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system_routines:interrupt_scheduler [2016/06/05 16:34] ex_writer [STIMER] |
system_routines:interrupt_scheduler [2016/06/11 22:23] (current) ex_writer [CTIMER] |
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| Line 24: | Line 24: | ||
| 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 35: | 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 ==== | ||
