Grapple beam code.

Main grapple code in bank 9B
Current 0D32 values:
C4F0 (Inactive)
C856 (Hit nothing / cancel)
C8C5 (Released from swing or wallgrab)
C51E (Fire / goto cancel)
C703 (Firing)
C77E
C79D (Connected)
C9CE (Walljumping)
C814 (Wallgrab)
C832 (Wallgrab, not holding jump)


Code is jsred to at 90/DD5C according to which item is selected. 90/DD69 contains pointer to grapple code.
Currently, the grapple code just JSLs to 9BC490.


	PHP
	PHB
	PHK
	PLB
	REP #$30
	LDA $0CF6
	BEQ BRANCH_ALPHA
	DEC A
	STA $0CF6
BRANCH_ALPHA
	LDA $0A64
	AND #$FFFE
	STA $0A64
	JSR $B861  ;  $DB861 IN ROM
	PEA #$C4B0
	JMP ($0D32)
$DC4B1 ALTERNATE ENTRY POINT
	LDA $0D32
	CMP #$C4F0
	BEQ BRANCH_BETA
	CMP #$C856
	BPL BRANCH_BETA
	LDA $0A74	;Some sort of pallete index for Samus
	BIT #$0004
	BNE BRANCH_BETA
	LDA $196E
	BEQ BRANCH_BETA
	JSL $90EC58  ;Get Samus's boundaries
	LDA $195E	;Liquid height
	BMI BRANCH_BETA
	CMP $12
	BPL BRANCH_BETA
	LDA $0CF4
	ORA #$0001	;Set Samus below liquid
	STA $0CF4
	PLB
	PLP
	RTL
BRANCH_BETA
	LDA $0CF4
	AND #$FFFE	;Set Samus above liquid
	STA $0CF4
	PLB
	PLP
	RTL


;9B:B861
;If Samus can't fire grapple beam, set 0D32 to C856

	LDA $0A1F
	AND #$00FF
	TAX
	LDA $B8B8, X
;Check movement types that allow grapple beam (01 = not allowed)
;00 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f 10 11 12 13 14 15 16 17 18 19 1a 1b
;00 00 00 01 01 00 00 01 01 01 01 00 00 01 01 01 00 01 01 01 01 00 00 01 01 01 00 01
	AND #$00FF
	BEQ BRANCH_ALPHA
BRANCH_GAMMA
	LDA $0D32
	CMP #$C4F0
	BEQ BRANCH_BETA
	LDA #$C856
	STA $0D32
BRANCH_BETA
	RTS
BRANCH_ALPHA
	LDA $0D32
	CMP #$C4F0
	BEQ BRANCH_BETA
	CMP #$C77E
	BPL BRANCH_BETA
	LDA $0A1C
	ASL A
	ASL A
	ASL A
	TAX
	LDA $91B62C, X
	AND #$00FF
	BIT #$00F0	;Check pose firing direction
	BNE BRANCH_GAMMA
	CMP $0D34
	BNE BRANCH_DELTA
	RTS
BRANCH_DELTA
	LDA $0CF6
	BEQ BRANCH_GAMMA
	LDA #$0007
	JSL $809049  ;  $1049 IN ROM
	LDA #$C51E
	STA $0D32
	RTS

