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51 lines
1.7 KiB
51 lines
1.7 KiB
3 years ago
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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struc SegmentDescriptor
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.wLimitLow RESW 1 ;�ν���16λ
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.wBaseLow RESW 1 ;����ַ��16λ
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.bBaseMiddle RESB 1 ;����ַ�м�8λ
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.bAttrib RESB 1 ;������
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.bLimitHight4Bit_AttribHight4Bit RESB 1 ;�ν��ĸ�4λ�Ͷ����Եĸ�4λ
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.bBaseHigh RESB 1 ;����ַ�ĸ�8λ
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endstruc
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; varaible ,offset,Base
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%macro SetDescriptor_Base_Offset 3
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xor eax, eax
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mov ax, %3
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shl eax, 4
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add eax, %2
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mov word [%1 + SegmentDescriptor.wBaseLow], ax
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shr eax, 16
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mov byte [%1 + SegmentDescriptor.bBaseMiddle], al
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mov byte [%1 + SegmentDescriptor.bBaseHigh], ah
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%endmacro
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; varaible , Base
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%macro SetDescriptor_Base 2
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mov eax,%2
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mov word [%1 + SegmentDescriptor.wBaseLow], ax
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shr eax, 16
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mov byte [%1 + SegmentDescriptor.bBaseMiddle], al
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mov byte [%1 + SegmentDescriptor.bBaseHigh], ah
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%endmacro
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; %1 new descriptor name
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; %2 base : 32 bit
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; %3 limit : 20 bit
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; %4 attribute ; 12 bit
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%macro NewDescriptor 4
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%1:
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istruc SegmentDescriptor
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at SegmentDescriptor.wLimitLow , dw %3 & 0xffff
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at SegmentDescriptor.wBaseLow , dw %2 & 0xffff
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at SegmentDescriptor.bBaseMiddle, db (%2>>16) & 0xff
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at SegmentDescriptor.bAttrib , db %4 & 0xff
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at SegmentDescriptor.bLimitHight4Bit_AttribHight4Bit, db ( (%3>>16) & 0x0F) | (%4 >> 8)
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at SegmentDescriptor.bBaseHigh , db (%2 >> 24) & 0xff
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iend
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%endmacro
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