Kieron Morris
64b3c9a7ba
Added the apache license to all source files, accounting for authors. Also added a license.md containing the apache license + contributors.md listing all contributors.
89 lines
2.3 KiB
ObjectPascal
89 lines
2.3 KiB
ObjectPascal
// Copyright 2021 Kieron Morris
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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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Interrupt Descriptor Table - Structures & Interface.
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@author(Kieron Morris <kjm@kieronmorris.me>)
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}
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unit idt;
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interface
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uses
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util, console;
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const
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ISR_RING_0 = $8E;
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ISR_RING_1 = $AE;
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ISR_RING_2 = $CE;
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ISR_RING_3 = $EE;
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type
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TIDT_Entry = packed record
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base_low : uint16;
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selector : uint16;
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always_0 : uint8;
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flags : uint8;
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base_high : uint16;
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end;
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PIDT_Entry = ^TIDT_Entry;
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TIDT_Pointer = packed record
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limit : uint16;
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base : uint32;
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end;
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PIDT_Pointer = ^TIDT_Pointer;
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var
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IDT_Entries : Array [0..255] of TIDT_Entry;
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IDT_Pointer : TIDT_Pointer;
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procedure init();
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procedure set_gate(Number : uint8; Base : uint32; Selector : uint16; Flags : uint8);
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implementation
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procedure load(idt_pointer : uint32); assembler; nostackframe;
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asm
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MOV EAX, idt_pointer
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LIDT [EAX]
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end;
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procedure set_gate(Number : uint8; Base : uint32; Selector : uint16; Flags : uint8);
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begin
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IDT_Entries[Number].base_high:= (Base and $FFFF0000) SHR 16;
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IDT_Entries[Number].base_low:= (Base and $0000FFFF);
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IDT_Entries[Number].selector:= Selector;
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IDT_Entries[Number].flags:= Flags;
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IDT_Entries[Number].always_0:= $00;
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console.output('IDT','GATE ');
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console.writeint(Number);
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console.writestringln(' SET.');
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load(uint32(@IDT_Pointer));
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end;
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procedure init();
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begin
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console.outputln('IDT','INIT START.');
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IDT_Pointer.limit:= (sizeof(TIDT_Entry) * 256) - 1;
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IDT_Pointer.base:= uint32(@IDT_Entries);
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console.outputln('IDT','CLEAR.');
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util.memset(uint32(@IDT_Entries[0]), 0, sizeof(TIDT_Entry) * 256);
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console.outputln('IDT','LOAD.');
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load(uint32(@IDT_Pointer));
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console.outputln('IDT','INIT END.');
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end;
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end. |