6bed7e5140
called early for console i/o. The timer is usually in BIOS mode if it isn't explicitly initialized. Then it counts twice as fast and has a max count of 65535 instead of 11932. The larger count tended to cause infinite loops for delays of > 20 us. Such delays are rare. For syscons and kbdio, DELAY() is only called early enough to matter for ddb input after booting with -d, and the delay is too small to matter (and too small to be correct) except in the PC98 case. For pcvt, DELAY() is not used for small delays (pcvt uses its own broken routine instead of the standard broken one), but some versions call DELAY() with a large arg when they unnecessarily initialize the keyboard for doing console output. The problem is more serious for pcvt because there is always some early console output. Guard against the i8254 timer being partially or incorrectly initialized. This would have prevented the endless loop. Should be in 2.2. |
||
|---|---|---|
| .. | ||
| clock.c | ||
| icu.h | ||
| isa.c | ||
| isa.h | ||
| npx.c | ||
| timerreg.h | ||
| vector.s | ||
| vector.S | ||