dosexe.asm

操作系统完整源代码大机密!

;程序文件：\TC\G\DOSEXE_P.ASM 清单
.MODEL HUGE
.386P
include \tc\g\include\g_def.asm   ; 描述符结构、常量、宏定义,清单见程序1-1
include \tc\g\include\tos_seg.asm ; 定义TOS堆栈段TOS_STACKSEG与TOS任务状态段TOS_TSSSEG
                                  ; 清单见程序1-2
include \tc\g\include\ps_seg.asm  ; U.EXE任务的各段：堆栈段、任务状态段、LDT表
TOS_CODESEG SEGMENT PARA USE16    ; TOS操作系统的代码段
            ASSUME CS:TOS_CODESEG,DS:DATA,SS:TOS_STACKSEG
TOS_BEGIN:   
            TOS_BEGIN0            ; TOS任务初始处理，在包含\tc\g\include\g_def.asm文件中
;JMP TURN_TO_REAL_MODE 
            MOV CX,08D0H          ; 清屏
            MOV BX,0              ;ds:tos_data fs:data
scr1:       MOV ES:[BX],0720H
            ADD BX,2
            LOOP scr1
;JMP TURN_TO_REAL_MODE 
            call disp_TOS_in_tos  ; 显示U.EXE的LDT表和开头部分内容，本书未给清单
;JMP TURN_TO_REAL_MODE 
            MOV AH,9              ; 显示"This is a protect_mode program!"
            MOV CX,0205H ;15 row 21 column
            MOV DX,OFFSET TEST_MSG
            INT 21H

;JMP TURN_TO_REAL_MODE 

            MOV BX,USER_PsLDT_SEL
            LLDT BX
            ;*** 将c_buffer(放U.EXE)中内容? g_buf
            MOV ECX,0
            MOV CX,FS:C_BUF_SIZE
            MOV EAX,OFFSET C_BUFFER
            MOV ESI,EAX
            MOV EDI,DS:G_BUF_SUM

MOVE_BUF1:  MOV AL,FS:[ESI]        ;移到g_buf，C_BUF_SIZE：文件大小 
            MOV GS:[EDI],AL
            INC EDI
            INC ESI
            LOOP MOVE_BUF1
            ;**********************开始处理 U.EXE
            MOV AX,TOS_DATA_SEL
            MOV DS,AX             ;TOS系统数据段
            MOV AX,G_BUF_SEL      
            MOV GS,AX             ;.exe(g_buf) 段，EXE头+程序
            MOV AX,USER_PS_SEL    ;GDT中USER_PS的首址
            SUB AX,04H
            CALL G_EXEC           ;重定位，创建段表，开始2字节<>4D5AH，则不是DOS .exe 
;JMP TURN_TO_REAL_MODE 
            CMP AX,1              ; 
            JZ  ERR_EXEFIL
            ;**********************设置U.EXE的任务状态段 
            MOV BL,DS:G_WORK[4]
            MOV BH,DS:G_WORK[5]
            MOV CL,DS:G_WORK[6]
            MOV CH,DS:G_WORK[7]
            push fs
            mov ax,USER_PsTSS_D_SEL
            mov fs,ax
            mov fs:USER_Ps_TASK.TREIP,cx
            mov fs:USER_Ps_TASK.TREIP+2,0
            mov fs:USER_Ps_TASK.TRCS,USER_PS_SEL
;此处略去：显示U.EXE的代码段选择子与ip 的程序，请见光盘
            ;;;;;disp cs ip   disable in book
            mov ax,cx
            mov cx,0E16H
            call disp_ax
            MOV AH,9
            MOV CX,0E10H ;15 row 21 column
            MOV DX,OFFSET TEST_IP     ;"IP: "
            INT 21H
            MOV AH,9
            MOV CX,0E00H ;10 row 00 column
            MOV DX,OFFSET TEST_CS     ;"CS: "
            INT 21H
            mov ax,user_ps_SEL
            mov cx,0E06H
            call disp_ax
            ;;;;;disp cs ip   disable in book

            mov fs:USER_Ps_TASK.TRCS+2,0
            mov fs:USER_Ps_TASK.TREFLAG,0
            mov fs:USER_Ps_TASK.TRLDT,USER_PsLDT_SEL
            mov fs:USER_Ps_TASK.TRLDT+2,0
            mov fs:USER_Ps_TASK.trcr3,0
            mov al,ds:g_WORK

            mov ah,ds:g_WORK[1]
            mov fs:USER_Ps_TASK.TRDS,14h
            mov fs:USER_Ps_TASK.TRDS+2,0
            mov fs:USER_Ps_TASK.TRES,G_VRAM_SEL
            mov fs:USER_Ps_TASK.TRES+2,0
            mov fs:USER_Ps_TASK.TRSS0,AX
            mov fs:USER_Ps_TASK.TRSS0+2,0
            mov fs:USER_Ps_TASK.TRSS,AX
            mov fs:USER_Ps_TASK.TRSS+2,0
            mov al,ds:g_WORK[2]
            mov ah,ds:g_WORK[3]
            mov fs:USER_Ps_TASK.TRESP0,AX
            mov fs:USER_Ps_TASK.TRESP0+2,0
            mov fs:USER_Ps_TASK.TRESP,AX
            mov fs:USER_Ps_TASK.TRESP+2,0
            mov fs:USER_Ps_TASK.TRFLAG,0
            pop fs
            call disp_ldt_head       ; 显示U.EXE的LDT表和重定位后的开头部分，在
; \tc\g\include\reposit.asm中，本书中未给出该过程的程序，请见光
;盘 