;C4F0: Do nothing if fire is/was not pressed. Clear charge beam if necessary. Setup grapple beam if fire is pressed.
	LDA $8F
	BIT $09B2
	BNE BRANCH_ALPHA
	LDA $0E00
	BIT $09B2
	BNE BRANCH_ALPHA
	LDA $0CD0
	BEQ BRANCH_BETA
	STZ $0CD0
	STZ $0CD6
	STZ $0CD8
	STZ $0CDA
	STZ $0CDC
	STZ $0CDE
	STZ $0CE0
	JSL $91DEBA  ;  $8DEBA IN ROM
BRANCH_BETA
	RTS
;C51E: Act as if fire was just pressed. This is often used to *cancel* the beam during no-fire conditions
BRANCH_ALPHA
	LDA $0A1C
	CMP #$00F0
	BEQ BRANCH_GAMMA
	CMP #$00BE
	BEQ BRANCH_GAMMA
	ASL A
	ASL A
	ASL A
	TAX
	LDA $91B62D, X
	AND #$00FF
	STA $16
	LDA $91B62C, X
	AND #$00FF
	BIT #$00F0
	BEQ BRANCH_DELTA
BRANCH_EPSILON
	LDA #$C856
	STA $0D32
	RTS
BRANCH_GAMMA
	JSR $C6B2  ;  Gets directions for Samus's aiming while held by Draygon
	{
		CMP #$00BE
		BEQ BRANCH_LAMBDA
		LDA #$0006
		STA $16
		LDA $8B
		BIT #$0100
		BEQ BRANCH_MU
		BIT #$0400
		BNE BRANCH_NU
		BIT #$0800
		BNE BRANCH_XI
	BRANCH_MU
		LDA #$0002
		SEC
		RTS
	BRANCH_XI
		LDA #$0001
		SEC
		RTS
	BRANCH_NU
		LDA #$0003
		SEC
		RTS
	BRANCH_LAMBDA
		LDA #$0006
		STA $16
		LDA $8B
		BIT #$0200
		BEQ BRANCH_OMICRON
		BIT #$0400
		BNE BRANCH_PI
		BIT #$0800
		BNE BRANCH_RHO
	BRANCH_OMICRON
		LDA #$0007
		SEC
		RTS
	BRANCH_RHO
		LDA #$0008
		SEC
		RTS
	BRANCH_PI
		LDA #$0006
		SEC
		RTS
        ;Two unused bytes after this: CLC, RTS
	}
	BCC BRANCH_EPSILON ;never branches, Samus can always fire when held by Draygon
BRANCH_DELTA
	STA $0D34
	ASL A
	TAX
	LDA $C0DB, X ;X speed
	STA $0D22
	LDA $C0EF, X ;Y speed
	STA $0D24
	LDA $C104, X ;Angle?
	STA $0CFA
	STA $0CFC
	LDA #$000A
	STA $0CF6
	LDA $0A1C
	CMP #$0049
	BEQ BRANCH_ZETA
	CMP #$004A
	BEQ BRANCH_ZETA
	LDA $0A1F
	AND #$00FF
	CMP #$0001
	BEQ BRANCH_THETA
BRANCH_ZETA ;Samus is not walking/running
	LDA $C122, X ;Initial grapple point X offset from Samus
	STA $0D02
	LDA $C136, X ;Initial grapple point Y offset from Samus
	SEC
	SBC $16
	STA $0D04
	LDA $0AF6
	PHA
	CLC
	ADC $C122, X
	STA $0D08    ;X position of grapple point
	STA $0D16    ;X position of grapple end
	PLA
	CLC
	ADC $C14A, X
	STA $0D1A    ;X position of grapple start
	LDA $0AFA
	SEC
	SBC $16
	PHA
	CLC
