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prot2.asm
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Assembly Source File
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1989-03-19
|
21KB
|
437 lines
PAGE ,132
TITLE Protected mode programming #2
.286P
MakeDescriptor MACRO Limit,BaseHword,BaseLbyte,Access
Dw Limit
Dw BaseHword
Db BaseLbyte
Db Access
Dw 0
ENDM
Descriptor STRUC
Lim Dw ? ; Limit
BaseW Dw ? ; Base address high
BaseB Db ? ; Base address low (byte)
Acc Db ? ; Access bytes right
Dw 0 ; Reserved
Descriptor ENDS
; Access rights typical equates
CODE_SEGMENT EQU 10011011b ; Code Segmnet Access Byte
DATA_SEGMENT EQU 10010011b ; Data Segment Access byte
TRAP_GATE EQU 10000111b ; Trap gate
INT_GATE EQU 10000110b ; Interrupt gate access
Null_Selector EQU 0h ;
Gdt_Alias_Selector EQU 8h ;
Idt_Alias_Selector EQU 10h ;
Ds_Selector EQU 18h ;
Es_Selector EQU 20h ;
Ss_Selector EQU 28h ;
Main_Code_Selector EQU 30h ;
BiosCs_Selector EQU 38h ;
Int_Code_Selector EQU 40h ;
GDT Segment
;=============================================================================;
; The GDT. ;
;=============================================================================;
Gdt_Start LABEL BYTE
MakeDescriptor 0,0,0,0 ; Null descriptor
MakeDescriptor Gdt_End,0,0,DATA_SEGMENT ; Gdt Alias
MakeDescriptor Idt_End,0,0,DATA_SEGMENT ; IDT Alias
MakeDescriptor 0,0,0,DATA_SEGMENT ; Ds Descriptor
MakeDescriptor 4000h,8000h,0Bh,DATA_SEGMENT; Es (Color Screen)
MakeDescriptor 0,0,0,DATA_SEGMENT ; Stack
MakeDescriptor 0,0,0,CODE_SEGMENT ; Code to execute
MakeDescriptor 0,0,0,CODE_SEGMENT ; Bios Temp
MakeDescriptor 0,0,0,CODE_SEGMENT ; Ex/Int code seg
Gdt_End LABEL BYTE
GDT Ends
IDT Segment
;=============================================================================;
; The IDT. ;
;=============================================================================;
Idt_Start LABEL BYTE
MakeDescriptor I00,Int_Code_Selector,0,TRAP_GATE ; divide by 0
MakeDescriptor I01,Int_Code_Selector,0,TRAP_GATE ; Single Step
MakeDescriptor I02,Int_Code_Selector,0,INT_GATE ; NMI
MakeDescriptor I03,Int_Code_Selector,0,TRAP_GATE ; Breakpoint trap
MakeDescriptor I04,Int_Code_Selector,0,TRAP_GATE ; INTO trap
MakeDescriptor I05,Int_Code_Selector,0,TRAP_GATE ; BOUNDS trap
MakeDescriptor I06,Int_Code_Selector,0,TRAP_GATE ; Invalid Opcode
MakeDescriptor I07,Int_Code_Selector,0,TRAP_GATE ; Math Cp Not Avail
MakeDescriptor I08,Int_Code_Selector,0,TRAP_GATE ; Double Fault
MakeDescriptor I09,Int_Code_Selector,0,TRAP_GATE ; Cp operand past lim
MakeDescriptor I0A,Int_Code_Selector,0,TRAP_GATE ; Invalid TSS
MakeDescriptor I0B,Int_Code_Selector,0,TRAP_GATE ; Cs,Ds,Es Not Present
MakeDescriptor I0C,Int_Code_Selector,0,TRAP_GATE ; Ss not present
MakeDescriptor I0D,Int_Code_Selector,0,TRAP_GATE ; Gen Prot Violation
MakeDescriptor 0,0,0,0 ; Reserved
MakeDescriptor 0,0,0,0 ; Reserved
MakeDescriptor I10,Int_Code_Selector,0,TRAP_GATE ; Calculation error x287
Db (32-17)*8 Dup(0) ; 17-31 reserved/unused
MakeDescriptor I20,Int_Code_Selector,0,INT_GATE ; Int 20h
MakeDescriptor I21,Int_Code_Selector,0,INT_GATE ; Int 21h
MakeDescriptor I22,Int_Code_Selector,0,INT_GATE ; Int 22h
MakeDescriptor I23,Int_Code_Selector,0,INT_GATE ; Int 23h
MakeDescriptor I24,Int_Code_Selector,0,INT_GATE ; Int 24h
MakeDescriptor I24,Int_Code_Selector,0,INT_GATE ; Int 25h
MakeDescriptor I26,Int_Code_Selector,0,INT_GATE ; Int 26h
MakeDescriptor I27,Int_Code_Selector,0,INT_GATE ; Int 27h
Db (64-40)*8 Dup(0) ;
Idt_End LABEL BYTE
IDT Ends
Int_Seg Segment
;=============================================================================;
; This is where all the interruptts go to!! ;
;=============================================================================;
Assume Cs:Int_Seg
I00:
Mov Ax,Es_Selector ;
Mov Es,Ax ; Make the screen acessable
Mov Al,'0' ; Int number calling
Mov Ah,7 ;
Mov Di,0 ;
Cld ;
Stosw ;
Iret ; Back!!
