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Assembly Source File | 1992-02-20 | 19.6 KB | 544 lines

;--------------------------------------------------------------- ;ioinit - main module for I/O Monitor | ;--------------------------------------------------------------| ;Copyright 1991 ASMicro Co. | ;--------------------------------------------------------------| ; 5/19/91 Rick Knoblaugh | ;--------------------------------------------------------------| ;include files | ;--------------------------------------------------------------- .386P include ioequ.inc include iostruc.inc include iomac.inc include iodat.inc ;-------------------------------------------------------------- ;EXTERNALS | ;-------------------------------------------------------------- isrcode segment para public 'icode16' use16 extrn int_0:far extrn int_2:far extrn int_3:far extrn int_4:far extrn int_5:far extrn int_6:far extrn int_7:far extrn except_8:far extrn except_9:far extrn except_0ah:far extrn except_0bh:far extrn except_0ch:far extrn except_0dh:far extrn except_0eh:far extrn except_0fh:far extrn int_20h:far extrn int_21h:far extrn int_22h:far extrn int_23h:far extrn int_24h:far extrn int_25h:far extrn int_26h:far extrn int_27h:far extrn int_70h:far extrn int_71h:far extrn int_72h:far extrn int_73h:far extrn int_74h:far extrn int_75h:far extrn int_76h:far extrn int_77h:far extrn int1_isr:far extrn user_int_isr:far isrcode ends assume cs:code, ds:nothing, es:nothing code segment para public 'code16' use16 assume cs:code, ds:data, es:data .8086 start proc far push ds ;save psp seg mov ax, data mov es, ax call get_args ;get io ports mov ax, data mov ds, ax jnc start_100 ;continue if args ok start_050: mov ah, DOS_PRT_STRING int 21h mov ax, 4c01h int 21h start_100: call verify_cpu jc start_050 ;continue if 386/486 in real mode .386P start_200: call setup_ints ;take over user int call init_gdt call init_tss mov ax, data mov ds, ax assume ds:data cli ;no ints until protected mode mov ax, gdt_seg movzx eax, ax shl eax, 4 mov gdtadrs, eax mov ax, idt_seg movzx eax, ax shl eax, 4 mov idtadrs, eax call reprogram_pic lgdt gdtl lidt idtl mov dx, iostack3 ;get stack segment mov bx, sp ;and pointer mov eax, cr0 or eax, 1 ;turn on protected mode bit mov cr0, eax ;go into protected mode ; ;jump to clear prefetch queue ; db 0eah ;far jump dw offset code:start_400 dw gdt_seg:sel_code start_400: mov ax, offset gdt_seg:sel_tss ltr ax xor ax, ax lldt ax ;null ldt mov ax, seg data movzx eax, ax push eax ;null gs push eax ;null fs push eax ;null ds push eax ;null es push 0 push dx ;stack segment push 0 push bx ;stack pointer push 2 ;VM bit set in upper eflags push 3000h ;NT=0, IOPL=3, CLI in lower eflags push 0 push seg code ;cs of where to return push 0 push offset code:start_500 ;ip of where to return ; ;Must ensure that Nested Task bit is not set in eflags. If it were, ;processor would attempt to switch to a task via the selector in ;the TSS backlink field. Since that field is now zero, an invalid TSS ;fault would occur. ; pushf pop ax and ax, NOT NT_FLAG push ax popf iretd start_500: ;begin vm86 task here pop bx ;get saved psp seg sti ;interrupts ok now mov dx, code + 1 ;init code we are dropping sub dx, bx mov al, OK ;exit code mov ah, DOS_TSR_FUNC int 21h start endp reprogram_pic proc near in al, 21h mov ah, al mov al, 11h ;init out 20h, al mov