Routines
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54634: Script Routine: (55) Collectible action
Pick a random continuation from the collectible's script table.
Input
IX Address of complex state data for an entity
ScriptRoutine_CollectibleRandomScript 54634 LD A,4 ..
54636 CALL PseudoRandom Call PseudoRandom to pick a pseudo-random value and keep it in B.
54639 LD B,A
54640 INC B Advance the loop index in B.
54641 ADD A,A Double A to form a word index into the script/handler table.
54642 LD C,A Keep the index in C.
54643 LD A,128 Load A with 128.
Rotate a bit mask until it differs from this collectible's direction / state.
ScriptRoutine_CollectibleRandomScript_RotateMask 54645 RLC A Rotate the collectible bitmask in A left circular.
54647 DJNZ ScriptRoutine_CollectibleRandomScript_RotateMask Decrease the loop counter in B and jump to ScriptRoutine_CollectibleRandomScript_RotateMask if more iterations remain.
54649 CP (IX+9) Does A match this entity's direction/state (IX+9)? If so, jump to ScriptRoutine_CollectibleRandomScript.
54652 JR Z,ScriptRoutine_CollectibleRandomScript
54654 LD (IX+9),A Set the current entity's direction / state.
54657 AND %00000011 Keep only the low two direction bits of A.
54659 JR NZ,ScriptRoutine_CollectibleRandomScript_RandomMax1E Jump to ScriptRoutine_CollectibleRandomScript_RandomMax1E to continue if the comparison did not match.
54661 LD A,2 Load A with 2.
54663 JR ScriptRoutine_CollectibleRandomScript_SetCounterAndScript Jump to ScriptRoutine_CollectibleRandomScript_SetCounterAndScript to continue this routine.
Use random maximum 30 when the new mask is not in the low two direction bits.
ScriptRoutine_CollectibleRandomScript_RandomMax1E 54665 LD A,30 Load A with 30.
Reseed the collectible counter and launch the matching script word from Data_CollectibleScriptTable.
ScriptRoutine_CollectibleRandomScript_SetCounterAndScript 54667 CALL PseudoRandom Call PseudoRandom to pick a pseudo-random value.
54670 INC A Advance 30 by one.
54671 LD (29372),A Set the collectible counter (CollectibleCounter).
54674 LD HL,54626 Point HL at unused padding before the collectible script (Data_CollectibleScriptTable).
54677 ADD HL,BC Add the length/offset in BC to the pointer in HL.
54678 LD C,(HL) Fetch the new script address into BC.
54679 INC HL
54680 LD B,(HL)
54681 LD L,C Copy the script address from BC into HL.
54682 LD H,B
54683 JP ScriptInstruction Jump to ScriptInstruction to execute the script instruction at HL.
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