Routines
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40381: Index ID Table
Used by the routines at Start, Drawing, DisplayLocHlpMsg, Action_Dir, Action_Examine, 39557, 39809, LocateObject and ActionClimbOut.
Input
A Key ID
IX Address of table data
Output
IX The address in the table which matches the key ID
Searches through what is essentially key value data to find a key match.
IndexIdTable 40381 EXX Exchange registers.
40382 PUSH IX HL=IX (using the stack to do so).
40384 POP HL
40385 LD B,A B=key ID
40386 LD E,3 DE=$0003 as each record is 3 bytes of data.
40388 LD D,0
Begin searching the table.
IndexIdTable_Loop 40390 LD A,(HL) Grab the next ID.
40391 CP B If the key ID is the one we want, jump to IndexIdTable_Found.
40392 JR Z,IndexIdTable_Found
40394 CP 255 If we've reached the termination character (key ID not found), jump to IndexIdTable_Found.
40396 JR Z,IndexIdTable_Found
40398 ADD HL,DE Add DE to HL to check the next row, and jump back to IndexIdTable_Loop to continue checking.
40399 JP IndexIdTable_Loop
Handle the output.
IndexIdTable_Found 40402 PUSH HL IX=HL (using the stack to do so).
40403 POP IX
40405 CP 255 Set flags (checking if the key ID was not found).
40407 EXX Exchange registers.
40408 RET Return.
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