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system_routines:interrupt_scheduler [2016/06/05 16:31] ex_writer [ACTINT] |
system_routines:interrupt_scheduler [2016/06/11 22:23] (current) ex_writer [CTIMER] |
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| Line 21: | Line 21: | ||
| | Arguments: | None | | | Arguments: | None | | ||
| | Description: | ACTINT provides automatic [[hardware:interrupts|interrupt]] service and runs the seconds timer, the game timer, the music processor, and blackout timers, plus CT0–CT3. Functions as 60<sup>th</sup> of a second timers. | | | Description: | ACTINT provides automatic [[hardware:interrupts|interrupt]] service and runs the seconds timer, the game timer, the music processor, and blackout timers, plus CT0–CT3. Functions as 60<sup>th</sup> of a second timers. | | ||
| - | |Notes: | Once ACTINT is called, it sets: | + | |
| + | Once ACTINT is called, it sets: | ||
| * Z80 Interrupt mode 2 (IM 2) | * Z80 Interrupt mode 2 (IM 2) | ||
| - | * INLIN = 200 (line 100) | + | * INLIN = C8H = 200 (i.e., line 100) |
| * I register and Interrupt Feedback (INFBK) | * I register and Interrupt Feedback (INFBK) | ||
| * Enable interrupts (EI) | * Enable interrupts (EI) | ||
| - | ACTINT also calls TIMEX and TIMEY which decrement counters/timers. | | + | |
| + | ACTINT also calls TIMEX and TIMEY which decrement counters/timers. | ||
| + | |||
| + | <wrap alert>Appears to call TIMEZ rather than TIMEX? CTIMER calls TIMEX.</wrap> | ||
| ==== CTIMER ==== | ==== CTIMER ==== | ||
| Line 33: | Line 37: | ||
| | Calling Sequence: | <code z80>CALL CTIMER</code>| | | Calling Sequence: | <code z80>CALL CTIMER</code>| | ||
| | Input: | HL = address of custom time base\\ B = value to load into time base 1 to 0 transition\\ C = counter mask as in [[interrupt scheduler#deccts|DECCTS]] | | | Input: | HL = address of custom time base\\ B = value to load into time base 1 to 0 transition\\ C = counter mask as in [[interrupt scheduler#deccts|DECCTS]] | | ||
| - | | Description: | HL is loaded and decremented. If HL != 0, then a return is executed, otherwise, HL is loaded with B and [[interrupt scheduler#deccts|DECCTS]] is called.\\ \\ Registers HL, DE, BC, and AF are undefined upon exit. | | + | | Description: | Calls TIMEX, which decrements a time base in RAM (HL). If HL != 0, then a return is executed, otherwise, HL is loaded with B and [[interrupt scheduler#deccts|DECCTS]] is called.\\ \\ Registers HL, DE, BC, and AF are undefined upon exit. | |
| ==== BMUSIC ==== | ==== BMUSIC ==== | ||
| Line 62: | Line 66: | ||
| | Calling Sequence: | <code z80>SYSTEM EMUSIC</code> or <code z80>SYSSUK EMUSIC</code>| | | Calling Sequence: | <code z80>SYSTEM EMUSIC</code> or <code z80>SYSSUK EMUSIC</code>| | ||
| | Arguments: | None | | | Arguments: | None | | ||
| - | | Notes: | None | | ||
| | Description: | Outputs 0 to volume ports and halt music processor. | | | Description: | Outputs 0 to volume ports and halt music processor. | | ||
| - | | Restrictions: | None | | ||
| ==== STIMER ==== | ==== STIMER ==== | ||
| Line 74: | Line 76: | ||
| PUSH DE | PUSH DE | ||
| PUSH HL | PUSH HL | ||
| - | PUSH IX | ||
| - | PUSH IY | ||
| CALL STIMER | CALL STIMER | ||
| - | POP IY | ||
| - | POP IX | ||
| POP HL | POP HL | ||
| POP DE | POP DE | ||
| Line 85: | Line 83: | ||
| | Input: | None | | | Input: | None | | ||
| | Description: | STIMER keeps track of game time. If it hits 0, then bit 7 (GSBEND, i.e., game end) in the game status byte (GAMSTB) is set. | | | Description: | STIMER keeps track of game time. If it hits 0, then bit 7 (GSBEND, i.e., game end) in the game status byte (GAMSTB) is set. | | ||
| - | | Uses: | AF, BC, DE, HL | | + | | Notes: | Uses AF, BC, DE, and HL.\\ \\ Sets bit 7 of KEYSEX (KEYS-EX tracking byte) to 1 on every second. \\ \\ Calls music processor on note (duration) expiration. | |
| - | | Calls: | Music processor on note (duration) expiration | | + | |
| - | | Note: | Sets bit 7 of KEYSEX (KEYS-EX tracking byte) to 1 on every second | | + | |