            DB 0EAH                  ;通过U.EXE的任务状态段，执行U.EXE
            DW 0 
            dw USER_PsTSS_SEL
COMEBACK_TO_TOS:
            JMP TURN_TO_REAL_MODE 
ERR_EXEFIL:
            MOV AH,9
MOV CX,1100H 
MOV DX,OFFSET ERR_EXEFILE
            INT 21H    
TURN_TO_REAL_MODE:
            call turn_to_real                  ;返回实模式，在\tc\g\include\tos_used.asm
;中
            include \tc\g\include\tos_used.asm ;
            include \tc\g\include\reposit0.asm  ;
TOS_CODELEN = $
TOS_CODESEG ENDS

GDTSEG      SEGMENT PARA USE16              ;全局描述符表
GDT         LABEL BYTE
G_NULL      GDT_DESC <>
REAL_SEG    GDT_DESC <0FFFFH,0,0,92H,0,0>
REAL_SEL    = REAL_SEG - GDT
GDT_INIT_BEGIN LABEL BYTE
TOS_CODE    GDT_DESC <0FFFFH,TOS_CODESEG,0,9AH,0,0> ;9AH=exec/read ,DPL=0
            ;limit must be 0ffffh for returnning to real_mode
TOS_CODE_SEL = TOS_CODE - GDT
TOS_DATA    GDT_DESC <DATA_TOSLEN,DATA_TOS,0,92H,0,0> ;92H=P ,DPL=0,TYPE=2
TOS_DATA_SEL = TOS_DATA - GDT
TOS_STACK   GDT_DESC <TOS_STACKLEN,TOS_STACKSEG,0,93H,0,0>   ;96H=R/W ,DOWN
TOS_STACK_SEL = TOS_STACK - GDT
TOS_TSS     GDT_DESC <TOS_TSSLEN,TOS_TSSSEG,0,089H,0,0> ;89H=386TSS DPL=0
TOS_TSS_SEL  = TOS_TSS - GDT
USER_PsTSS     GDT_DESC <USER_PsTSSLEN,USER_PsTSSSEG,0,089H,0,0> ;9AH=exec/read ,DPL=0
USER_PsTSS_SEL  = USER_PsTSS - GDT
USER_PsTSS_D     GDT_DESC <USER_PsTSSLEN,USER_PsTSSSEG,0,92H,0,0> ;9AH=exec/read ,DPL=0
USER_PsTSS_D_SEL  = USER_PsTSS_D - GDT
USER_PsLDTT     GDT_DESC <USER_PsLDTLEN,USER_PsLDTSEG,0,82H,0> ;82H=LDT
USER_PsLDT_SEL = USER_PsLDTT - GDT
GDT_ASDATA  GDT_DESC <GDTLEN,GDTSEG,0,92H,0,0>
IDT         GDT_DESC <IDTLEN,IDTSEG,0,92H,0,0> ;92H=P ,DPL=0,TYPE=2
IDT_SEL     =  IDT - GDT
GDT_ASDATA_SEL = $ - GDT
USER_PsLDTT_ASDATA  GDT_DESC <USER_PsLDTLEN,USER_PsLDTSEG,0,92H,0,0>
USER_PsLDTt_ASDATA_SEL = USER_PsLDTT_ASDATA - GDT ;+ 04H
DATASEG     GDT_DESC <DATALEN,DATA,0,92H,0,0> ;92H=P ,DPL=0,TYPE=2
DATA_SEL    = DATASEG - GDT
GDT_INIT_COUNT  = ($ - GDT_INIT_BEGIN)/(SIZE GDT_DESC)
G_VRAM      GDT_DESC <0FFFFH,08000H,0BH,92H,0,0>   ;92H=P ,DPL=0,TYPE=2
G_VRAM_SEL   =  G_VRAM - GDT  ;60h
G_BUF       GDT_DESC <0FFFFH,0,40H,92H,0,0> ;92H=P ,DPL=0,TYPE=2 ,base=4M
G_BUF_SEL    = G_BUF - GDT
V_TOS_CODE_SEL = $
V_TOS_DATA_SEL = $
GDTLEN      = $ - GDT
GDTSEG      ENDS
            include \tc\g\include\COS_DATA.asm
            include \tc\g\include\COS_IDT0.asm
;*************************************************TOS above
CODE        SEGMENT PARA USE16 ;PUBLIC 'CODE'  ;实模式代码段
            ASSUME CS:CODE,DS:DATA,SS:STACK
            include \tc\g\include\a20.asm      ;见程序1-1
MAIN        PROC FAR
START:      
            REAL_BEGIN_PAGE  ;*******         ;在\tc\g\include\g_def.asm中，见程序1-1
            call g_input_file                  ;输入文件名,并将文件取到缓冲区c_buf,在
; \tc\g\include\g_real.asm中，见程序1-2
TURN_TO_PROTECT_MODE:
            CALL GDT_INIT       ;初始化GDT表，在\tc\g\include\g_real.asm中，见程序1-2
            CALL USER_Ps_LDT_INIT  ;初始化LDT表，在\tc\g\include\ps_ldt.asm中
TURN_TO_PROTECT_PAGE  ;*****进入TOS任务，在\TC\G\INCLUDE\G_DEF.ASM中，见程序1-1
REAL_MODE:  
TO_DOS                 ;回到DOS 在\TC\G\INCLUDE\G_DEF.ASM中，见程序1-1
MAIN        ENDP
include \tc\g\include\g_real.asm
include \tc\g\include\ps_ldt.asm
CODE        ENDS
include \tc\g\include\DOS_DATA.asm
            END START