al, 20h ;irq0 to int 20h out 21h, al jmp short $ + 2 jmp short $ + 2 mov al, 4 out 21h, al jmp short $ + 2 jmp short $ + 2 mov al, 1 out 21h, al jmp short $ + 2 jmp short $ + 2 mov al, ah out 21h, al ret reprogram_pic endp .8086 ;-------------------------------------------------------------- ;get_args - retrieve starting and ending i/o addresses from | ; the command line. | ; | ; Enter: ds=PSP seg | ; | ; Exit: If invalid, carry set and dx=offset msg | ;-------------------------------------------------------------- get_args proc near cld xor si, si sub ch, ch mov cl, [si].arg_len ;get cmd line length lea si, [si].arg_off ;and offset call skip_white_sp mov dx, offset es:bad_arg_msg jcxz get_a800 ;if no args call get_validate ;get first i/o port jc get_a999 mov es:start_port, bx ;save it call skip_white_sp jcxz get_a800 ;if no 2nd arg call get_validate ;get 2nd i/o port jc get_a999 mov es:end_port, bx ;save it cmp bx, es:start_port ;2nd arg >= 1st arg jae get_a900 mov dx, offset es:bad_2nd_msg get_a800: stc jmp short get_a999 get_a900: clc get_a999: ret get_args endp ;-------------------------------------------------------------- ;get_validate - Retrieve and validate an ASCII hex number. | ; | ; Enter: si ptr to data | ; cx max len | ; | ; Exit: data at si now binary | ; cx decremented by length of number | ; If invalid, carry set and dx=&err_msg | ; bx=binary value of number | ;-------------------------------------------------------------- get_validate proc near xor bx, bx get_v100: cmp byte ptr [si + bx], ' ' je get_v200 cmp byte ptr [si + bx], CR je get_v200 inc bx jmp short get_v100 get_v200: sub cx, bx ;cmd line chars left push cx mov cx, bx xor bx, bx get_v300: sub ah, ah lodsb ;get a digit call asc2bin ;validate and convert jc get_v900 ;exit if invalid push cx jcxz get_v500 dec cx ;position from right - 1 shl cl, 1 shl cl, 1 shl ax, cl ;get nibble into position get_v500: or bx, ax ;build number pop cx loop get_v300 clc ;ok get_v900: pop cx ret get_validate endp asc2bin proc near cmp al, 'a' jb asc2b_100 and al, 0dfh ;force to upper case asc2b_100: cmp al, '0' jb asc2b_800 cmp al, '9' ;see if 0-9 or A-F ja asc2b_500 sub al, '0' ;convert to binary jmp short asc2b_600 asc2b_500: cmp al, 'F' ja asc2b_800 sub al, 'A' - 10 asc2b_600: clc jmp short asc2b_900 asc2b_800: mov dx, offset es:bad_arg_msg stc asc2b_900: ret asc2bin endp skip_white_sp proc near cmp byte ptr [si], ' ' je skip_w200 cmp byte ptr [si], TAB je skip_w200 jmp short skip_w900 skip_w200: inc si loop skip_white_sp skip_w900: ret skip_white_sp endp verify_cpu proc near xor ax,ax push ax popf pushf pop ax and ax,0f000h cmp ax,0f000h jz verify_c800 ;not 386 mov ax, 0f000h push ax popf pushf pop ax and ax,0f000h ;not 386 jz verify_c800 mov dx,offset noprot_msg .386P smsw ax ;get pm flag into carry rcr ax,1 jmp short verify_c999 verify_c800: mov dx, offset not386_msg stc verify_c999: ret verify_cpu endp setup_ints proc near mov bx, USER_INT mov di, offset old_user_int mov cx, isrcode mov dx, offset isrcode:user_int_isr call get_int ret setup_ints endp ;-------------------------------------------------------------- ;get_int - For a given interrupt vector, store contents and | ; load with new isr address. | ; | ; bx = int number | ; es:di = location to store contents | ; dx = offset new isr | ; cx = cs of new isr ;-------------------------------------------------------------- get_int