Routines
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60167: Process Final Phase Enemy Entity
Used by the routine at Process_Replacement_Enemy_Entity.
Per-frame handler for the final phase of a wall-bouncing enemy, reached from Process_Replacement_Enemy_Entity when the replacement entity countdown expires. Spawns the entity with colour WHITE, calls Find_Colliding_Entity to search for a player-contact slot, and jumps to Process_Final_Phase_Enemy_Entity_Kill if none is found. Calls HitTestBounds8AtHL to test player contact and jumps to Strip_Attributes_And_Fade to kill the player if touching. Steps back to the direction field and generates a random value; keeps the current direction if below 240 otherwise picks a new direction, wraps it within 51 and writes it back. Looks up Y and X deltas from Enemy_Movement_Delta_Table (direction & 3 × 2), validates the new position within the play area, and spawns the entity. If no contact slot is found, erases the sprite, removes the entity from the list, awards BCD score, and writes the retire handler.
Input
HL Entity record pointer
Advance past the countdown byte and spawn with white colour.
Process_Final_Phase_Enemy_Entity 60167 INC HL Advance past the countdown field.
60168 PUSH HL Stash the entity pointer on the stack.
60169 EXX Load WHITE into B'.
60170 LD B,7
60172 EXX
60173 CALL Draw_Wide_Entity_Sprite Call Draw_Wide_Entity_Sprite to spawn the entity.
60176 POP HL Restore the entity pointer from the stack.
60177 INC HL Advance one byte and switch to alternate registers.
60178 EXX
Search for a player-contact slot and test overlap.
60179 CALL Find_Colliding_Entity Call Find_Colliding_Entity to search for a player-contact slot and jump to Process_Final_Phase_Enemy_Entity_Kill if none is found.
60182 JP NC,Process_Final_Phase_Enemy_Entity_Kill
60185 LD HL,50388 Load the player position at Player_Y_Position and call HitTestBounds8AtHL to test overlap.
60188 CALL HitTestBounds8AtHL
60191 JP NC,Strip_Attributes_And_Fade Jump to Strip_Attributes_And_Fade to kill the player if contact is confirmed.
60194 EXX Switch to main registers.
Step back to the direction field and pick or keep a direction.
60195 DEC HL Step back three bytes to the direction field.
60196 DEC HL
60197 DEC HL
60198 CALL Generate_Random_Byte Call Generate_Random_Byte to generate a random value.
60201 CP 240 Keep the current direction if the value is below 240.
60203 JP C,Process_Final_Phase_Enemy_Entity_Keep
Increment and mask the direction byte.
Process_Final_Phase_Enemy_Entity_Retry 60206 DEC HL Step back to the direction field, load it, and increment it.
60207 LD A,(HL)
60208 INC A
60209 AND %00110011 Mask the direction within 51.
60211 LD (HL),A Write the new direction, advance, and jump to Process_Final_Phase_Enemy_Entity_Apply.
60212 INC HL
60213 JP Process_Final_Phase_Enemy_Entity_Apply
Process_Final_Phase_Enemy_Entity_Keep 60216 DEC HL Step back to the direction field, load it, and advance.
60217 LD A,(HL)
60218 INC HL
Look up movement deltas and validate the new position.
Process_Final_Phase_Enemy_Entity_Apply 60219 EX DE,HL Exchange DE and HL.
60220 AND %00000011 Mask the direction to the low 2 bits.
60222 SLA A Double the index, load the movement table base at Enemy_Movement_Delta_Table, and step to the entry.
60224 LD C,A
60225 LD B,0
60227 LD HL,60340
60230 ADD HL,BC
60231 EX DE,HL Add the Y delta to the entity Y position and jump to Process_Final_Phase_Enemy_Entity_Retry if outside 16–170.
