| 2,6 → 2,7 |
|---|
| ;; IRQ0 HANDLER (TIMER INTERRUPT) ;; |
| ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; |
| |
| |
| align 32 |
| irq0: |
| save_ring3_context |
| 9,11 → 10,6 |
|---|
| 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 |
|---|
| call updatecputimes |
| .nocounter: |
| |
| 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 |
|---|
| inc ebx |
| |
| mov al, byte [edi+0xA] |
| test al, al |
| jz .found |
| cmp al, 1 |
| jz .suspended |
| cmp al, 2 |
| 77,72 → 144,26 |
|---|
| 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 |
| |
| |