kolibrios/kernel/trunk/core/hpet.inc

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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; ;;
;; Copyright (C) KolibriOS team 2004-2022. All rights reserved. ;;
;; Distributed under terms of the GNU General Public License ;;
;; ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
$Revision$
HPET_ID = 0x0000
HPET_PERIOD = 0x0004
HPET_CFG_ENABLE = 0x0001
HPET_CFG = 0x0010
HPET_COUNTER = 0x00f0
HPET_T0_CFG = 0x0100
HPET_TN_LEVEL = 0x0002
HPET_TN_ENABLE = 0x0004
HPET_TN_FSB = 0x4000
uglobal
hpet_base rd 1
hpet_period rd 1
hpet_timers rd 1
hpet_tsc_start rd 2
endg
align 4
init_hpet:
mov ebx, [hpet_base]
test ebx, ebx
jz .done
mov eax, [ebx]
and ah, 0x1F
inc ah
movzx eax, ah
mov [hpet_timers], eax
mov ecx, eax
mov eax, [ebx + HPET_PERIOD]
xor edx, edx
shld edx, eax, 10
shl eax, 10
mov esi, 1000000
div esi
mov [hpet_period], eax
mov esi, [ebx + HPET_CFG]
and esi, not HPET_CFG_ENABLE
mov [ebx + HPET_CFG], esi ;stop main counter
lea edx, [ebx + HPET_T0_CFG]
@@:
jcxz @F
mov eax, [edx]
and eax, not (HPET_TN_ENABLE + HPET_TN_LEVEL + HPET_TN_FSB)
mov [edx], eax
add edx, 0x20
dec ecx
jmp @B
@@:
mov [ebx + HPET_COUNTER], ecx ;reset main counter
mov [ebx + HPET_COUNTER + 4], ecx
or esi, HPET_CFG_ENABLE
mov [ebx + HPET_CFG], esi ;and start again
.done:
rdtsc
mov [hpet_tsc_start], eax
mov [hpet_tsc_start + 4], edx
ret