proc near cld push ds xor ax, ax mov ds, ax shl bx, 2 mov ax, [bx] stosw mov ax, [bx].d_segment stosw cli mov [bx].d_offset, dx mov [bx].d_segment, cx sti pop ds ret get_int endp init_gdt proc near mov ax, gdt_seg mov ds, ax assume ds:gdt_seg mov dx, tss_seg movzx edx, dx ;base data segment mov ecx, (TSS_END - TSS_BEG ) - 1 ;limit mov ah, TSS_DESC mov si, offset sel_tss call make_entry mov dx, tss_seg movzx edx, dx ;base data segment mov ecx, (TSS_END - TSS_BEG ) - 1 ;limit mov ah, RW_DATA ;alias as r/w for editing mov si, offset sel_tss_alias call make_entry mov dx, gdt_seg movzx edx, dx ;base data segment mov ecx, (GDT_END - GDT_BEG ) - 1 ;limit mov ah, RW_DATA ;alias as r/w for editing mov si, offset sel_gdt_alias call make_entry mov dx, isrcode movzx edx, dx ;base of isr code segment mov ecx, 0ffffh ;max segment size mov ah, ER_CODE mov si, offset sel_isrcode call make_entry mov dx, code movzx edx, dx ;base code segment mov ecx, 0ffffh ;max segment size mov ah, ER_CODE mov si, offset sel_code call make_entry xor edx, edx ;zero base mov ecx, 0fffffh ;base memory size mov ah, RW_DATA mov si, offset sel_databs call make_entry mov dx, iostack movzx edx, dx ;base stack segment mov ecx, (STACK_END - STACK_BEG ) - 1 ;limit mov ah, RW_DATA mov si, offset sel_stack call make_entry mov dx, data movzx edx, dx ;base data segment mov ecx, (DATA_END - DATA_BEG ) - 1 ;limit mov ah, RW_DATA mov si, offset sel_data call make_entry int 11h ;equipment check mov edx, 0b800h ;color segment and al, 30h ;monitor bits cmp al, 30h ;30h=monochrome jne init_gdt500 mov edx, 0b000h ;monochrome segment init_gdt500: mov ecx, VID_PAGE_SIZE - 1 ;page size - 1 mov ah, RW_DATA mov si, offset sel_video call make_entry ret init_gdt endp ;-------------------------------------------------------------- ;make_entry - Load a GDT entry from information passed as | ; follows: | ; | ; ds=gdt segent | ; si=offset of gdt entry to load | ; ah=type | dpl | ; ecx=limit | ; edx=base segment (convert it to linear) | ; Always set for byte granularity and 16 bit size | ; | ;-------------------------------------------------------------- make_entry proc near shl edx, 4 ;convert seg to linear mov [si].seg_limit_low, cx mov [si].seg_base_low, dx shr edx, 16 mov [si].seg_base_mid, dl mov [si].seg_type_dpl, ah shr ecx, 16 and cl, 0fh ;limit and byte gran mov [si].seg_limit_gran, cl mov [si].seg_base_top, dh ret make_entry endp ;-------------------------------------------------------------- ;init_tss - Initilize TSS with base of I/O bit map and set | ; appropriate bits in I/O bit map per cmd line. | ; | ;-------------------------------------------------------------- init_tss proc near mov ax, tss_seg mov ds, ax assume ds:tss_seg xor si, si mov ax, offset gdt_seg:sel_stack mov [si].t_ess0, ax mov ax, offset iostack:io_sp movzx eax, ax mov [si].t_esp0, eax lea bx, [si].t_iomap mov [si].t_iobase, bx mov cx, es:start_port ;start of range to monitor mov dx, cx and cl, 7 ;get non byte boundary mov al, 1 ;first bit position shl al, cl ;get out corresponding bit shr dx, 3 ;start_port/8 mov cx, es:end_port sub cx, es:start_port inc cx add bx, dx ;starting offset in map init_t100: or byte ptr [bx], al ;turn on permission bit rcl al, 1 ;next bit position jnc init_t300 inc bx rcl al, 1 init_t300: loop init_t100 ret init_tss endp code ends end start