00
.by $78, $78, $00, $F0, $3C, $01, $E0, $1E
.by $03, $C0, $0F, $07, $80, $07, $8F, $00
.by $03, $DE, $00, $01, $FC, $00, $00, $F8
.by $00, $00, $F8, $00, $01, $FC, $00, $03
.by $DE, $00, $07, $8F, $00, $0F, $07, $80
.by $1E, $03, $C0, $3C, $01, $E0, $78, $00
.by $F0, $F0, $00, $78, $E0, $00, $38, $00

D_FB0D:					;				[FB0D]
.by $00, $00, $00, $00, $00, $38, $00, $00
.by $78, $00, $00, $F0, $00, $01, $E0, $00
.by $03, $C0, $00, $07, $80, $00, $0F, $00
.by $00, $1E, $00, $00, $3C, $00, $60, $78
.by $00, $E0, $F0, $00, $E1, $E0, $00, $E3
.by $C0, $00, $E7, $80, $00, $EF, $00, $00
.by $FE, $00, $00, $FC, $00, $00, $F8, $00
.by $00, $F0, $00, $00, $E0, $00, $00, $00
 
DevNotPresntGS:				;				[FB4D]
	jmp	DevNotPresent		;				[F707]

; not used 
S_FB50:
.fb $00,62


.ba $FB97
SetCounter:				;				[FB97]
.fb $00,$69

.by "COPYRIGHT 1990 COMMODORE ELECTRONICS LTD. ALL RIGHTS RESERVED."

.fb $00,$16


.ba $FC57
J_FC57:					;				[FC57]
.fb $00,$3C


.ba $FD83
	nop
	bne	A_FD6C


.ba $FD9B
TapeIrqVectors:				;				[FD9B]
.wo	End_RS232_NMI			;				[FEBC]
.wo	End_RS232_NMI			;				[FEBC]
.wo	End_RS232_NMI			;				[FEBC]
.wo	End_RS232_NMI			;				[FEBC]


;******************************************************************************