Marsport: Routine at A606

A606: Key press update

Used by the routine at _87c9.
Sets the action flags based on which keys are pressed.
Keys_UpdateAction	A606	LD A,(Flag_Demo)
	A609	AND A
	A60A	JP NZ,Keys_UpdateAction_9
	A60D	CALL Keyboard_GetState
	A610	LD B,$00	Holds the bits represent which type of action is required.
	A612	LD IX,KeyState_ShiftToV	Holds the bits represent which type of action is required.
	A616	LD A,(IX+$01)	Mask off keys A,D & G
	A619	AND $15
	A61B	LD C,A
	A61C	LD A,(IX+$06)	Mask off keys J & L
	A61F	AND $0A	Mask off keys J & L
	A621	OR C	OR into single result.
	A622	XOR $1F	Flip bits and see if anything was pressed.
	A624	JR Z,Keys_UpdateAction_0	Flip bits and see if anything was pressed.
	A626	SET 2,B	If so, then set the bit for rotate clockwise.
Keys_UpdateAction_0	A628	LD A,(IX+$01)	Check for keys S & F
	A62B	AND $0A
	A62D	LD C,A
	A62E	LD A,(IX+$06)	Check for keys H, K & ENTER
	A631	SET 0,A
	A633	AND $15
	A635	OR C
	A636	XOR $1F	Flip bits and see if anything was pressed.
	A638	JR Z,Keys_UpdateAction_1	Flip bits and see if anything was pressed.
	A63A	SET 3,B	If so, set the bit for rotate anti-clockwise.
Keys_UpdateAction_1	A63C	LD A,(IX+$00)	Check for keys Z & C
	A63F	AND $0A
	A641	LD C,A
	A642	LD A,(IX+$07)	Check for keys B & M
	A645	AND $14
	A647	OR C
	A648	XOR $1E	Flip bits and see if anything was pressed.
	A64A	JR Z,Keys_UpdateAction_2	Flip bits and see if anything was pressed.
	A64C	SET 1,B	If so, then set the bit for walk left.
Keys_UpdateAction_2	A64E	LD A,(IX+$00)	Check for keys X & V
	A651	AND $14
	A653	LD C,A
	A654	LD A,(IX+$07)	Check for keys N & Symbol Shift
	A657	AND $0A
	A659	OR C
	A65A	XOR $1E	Flip bits and check if anything was pressed.
	A65C	JR Z,Keys_UpdateAction_3	Flip bits and check if anything was pressed.
	A65E	SET 0,B	If so, then set bit for walking right.
Keys_UpdateAction_3	A660	LD A,(IX+$02)	Check for keys W & R
	A663	AND $0A
	A665	LD C,A
	A666	LD A,(IX+$05)	Check for keys Y, I & P
	A669	AND $15
	A66B	OR C
	A66C	XOR $1F	Flip bits and see if anything was pressed.
	A66E	JR Z,Keys_UpdateAction_4	Flip bits and see if anything was pressed.
	A670	SET 6,B	If so, then set bit for drop.
Keys_UpdateAction_4	A672	LD A,(IX+$02)	Check for keys Q, E & T
	A675	AND $15
	A677	LD C,A
	A678	LD A,(IX+$05)	Check for keys U & O
	A67B	AND $0A
	A67D	OR C
	A67E	XOR $1F	Flip bits and see if anything was pressed.
	A680	JR Z,Keys_UpdateAction_5	Flip bits and see if anything was pressed.
	A682	SET 5,B	If so, then set bit for pick up.
Keys_UpdateAction_5	A684	LD A,(IX+$03)	Check for keys 1 to 5
	A687	XOR (IX+$04)	include keys 6 to 0
	A68A	AND $1E
	A68C	JR Z,Keys_UpdateAction_6
	A68E	SET 7,B	Check bit for special / menu action.
Keys_UpdateAction_6	A690	LD A,(IX+$00)
	A693	AND (IX+$07)
	A696	AND (IX+$03)
	A699	AND (IX+$04)
	A69C	AND $01
	A69E	JR NZ,Keys_UpdateAction_7
	A6A0	SET 4,B
Keys_UpdateAction_7	A6A2	LD A,B
	A6A3	LD (KeyState_Actions),A
	A6A6	LD A,($BD1F)
	A6A9	ADD A,B
	A6AA	LD ($BD1F),A
	A6AD	LD A,(IX+$06)
	A6B0	AND $01
	A6B2	XOR $01
	A6B4	JR Z,Keys_UpdateAction_8
	A6B6	LD A,$FF
Keys_UpdateAction_8	A6B8	LD ($BD2B),A
	A6BB	RET
Keys_UpdateAction_9	A6BC	LD (KeyState_Actions),A
	A6BF	XOR A
	A6C0	LD ($BD2B),A
	A6C3	RET