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Updated scheduler - now change_task and irq0 handler don't intersect so ugly. The code became more straightforward. By the way, it is also faster.

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git-svn-id: svn://kolibrios.org@101 a494cfbc-eb01-0410-851d-a64ba20cac60
This commit is contained in:
Ivan Poddubny 2006-07-20 17:55:40 +00:00
parent d925b54ad5
commit ad532cdbaa
1 changed files with 90 additions and 69 deletions
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159
kernel/trunk/core/sched.inc
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@ -2,6 +2,7 @@
;; IRQ0 HANDLER (TIMER INTERRUPT) ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
align 32
irq0:
save_ring3_context
@ -9,11 +10,6 @@ irq0:
mov ds, ax
mov es, ax
mov edi,[0x3000]
shl edi, 3
; fields of TSS descriptor:
; mov [edi+gdts+ tss0 +5], word 01010000b *256 +11101001b
inc dword [timer_ticks]
mov eax, [timer_ticks]
@ -26,21 +22,90 @@ irq0:
call updatecputimes
.nocounter:
mov edi, [0x3010]
cmp [0xffff], byte 1
jne .change_task
mov al,0x20 ; send End Of Interrupt signal
mov dx,0x20
out dx,al
mov [0xffff], byte 0
restore_ring3_context
iret
.change_task:
call update_counters
call find_next_task
mov ecx, eax
mov al,0x20 ; send End Of Interrupt signal
mov dx,0x20
out dx,al
test ecx, ecx ; if there is only one running process
jnz .return
call do_change_task
.return:
restore_ring3_context
iret
align 4
change_task:
pushfd
cli
pushad
call update_counters
call find_next_task
test eax, eax ; the same task -> skip switch
jnz .return
mov [0xffff],byte 1
call do_change_task
.return:
popad
popfd
ret
uglobal
align 4
far_jump:
.offs dd ?
.sel dw ?
context_counter dd ? ;noname & halyavin
next_usage_update dd ?
timer_ticks dd ?
prev_slot dd ?
event_sched dd ?
endg
update_counters:
mov edi, [0x3010]
mov ebx, [edi+0x18] ; time stamp counter add
call _rdtsc
sub eax, ebx
add eax, [edi+0x14] ; counter sum
mov [edi+0x14], eax
ret
; Find next task to execute
; result: ebx = number of the selected task
; [0xffff] = 1 if the task is the same
find_next_task:
mov ebx,[0x3000]
mov [prev_slot], ebx
cmp [0xffff], byte 1
je .do_not_change_task
.waiting_for_termination:
.waiting_for_reuse:
.waiting_for_event:
@ -55,6 +120,8 @@ irq0:
inc ebx
mov al, byte [edi+0xA]
test al, al
jz .found
cmp al, 1
jz .suspended
cmp al, 2
@ -77,73 +144,27 @@ irq0:
mov [event_sched], eax
mov [edi+0xA], byte 0
.noevents:
cmp ebx, [prev_slot]
sete [0xffff]
.do_not_change_task:
.found:
mov [0x3000],ebx
mov [0x3010],edi
call _rdtsc
mov [edi+0x18],eax
xor eax, eax
cmp ebx, [prev_slot]
sete al
ret
; in: ebx = TSS selector index
do_change_task:
shl ebx, 3
xor eax, eax
add ebx, tss0
mov word [far_jump.sel], bx ; selector
mov dword [far_jump.offs], eax ; offset
cmp [irq0needeoi],byte 0
mov [irq0needeoi],byte 1
jz .noeoi
mov al,0x20 ; send End Of Interrupt signal
mov dx,0x20
out dx,al
.noeoi:
cmp [0xffff],byte 0
je .switch
dec byte [0xffff]
jz @f
.switch:
mov [far_jump.sel], bx ; selector
mov [far_jump.offs], eax ; offset
jmp pword [far_jump]
inc [context_counter] ;noname & halyavin
@@:
restore_ring3_context
iret
uglobal
align 4
far_jump:
.offs dd ?
.sel dw ?
context_counter dd ? ;noname & halyavin
next_usage_update dd ?
timer_ticks dd ?
prev_slot dd ?
event_sched dd ?
endg
iglobal
irq0needeoi db 1
endg
align 4
change_task:
pushfd
cli
mov [0xffff],byte 2
mov [irq0needeoi],byte 0
dec dword [timer_ticks] ; because irq0 will increase it
int 0x20 ; irq0 handler
popfd
ret
ret