Chase H.Q.: Routine at 9023

9023: Routine at 9023

Used by the routine at main_loop_23.

Input
A	?
BC	? Sampled: $0D20, $0520, $0120
HL	? Sampled: $EEAC, $EEA4, $EEA0
IX	? Sampled: $EACE, $EAEE, $EAFE

9023

LD E,A

E = A -- sampled = 5 (only)

9024

CP $02

Jump if A == 2

9026

JR Z,$902E

A != 2

9028

LD A,(IX+$01)

A = IX[1]

902B

AND A

Set flags

902C

JR NZ,main_loop_23_2

Loop?

902E

PUSH IX

Preserve IX, HL, BC

9030

PUSH HL

9031

PUSH BC

9032

LD A,E

DE = E * 7

9033

ADD A,A

9034

ADD A,A

9035

ADD A,A

9036

SUB E

9037

LD E,A

9038

LD D,$00

903A

LD HL,$904B

Set return address

903D

PUSH HL

903E

LD HL,($5CFE)

turn sign lods

9041

ADD HL,DE

HL += DE

sampled HL = $5EA4 (only) which is "Entry 14"

9042

LD E,(HL)

DE = wordat(HL); HL += 2 -- arg for routine

9043

INC HL

9044

LD D,(HL)

9045

INC HL

9046

LD A,(HL)

HL = wordat(HL) -- address of routine

9047

INC HL

9048

LD H,(HL)

9049

LD L,A

B is used in the routines, what is it here? It must be passed in.

904A

JP (HL)

Indirect jump -- Call draw_stretchy_object_left draw_stretchy_object_right draw_tunnel_light_left draw_tunnel_light_right draw_object_right etc.

return_904B

904B

POP BC

Restore IX, HL, BC

904C

POP HL

904D

POP IX

904F

JP main_loop_23_2

Loop?