Routines
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D7E7: Choose Sea Creature
Used by the routine at Handler_SeaCreatures.
Input
IX Sea creature slot
Fetch a random-ish number.
Handler_SeaCreatures_Chooser D7E7 CALL UpdateAnimationCounter Call UpdateAnimationCounter.
D7EA AND %00000111 Ensure the number is between 00 to 04.
D7EC SUB $02
D7EE CP $05
D7F0 JR C,Handler_SetSeaCreature
D7F2 LD A,$04
Handler_SetSeaCreature D7F4 LD E,A Create an offset in DE using A.
D7F5 LD D,$00
This is simply HL=TableDefaultSeaCreatures+(A*18).
D7F7 SLA E DE*=08.
D7F9 SLA E
D7FB SLA E
D7FD PUSH DE HL=DE (using the stack).
D7FE POP HL
D7FF SLA E HL+=DE*02.
D801 RL D
D803 ADD HL,DE
D804 LD DE,$D93E HL+=TableDefaultSeaCreatures.
D807 ADD HL,DE
D808 PUSH IX DE=IX (using the stack).
D80A POP DE
D80B LD BC,$0018 BC=0018.
D80E LDIR Copy 0018 bytes of data from the chosen creature defaults table to the creature slot.
Fetch a random-ish number.
Handler_SetSeaCreatureYPosition D810 CALL UpdateAnimationCounter Call UpdateAnimationCounter.
D813 AND %00001111 Keep only bits 0-3.
D815 ADD A,$06 A+=06.
D817 CP $11 Jump to Handler_SetSeaCreatureYPosition if A is higher than 11.
D819 JR NC,Handler_SetSeaCreatureYPosition
D81B RES 0,A Reset bit 0 of A.
D81D LD (IX+$01),A Write A to *IX+01.
D820 LD (IX+$0E),A Write A to *IX+0E.
D823 PUSH IY Stash IY on the stack.
D825 LD IY,$DB46 IY=Data_SeaCreatures.
D829 LD L,A L=A.
D82A LD BC,($DD98) BC=*DD98.
Handler_SeaCreatures_Chooser_0 D82E LD A,(IY+$0A) Jump to Handler_SeaCreatures_Chooser_1 if *IY+0A is equal to 00.
D831 CP $00
D833 JR Z,Handler_SeaCreatures_Chooser_1
D835 LD A,(IY+$01) Jump to Handler_SeaCreatures_Chooser_1 if *IY+01 is not equal to L.
D838 CP L
D839 JR NZ,Handler_SeaCreatures_Chooser_1
D83B LD A,(IY+$00) Jump to Handler_SeaCreatures_Chooser_2 if *IY+00 is higher than 0F.
D83E CP $0F
D840 JP NC,Handler_SeaCreatures_Chooser_2
Handler_SeaCreatures_Chooser_1 D843 LD DE,$0018 IY+=0018.
D846 ADD IY,DE
D848 DJNZ Handler_SeaCreatures_Chooser_0 Decrease counter by one and loop back to Handler_SeaCreatures_Chooser_0 until counter is zero.
D84A POP IY Restore IY from the stack.
D84C LD A,$01 Write 01 to *IX+0A.
D84E LD (IX+$0A),A
D851 LD A,$22 A=22+*IX+07.
D853 ADD A,(IX+$07)
D856 LD (IX+$00),A Write A to *IX+00.
D859 LD (IX+$0D),A Write A to *IX+0D.
D85C LD (IX+$02),$01 Write 01 to *IX+02.
D860 LD (IX+$0B),$01 Write 01 to *IX+0B.
D864 JP Handler_SeaCreatures_Next Jump to Handler_SeaCreatures_Next.
Handler_SeaCreatures_Chooser_2 D867 POP IY Restore IY from the stack.
D869 JP Handler_SeaCreatures_Next Jump to Handler_SeaCreatures_Next.
D86C POP IX Restore IX from the stack.
D86E RET Return.
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