I01:
Mov Ax,Es_Selector ;
Mov Es,Ax ; Make the screen acessable
Mov Al,'1' ; Int number calling
Mov Ah,7 ;
Mov Di,0 ;
Cld ;
Stosw ;
Iret ; Back!!
I02:
Mov Ax,Es_Selector ;
Mov Es,Ax ; Make the screen acessable
Mov Al,'2' ; Int number calling
Mov Ah,7 ;
Mov Di,0 ;
Cld ;
Stosw ;
Iret ; Back!!
I03:
Mov Ax,Es_Selector ;
Mov Es,Ax ; Make the screen acessable
Mov Al,'3' ; Int number calling
Mov Ah,7 ;
Mov Di,0 ;
Cld ;
Stosw ;
Iret ; Back!!
I04:
Mov Ax,Es_Selector ;
Mov Es,Ax ; Make the screen acessable
Mov Al,'4' ; Int number calling
Mov Ah,7 ;
Mov Di,0 ;
Cld ;
Stosw ;
Iret ; Back!!
I05:
Mov Ax,Es_Selector ;
Mov Es,Ax ; Make the screen acessable
Mov Al,'5' ; Int number calling
Mov Ah,7 ;
Mov Di,0 ;
Cld ;
Stosw ;
Iret ; Back!!
I06:
Mov Ax,Es_Selector ;
Mov Es,Ax ; Make the screen acessable
Mov Al,'6' ; Int number calling
Mov Ah,7 ;
Mov Di,0 ;
Cld ;
Stosw ;
Iret ; Back!!
I07:
Mov Ax,Es_Selector ;
Mov Es,Ax ; Make the screen acessable
Mov Al,'7' ; Int number calling
Mov Ah,7 ;
Mov Di,0 ;
Cld ;
Stosw ;
Iret ; Back!!
I08:
Mov Ax,Es_Selector ;
Mov Es,Ax ; Make the screen acessable
Mov Al,'8' ; Int number calling
Mov Ah,7 ;
Mov Di,0 ;
Cld ;
Stosw ;
Iret ; Back!!
I09:
Mov Ax,Es_Selector ;
Mov Es,Ax ; Make the screen acessable
Mov Al,'9' ; Int number calling
Mov Ah,7 ;
Mov Di,0 ;
Cld ;
Stosw ;
Iret ; Back!!
I0A:
Mov Ax,Es_Selector ;
Mov Es,Ax ; Make the screen acessable
Mov Al,'A' ; Int number calling
Mov Ah,7 ;
Mov Di,0 ;
Cld ;
Stosw ;
Iret ; Back!!
I0B:
Mov Ax,Es_Selector ;
Mov Es,Ax ; Make the screen acessable
Mov Al,'B' ; Int number calling
Mov Ah,7 ;
Mov Di,0 ;
Cld ;
Stosw ;
Iret ; Back!!
I0C:
Mov Ax,Es_Selector ;
Mov Es,Ax ; Make the screen acessable
Mov Al,'C' ; Int number calling
Mov Ah,7 ;
Mov Di,0 ;
Cld ;
Stosw ;
Iret ; Back!!
I0D:
Mov Ax,Es_Selector ;
Mov Es,Ax ; Make the screen acessable
Mov Al,'D' ; Int number calling
Mov Ah,7 ;
Mov Di,0 ;
Cld ;
Stosw ;
Iret ; Back!!
I10:
Mov Ax,Es_Selector ;
Mov Es,Ax ; Make the screen acessable
Mov Al,'Q' ; Int number calling
Mov Ah,7 ;
Mov Di,0 ;
Cld ;
Stosw ;
Iret ; Back!!
I20:
Mov Ax,Es_Selector ;
Mov Es,Ax ; Make the screen acessable
Mov Al,'R' ; Int number calling
Mov Ah,7 ;
Mov Di,0 ;
Cld ;
Stosw ;
Iret ; Back!!
I21:
Mov Ax,Es_Selector ;
Mov Es,Ax ; Make the screen acessable
Mov Al,'S' ; Int number calling
Mov Ah,7 ;
Mov Di,0 ;
Cld ;
Stosw ;
Iret ; Back!!
I22:
Mov Ax,Es_Selector ;
Mov Es,Ax ; Make the screen acessable
Mov Al,'T' ; Int number calling
Mov Ah,7 ;
Mov Di,0 ;
Cld ;
Stosw ;
Iret ; Back!!