60232 LD A,(DE)
60233 ADD A,(HL)
60234 CP 171
60236 JP NC,Process_Final_Phase_Enemy_Entity_Retry
60239 CP 16
60241 JP C,Process_Final_Phase_Enemy_Entity_Retry
60244 LD C,A Save the validated Y position in C.
60245 INC HL Advance to the X position, apply the X delta, and jump to Process_Final_Phase_Enemy_Entity_X_Retry if outside the play area.
60246 INC DE
60247 LD A,(DE)
60248 ADD A,(HL)
60249 CP 241
60251 JP NC,Process_Final_Phase_Enemy_Entity_X_Retry
60254 CP 8
60256 JP NC,Process_Final_Phase_Enemy_Entity_Write
Process_Final_Phase_Enemy_Entity_X_Retry 60259 DEC HL Step back one byte and jump to Process_Final_Phase_Enemy_Entity_Retry to retry.
60260 JP Process_Final_Phase_Enemy_Entity_Retry
Write the validated coordinates and spawn with a random colour.
Process_Final_Phase_Enemy_Entity_Write 60263 LD (HL),A Write the validated X and Y coordinates to the entity record.
60264 DEC HL
60265 LD (HL),C
60266 DEC HL
60267 PUSH HL Stash the entity pointer on the stack.
60268 EXX Switch to alternate registers.
60269 CALL Generate_Random_Byte Call Generate_Random_Byte to generate a random colour byte.
60272 AND %00111000 Mask to bits 3–5 to select the spawn colour.
60274 LD B,A Load the colour into B and switch to main registers.
60275 EXX
60276 CALL Draw_Wide_Entity_Sprite Call Draw_Wide_Entity_Sprite to spawn the entity.
60279 POP HL Restore the entity pointer from the stack.
60280 JP Process_Entity_Record_Next6 Jump to Process_Entity_Record_Next6 to advance the entity pointer.
Erase the entity, remove it from the list, and award the score.
Process_Final_Phase_Enemy_Entity_Kill 60283 LD DE,6 Step back six bytes to the entity record and save the address in Entity_Record_Pointer.
60286 SBC HL,DE
60288 LD (50394),HL
60291 CALL Erase_Narrow_Entity_Sprite Call Erase_Narrow_Entity_Sprite to erase the entity sprite.
60294 CALL Remove_Entity_From_List Call Remove_Entity_From_List to remove the entity from the list.
60297 LD E,0 Load code 0 and call Initialise_Entity_State to initialise the entity state.
60299 CALL Initialise_Entity_State
Increment the BCD score and propagate carry to higher digits.
60302 LD HL,50181 Load 50181, add 1 BCD, write it back, and jump to Process_Final_Phase_Enemy_Entity_Score_Bar if no carry.
60305 LD A,(HL)
60306 ADD A,1
60308 DAA
60309 LD (HL),A
60310 JR NC,Process_Final_Phase_Enemy_Entity_Score_Bar
60312 DEC HL Carry to the tens digit: load, add 1 BCD, write back, and jump to Process_Final_Phase_Enemy_Entity_Score_Bar if no carry.
60313 LD A,(HL)
60314 ADD A,1
60316 DAA
60317 LD (HL),A
60318 JR NC,Process_Final_Phase_Enemy_Entity_Score_Bar
60320 DEC HL Carry to the hundreds digit: load, add 1 BCD, and write back.
60321 LD A,(HL)
60322 ADD A,1
60324 DAA
60325 LD (HL),A
Refresh the colour bar and write the retire handler.
Process_Final_Phase_Enemy_Entity_Score_Bar 60326 CALL Clear_Colour_Bar_Column Call Clear_Colour_Bar_Column to refresh the colour bar.
60329 EXX Switch to main registers.
60330 DEC HL Step back three bytes to the entity handler field.
60331 DEC HL
60332 DEC HL
60333 LD DE,57388 Write the retire handler Process_Entity_Record_Next7 into the entity record.
60336 LD (HL),D
60337 DEC HL
60338 LD (HL),E
60339 RET Return.
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