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| author | H. Peter Anvin <hpa@zytor.com> | 2009-09-02 17:44:32 -0700 |
|---|---|---|
| committer | H. Peter Anvin <hpa@zytor.com> | 2009-09-02 17:44:32 -0700 |
| commit | 75d4dec2f651c9f25fa95d6b6960db7c4dcfd7a0 (patch) | |
| tree | 1fc477d5f43577a31eaaff7c5a17f719c4e69e1d /core/include | |
| parent | 94a6e382a7a253fdab67a3bff981844dd5f6d4cb (diff) | |
| download | syslinux-75d4dec2f651c9f25fa95d6b6960db7c4dcfd7a0.tar.gz | |
core: hook INT 1Ch for a simple monotonic timer
The BIOS_timer variable at 4C6h is somewhat unreliable... it is
documented to wrap at "midnight", norminally after 1627419 ticks
(0x18d51b), which is a rather awkward number to deal with modulo.
Instead, hook the INT 1Ch secondary timer interrupt and just count a
simple incrementing variable.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Diffstat (limited to 'core/include')
| -rw-r--r-- | core/include/core.h | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/core/include/core.h b/core/include/core.h index c13aa16f..dbcbff1c 100644 --- a/core/include/core.h +++ b/core/include/core.h @@ -43,5 +43,13 @@ void call16(void (*)(void), const com32sys_t *, com32sys_t *); __noreturn _kaboom(void); #define kaboom() _kaboom() +/* + * Basic timer function... + */ +extern const volatile uint32_t __jiffies; +static inline uint32_t jiffies(void) +{ + return __jiffies; +} #endif /* CORE_H */ |