	ADC $C136, X
	STA $0D0C    ;Y position of grapple point
	STA $0D18    ;Y position of grapple end
	PLA
	CLC
	ADC $C15E, X
	STA $0D1C    ;Y position of grapple start
	BRA BRANCH_IOTA
BRANCH_THETA ;Samus is walking/running
	LDA $C172, X
	STA $0D02
	LDA $C186, X
	SEC
	SBC $16
	STA $0D04
	LDA $0AF6
	PHA
	CLC
	ADC $C172, X
	STA $0D08
	STA $0D16
	PLA
	CLC
	ADC $C19A, X
	STA $0D1A
	LDA $0AFA
	SEC
	SBC $16
	PHA
	CLC
	ADC $C186, X
	STA $0D0C
	STA $0D18
	PLA
	CLC
	ADC $C1AE, X
	STA $0D1C
BRANCH_IOTA ;Don't know most of the stuff here yet
	STZ $0D06
	STZ $0D0A
	STZ $0D0E
	STZ $0D10
	STZ $0D12
	STZ $0D14
	STZ $0CF4
	LDA #$000C
	STA $0D00
	STZ $0CFE
	STZ $0D26
	STZ $0D28
	STZ $0D2A
	STZ $0D2C
	STZ $0D2E
	STZ $0D30
	STZ $0D1E
	STZ $0D20
	LDA #$0002
	STA $0D3A
	STZ $0D3C
	LDA #$0005
	STA $0D3E
	LDA $C342
	STA $0D40
	STZ $0D82
	STZ $0D84
	STZ $0D86
	STZ $0D88
	STZ $0D8A
	STZ $0D8C
	STZ $0D8E
	STZ $0D90
	STZ $0D38
	STZ $0D36
	STZ $0CF8
	JSL $94AF87  ;  $A2F87 IN ROM
	{
		LDX #$001E
	BRANCH_ALPHA
		LDA #$B197
		STA $0D62, X ;0D80, 0D78, 0D70, 0D68
		LDA #$B193
		STA $0D60, X ;0D7E, 0D76, 0D6E, 0D66
		LDA #$B18F
		STA $0D5E, X ;0D7C, 0D74, 0D6C, 0D64
		LDA #$B18B
		STA $0D5C, X ;0D7A, 0D72, 0D6A, 0D62
		LDA #$0001
		STA $0D42, X ;0D60, 0D58, 0D50, 0D48
		STA $0D40, X ;0D5E, 0D56, 0D4E, 0D46
		STA $0D3E, X ;0D5C, 0D54, 0D4C, 0D44
		STA $0D3C, X ;0D5A, 0D52, 0D4A, 0D42
		TXA
		SEC
		SBC #$0008
		TAX
		BPL BRANCH_ALPHA
		RTL
	}
	LDA #$EB86
	STA $0A5C
	STZ $0A9E
	LDA #$0002
	JSL $90ACF0  ;  Just REP #$30 and JSR $ACFC, basically. ACFC shown here
	{
		AND #$0FFF
		ASL A
		TAY
		LDA #$0090
		XBA
		STA $01
		LDA $C3C9, Y
		STA $00
		LDY #$0000
		LDX #$0000
	BRANCH_ALPHA
		LDA [$00], Y
		STA $7EC1C0, X ;Setting colors... for what?
		INX
		INX
		INY
		INY
		CPY #$0020
		BMI BRANCH_ALPHA
		RTS
	}
	LDA #$7F91
	STA $7EC1BE  ; Setting some color
	LDA #$C703
	STA $0D32
	LDA #$0005   ; Start of grapple beam sound
	JSL $80903F  ;  $103F IN ROM
	LDA #$0001
	STA $0CD0    ; Current charge... why is this set?
	STZ $0DC0
	LDA $0A58
	CMP #$946E   ; Something with grapple
	BNE BRANCH_KAPPA
	LDA #$A337   ; Normal
	STA $0A58
BRANCH_KAPPA
	RTS


