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Routines |
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| 61483 | CALL 61440 | Close any doors that need closing, decrement and check the blown fuse delay counters, update the on-screen message if necessary, and increment the score and decrement Sam's cash supply at regular intervals | ||
| 61486 | CALL 61568 | Update the icon panel, draw the bullets, and scan the event table at 24544 | ||
| 61489 | CALL 61948 | Move the characters | ||
| 61492 | LD A,(32764) | Pick up Sam's status flags from 32764 | ||
| 61495 | AND A | Is Sam in the middle of an action? | ||
| 61496 | JR Z,61509 | Jump if not | ||
| 61498 | CALL 29912 | Otherwise deal with Sam | ||
| 61501 | JR NZ,61549 | Jump if Sam has not finished the action yet | ||
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This entry point is used by the routines at 24914 and 61630.
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| 61503 | LD HL,5 | Reset Sam's main action timer and midstride/mid-action timer (in bytes 8 and 9 of his buffer) to 5 and 0 now that he's finished the action | ||
| 61506 | LD (58888),HL | |||
| 61509 | LD HL,58889 | Collect Sam's midstride/mid-action timer from byte 9 of his buffer | ||
| 61512 | LD A,(HL) | |||
| 61513 | AND A | Is Sam midstride or in the middle of a short action at the moment? | ||
| 61514 | JR NZ,61545 | Jump if so | ||
| 61516 | DEC L | Point HL at Sam's main action timer in byte 8 of his buffer | ||
| 61517 | DEC (HL) | Decrement it | ||
| 61518 | JR NZ,61549 | Jump unless it's time to check the keyboard | ||
| 61520 | LD (HL),2 | Reset Sam's main action timer to 2 | ||
| 61522 | CALL 31126 | Check for keypresses | ||
| 61525 | JR Z,61549 | Jump if there haven't been any | ||
| 61527 | LD (32765),A | Store the offset of the last keypress in 32765 | ||
| 61530 | LD H,237 | Point HL at the appropriate entry in the table of keypress handling routines at 60672 | ||
| 61532 | LD L,A | |||
| 61533 | LD DE,61549 | Push the address 61549 (see below) onto the stack so we return there after dealing with the keypress | ||
| 61536 | PUSH DE | |||
| 61537 | LD B,(HL) | Copy the address of the routine for dealing with the keypress into BC | ||
| 61538 | DEC L | |||
| 61539 | LD C,(HL) | |||
| 61540 | PUSH BC | Push this address onto the stack | ||
| 61541 | LD HL,58880 | Point HL at byte 0 of Sam's buffer | ||
| 61544 | RET | Make an indirect jump to the relevant keypress-handling routine, and then return to 61549 | ||
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Sam is midstride or in the middle of a short action (which involves raising his arm or bending his knees) at the moment.
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| 61545 | DEC (HL) | Decrement Sam's midstride/mid-action timer in byte 9 of his buffer | ||
| 61546 | CALL Z,60539 | If it's now zero, move Sam from the midstride/mid-action position, update the SRB, and scroll the screen if necessary | ||
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Now that Sam's movements have been dealt with, the main loop continues.
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| 61549 | CALL 60032 | Update the display | ||
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This next section of code ensures that we don't pass through the main loop more than once every 1/50th of a second.
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| 61552 | LD HL,32712 | HL=32712 (which holds the LSB of the system variable FRAMES as it was when the last pass through the main loop was completed) | ||
| 61555 | LD A,(23672) | A=LSB of the system variable FRAMES, which is incremented every 1/50th of a second | ||
| 61558 | SUB (HL) | Now A=0 if FRAMES hasn't been incremented since the last pass through the main loop | ||
| 61559 | CP 1 | Was FRAMES incremented? | ||
| 61561 | JR C,61555 | Jump back if not to check again | ||
| 61563 | ADD A,(HL) | Store the current value of the LSB of FRAMES at 32712 | ||
| 61564 | LD (HL),A | |||
| 61565 | JR 61483 | Jump back to the start of the main loop | ||
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