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kernel: get_clock_ns() funny 96-bit arithmetic

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git-svn-id: svn://kolibrios.org@6942 a494cfbc-eb01-0410-851d-a64ba20cac60
This commit is contained in:
Sergey Semyonov (Serge) 2017-08-11 16:17:30 +00:00
parent d8ccef567e
commit 2cbf514c37
1 changed files with 11 additions and 4 deletions
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15
kernel/trunk/core/apic.inc
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@ -460,17 +460,24 @@ get_clock_ns:
jne @B
popfd
;96-bit arithmetic
;ebx - low dword
;esi - medium dword
;edx - high dword
mul [hpet_period]
mov ebx, eax
mov esi, edx
mov eax, ecx
mul [hpet_period]
add eax, esi
mov edx, eax
add esi, eax
adc edx, 0
mov eax, ebx
shrd eax, edx, 10
shr edx, 10
mov ebx, esi
shrd eax, ebx, 10
shrd esi, edx, 10
mov edx, esi
pop esi
pop ebx