;C703:
	LDA $8B
	BIT $09B2
	BNE BRANCH_SIGMA
BRANCH_UPSILON
	LDA #$C856
	STA $0D32
	RTS
BRANCH_SIGMA
	JSR $B8D4  ;  RTS. >_>
	LDA $0CFE
	CLC
	ADC $0D00
	STA $0CFE
	CMP #$0080
	BMI BRANCH_TAU
BRANCH_CHI
	BRA BRANCH_UPSILON
BRANCH_TAU
	JSL $A09E9A  ; Grapple beam collision detection?
	{
		PHB
		PHX
		PHY
		LDA #$000D
		JSL $90F084  ;  A = 1 if GrappleFire != C4F0
		BNE BRANCH_ALPHA
		JMP BRANCH_IOTA
	BRANCH_ALPHA
		STZ $18A6
		STZ $17AA
	Jump_One
		LDY $17AA
		LDA $17EC, Y
		STA $0E54
		CMP #$FFFF
	BNE BRANCH_BETA
		STZ $12
		LDA #$0000
		PLY
		PLX
		PLB
		RTL
	BRANCH_BETA
		TAX
		LDA $0FA0, X
		BNE BRANCH_GAMMA
		LDA $0F7A, X
		SEC
		SBC $0D08
		BPL BRANCH_DELTA
		EOR #$FFFF
		INC A
	BRANCH_DELTA
		SEC
		SBC $0F82, X
		BCC BRANCH_EPSILON
		CMP #$0008
		BCS BRANCH_GAMMA
	BRANCH_EPSILON
		LDA $0F7E, X
		SEC
		SBC $0D0C
		BPL BRANCH_ZETA
		EOR #$FFFF
		INC A
	BRANCH_ZETA
		SEC
		SBC $0F84, X
		BCC BRANCH_THETA
		CMP #$0008
		BCC BRANCH_THETA
	BRANCH_GAMMA
		INC $17AA
		INC $17AA
		JMP Jump_One
	BRANCH_THETA
		LDA #$0001
		STA $0F8A, X
		LDY #$0000
		LDA $0F78, X
		TAX
		LDA $A0001A, X
		CMP #$8000
		BEQ BRANCH_IOTA
		LDY #$0001
		CMP #$8005
		BEQ BRANCH_IOTA
		INY
		CMP #$800A
		BEQ BRANCH_IOTA
		INY
		CMP #$800F
		BEQ BRANCH_IOTA
		INY
		CMP #$8014
		BEQ BRANCH_IOTA
		INY
		CMP #$8019
		BEQ BRANCH_IOTA
		INY
		CMP #$801E
		BEQ BRANCH_IOTA
		LDY #$0000
	BRANCH_IOTA
		STX $12
		TYA
		CMP #$0001
		BEQ BRANCH_KAPPA
		CMP #$0004
		BEQ BRANCH_KAPPA
		CMP #$0005
		BEQ BRANCH_KAPPA
	BRANCH_LAMBDA
		PLY
		PLX
		PLB
		RTL
	BRANCH_KAPPA ;Attach grapple point to enemy
		PHA
		LDX $0E54
		LDA $0F7A, X
		STA $0D08
		LDA $0F7E, X
		STA $0D0C
		PLA
		BRA BRANCH_LAMBDA
	}
	JSR $B907  ;  $DB907 IN ROM
	{
		ASL A
		TAX
		JMP ($B90C, X)  ;  $DB90C IN ROM
		DW $B91A, $B91C, $B921, $B923, $B928, $B92D, $B932
	;$DB91A
		CLC
		RTS
		
