71188c92f9
- support of TSS-based task switching - add a mailbox template - suport of user level task - support of system calls git-svn-id: http://svn.lfbs.rwth-aachen.de/svn/scc/trunk/MetalSVM@47 315a16e6-25f9-4109-90ae-ca3045a26c18
147 lines
2.9 KiB
NASM
147 lines
2.9 KiB
NASM
;
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; Copyright 2010 Stefan Lankes, Chair for Operating Systems,
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; RWTH Aachen University
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;
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; Licensed under the Apache License, Version 2.0 (the "License");
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; you may not use this file except in compliance with the License.
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; You may obtain a copy of the License at
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;
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; http://www.apache.org/licenses/LICENSE-2.0
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;
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; Unless required by applicable law or agreed to in writing, software
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; distributed under the License is distributed on an "AS IS" BASIS,
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; WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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; See the License for the specific language governing permissions and
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; limitations under the License.
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;
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; This file is part of metalsvm.
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[BITS 32]
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SECTION .code
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extern get_new_task
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extern current_task
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;extern task_table
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; C prototyp:
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;
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; typedef struct {
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; unsigned char* top;
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; unsigned int ip;
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; tid_t id;
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; ...
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; } task_t;
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; After an interrupt, the original return address has to push on the stack
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; because we want to comeback...
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global schedule_entry
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schedule_entry:
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cli
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sub esp, 4 ; add some space for the retunr address,
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; which is stored in current_task->ip
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pushfd
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pusha
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push ds
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push es
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push fs
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push gs
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mov ax, 0x10
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mov ds, ax
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mov es, ax
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mov fs, ax
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mov gs, ax
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;mov eax, DWORD [current_id]
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;shl eax, 0x4 ; 16 = sizeof(task_t)
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;mov edx, DWORD [eax+task_table+4]
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;mov [esp+13*4], edx
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;mov DWORD [eax+task_table+4], 0
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mov eax, DWORD [current_task]
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mov edx, [eax+4]
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mov DWORD [esp+13*4], edx
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mov DWORD [eax+4], 0x00
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jmp L1
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; Scheduler, which switchs to the new tasks
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global schedule
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schedule:
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ret
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cli
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; return address is already on the stack (via call schedule)
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pop eax
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pushfd
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push 0x08
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push eax
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push byte 0
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push byte 32
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pusha
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push ds
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push es
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push fs
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push gs
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mov ax, 0x10
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mov ds, ax
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mov es, ax
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mov fs, ax
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mov gs, ax
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mov eax, DWORD [current_task]
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mov [eax], esp
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;call get_new_task
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mov DWORD [current_task], eax
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mov esp, [eax]
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pop gs
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pop fs
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pop es
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pop ds
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popa
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add esp, 8
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xor eax, eax ; return value is 0
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iret
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cli
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pushfd
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pusha
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push ds
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push es
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push fs
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push gs
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mov ax, 0x10
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mov ds, ax
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mov es, ax
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mov fs, ax
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mov gs, ax
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; store current esp
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;mov eax, DWORD [current_id]
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;shl eax, 0x4 ; 16 = sizeof(task_t)
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L1:
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;mov [eax+task_table], esp
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mov eax, DWORD [current_task]
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mov [eax], esp
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;call get_new_task
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; set current task and restore esp
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;mov DWORD [current_id], eax
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;shl eax, 0x4 ; 16 = sizeof(task_t)
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;mov esp, [eax+task_table]
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mov DWORD [current_task], eax
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mov esp, [eax]
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pop gs
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pop fs
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pop es
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pop ds
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popa
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popfd
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sti
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ret
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