I23:
Mov Ax,Es_Selector ;
Mov Es,Ax ; Make the screen acessable
Mov Al,'V' ; Int number calling
Mov Ah,7 ;
Mov Di,0 ;
Cld ;
Stosw ;
Iret ; Back!!
I24:
Mov Ax,Es_Selector ;
Mov Es,Ax ; Make the screen acessable
Mov Al,'W' ; Int number calling
Mov Ah,7 ;
Mov Di,0 ;
Cld ;
Stosw ;
Iret ; Back!!
I25:
Mov Ax,Es_Selector ;
Mov Es,Ax ; Make the screen acessable
Mov Al,'X' ; Int number calling
Mov Ah,7 ;
Mov Di,0 ;
Cld ;
Stosw ;
Iret ; Back!!
I26:
Mov Ax,Es_Selector ;
Mov Es,Ax ; Make the screen acessable
Mov Al,'Y' ; Int number calling
Mov Ah,7 ;
Mov Di,0 ;
Cld ;
Stosw ;
Iret ; Back!!
I27:
Mov Ax,Es_Selector ;
Mov Es,Ax ; Make the screen acessable
Mov Al,'Z' ; Int number calling
Mov Ah,7 ;
Mov Di,0 ;
Cld ;
Stosw ;
Iret ; Back!!
End_Of_Ints EQU $
Int_Seg Ends
Run_Code Segment PARA PUBLIC 'EXEC'
;=============================================================================;
; This is where control is transfered to in Prot. Mode. ;
;=============================================================================;
Assume Cs:Run_Code
Msg1 db 'Have entered protected mode',0
Initialize: Mov Ax,GDT ; Get segment of GDT table
Mov Es,Ax ; ES Contains the GDT
Mov Ds,Ax ;
Call Make_24bit ; Do it
Mov Di,Gdt_Alias_Selector ; Get the selector
Mov BaseW[Di],Dx ; Base segmemnt of GDT
Mov BaseB[Di],Al ;
Mov Ax,IDT ; The IDT setup
Call Make_24bit ;
Mov Di,Idt_Alias_Selector ; Get it
Mov BaseW[Di],Dx ;
Mov BaseB[Di],Al ;
Mov Ax,Cs ; Get the Thing here
Call Make_24bit ;
Mov Di,Main_Code_Selector ; Get this
Mov BaseW[Di],Dx ;
Mov BaseB[Di],Al ;
Lea Si,Main_Code_End ;
Mov Lim[Di],Si ; Limit on main code
Mov Di,Es_Selector ;
Mov BaseW[Di],Dx ;
Mov BaseB[Di],Al ;
Mov Lim[Di],Si ;
Mov Di,Ds_Selector ;
Mov BaseW[Di],Dx ;
Mov BaseB[Di],Al ;
Mov Lim[Di],Si ;
Mov Ax,StackSeg ;
Call Make_24bit ;
Mov Di,Ss_Selector ;
Mov BaseW[Di],Dx ;
Mov BaseB[Di],Al ;
Lea Si,TOS ;
Mov Lim[Di],Si ;
Mov Ax,Int_Seg ; Get the interrupt segment
Call Make_24bit ; Do it
Mov Di,Int_Code_Selector ;
Mov BaseW[Di],Dx ;
Mov BaseB[Di],Al ;
Lea Si,End_Of_Ints ;
Mov Lim[Di],Si ;
;
Mov Ah,89h ; Call to do it
Mov Al,0 ;
Mov Bx,40h ;
Xor Si,Si ;
Int 15h ; By By!!
Main_Program: Sti ;
Mov Di,0 ;
Lea Si,Msg1 ;
Cld ;
Mov Ah,07h ;
Tl1: Lodsb ;
Cmp Al,0 ;
Je Done ;
Stosw ;
Jmp Tl1 ;
Done: ;
;
Forever: Jmp Forever ; Loop Forever
Make_24bit PROC near
;-----------------------------------------------------------------------------;
; Makes a 24 bit address retrned in DX (The word) and Al (The byte) ;
; Receives a 16 bit num,ber in AX to convert!. ;
;-----------------------------------------------------------------------------;
Push Bx ;
Push Cx ;
Mov Dx,Ax ;
Mov Bx,0F000h ; The Mask
Mov Cl,4 ; The shift
And Ax,Bx ; The upper 4 bits here
Not Bx ; Flip
And Dx,Bx ; The lower here
Rol Ax,Cl ; Rotate (Upper byte)
Shl Dx,Cl ; This (Lower word)
Pop Cx ;
Pop Bx ;
Ret
Make_24bit Endp
InitialEntry: Jmp Initialize ; Go initialize things
Main_Code_End EQU $
Run_Code Ends
StackSeg Segment PARA STACK 'STACK'
Db 1024 DUP(0)
TOS EQU $
StackSeg ENDS
End InitialEntry