	;$DB91C ALTERNATE ENTRY POINT
		LDA #$0000
		SEC
		RTS
	
	;$DB921 ALTERNATE ENTRY POINT
		CLC
		RTS
	
	;$DB923 ALTERNATE ENTRY POINT
		LDA #$0001
		SEC
		RTS
	
	;$DB928 ALTERNATE ENTRY POINT
		LDA #$0000
		SEC
		RTS
	
	;$DB92D ALTERNATE ENTRY POINT
		LDA #$0000
		SEC
		RTS
	
	;$DB932 ALTERNATE ENTRY POINT
		LDX $12
		LDA $A00006, X	;Enemy contact damage
		STA $12
		LDA $09A2
		BIT #$0020
		BNE BRANCH_ALPHA
		LSR A
		BCC BRANCH_BETA
		LSR $12
	BRANCH_BETA
		LDA $12
		BRA BRANCH_GAMMA
	BRANCH_ALPHA
		LSR $12
		LSR $12
		LDA $12
	BRANCH_GAMMA
		JSL $91DF51  ;Deal damage (A) to Samus. Does NOT do any damage if damage = 300 (#$12C) or if time is paused by x-ray / reserve tanks, ignores suits. NOTE: If damage is negative, game will stop (JML $808573)
		LDA #$0060	;Set invincibility timer
		STA $18A8
		LDA #$0005	;Set hurt-timer
		STA $18AA
		LDA $0A1E
		AND #$00FF
		CMP #$0004	;Direction Samus is facing
		BEQ BRANCH_DELTA
		STZ $0A54	;Direction Samus moves while hurt
		BRA BRANCH_EPSILON
	BRANCH_DELTA
		LDA #$0001
		STA $0A54
	BRANCH_EPSILON
		LDA #$0001
		SEC
		RTS
	}
	BCC BRANCH_PHI
	TAY
	BNE BRANCH_CHI
	BRA BRANCH_PSI
BRANCH_PHI
	JSL $94A85B  ;  Grapple beam block collision checking and reaction.
	BCC BRANCH_OMEGA
	BVC BRANCH_CHI
BRANCH_PSI
	LDA #$0006
	JSL $809049  ;  Play grapple-attached sound
	JSR $B97C  ;  $DB97C IN ROM
	{
		LDA $0A1F
		AND #$00FF
		CMP #$001A
		BNE BRANCH_ALPHA
		LDA #$C77E
		STA $0D32	;Set for 'grabbed by draygon'
		STZ $0D00
		RTS
	BRANCH_ALPHA
		LDA $0D34
		ASL A
		ASL A
		TAX
		LDA $0B2E
		BNE BRANCH_BETA
		LDA $0B2C
		BNE BRANCH_BETA
		LDA $0A1F
		AND #$00FF
		CMP #$0005
		BEQ BRANCH_GAMMA
		LDA $C3C6, X	;C79D, C79D, C77E, C77E, C77E, C77E, C77E, C77E, C79D, C79D
		STA $0D32
		LDA $C3C8, X	;B9D9, B9D9, B9EA, B9F3, B9FC, B9FC, B9FC, BA05, B9E2, B9E2
		STA $0D82
		JMP ($0D82)
	BRANCH_GAMMA	;Samus is crouching
		LDA $C416, X	;C79D, C79D, C77E, C77E, C77E, C77E, C77E, C77E, C79D, C79D
		STA $0D32
		LDA $C418, X	;B9D9, B9D9, BA0E, BA17, B9FC, B9FC, BA20, BA29, B9E2, B9E2
		STA $0D82
		JMP ($0D82)
	BRANCH_BETA	;Samus is moving vertically
		LDA $C3EE, X	;C79D all
		STA $0D32
		LDA $C3F0, X	;B9D9 left, B9E2 right
		STA $0D82
		JMP ($0D82)
;B9D9: 0A2A = #00B2, goto BA61
;B9E2: 0A2A = #00B3, goto BA61
;B9EA: 0A2A = #00A8, goto BA9B
;B9F3: 0A2A = #00AA, goto BA9B
;B9FC: 0A2A = #00AB, goto BA9B
;BA05: 0A2A = #00A9, goto BA9B
;BA0E: 0A2A = #00B4, goto BA9B
;BA17: 0A2A = #00B6, goto BA9B
;BA20: 0A2A = #00B7, goto BA9B
;BA29: 0A2A = #00B5, goto BA9B
;BA61:
		LDA #$0009
		STA $0A30
		LDA $0AF6
		SEC
		SBC $0D08
		STA $12
		LDA $0AFA
		SEC
		SBC $0D0C
		STA $14
		JSL $A0C0AE  ;Calculate angle from Grapple point to Samus
		XBA
		STA $0CFA
		STA $0CFC
		STZ $0D00	;Keep grapple from shutting off
		LDA $0CFE
		CMP #$0040
		BMI BRANCH_ALPHA
		SEC
		SBC #$0018
		STA $0CFE
	BRANCH_ALPHA
		JSL $94AC11  ;  $A2C11 IN ROM
		{
			LDA $0CFB
			AND #$00FF
			ASL A
			STA $0D82
			LDA $0CFE
			STA $0D84
			JSR $A957  ;  $A2957 IN ROM
			LDA $0D90
			STA $0D16
			LDA $0D92
			STA $0D18
			RTL
		}
		RTS
;BA9B: 0A30 = #000A, rest is identical to BA61
	}
	LDA #$0008
	EOR #$FFFF
	INC A
	STA $0D00
	LDA $0A64
	ORA #$0001
	STA $0A64
BRANCH_OMEGA
	RTS