Microsoft Programmer's Library 1.3

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/ Microsoft Programmer's Library 1.3 / Microsoft-Programers-Library-v1.3.iso / sampcode / msj / msjv4_5 / ems / emstools.asm next >

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Assembly Source File | 1989-05-08 | 23.6 KB | 794 lines

;============================================================================= ; Assembly language EMS routines ; written by Douglas Boling ; (c) 1989 Microsoft Corporation ;============================================================================= .MODEL small .DATA ems_header db "EMMXXXX0",0 ;ASCIIZ EMS driver name fun25_array dw 96 dup (0) ;Array for physical page data fun25_array_end = $ ems32up_version db 0 ;Version number for dispatcher ems32up_calltbl dw offset EMSMapMultiple dw offset EMSMapandJump dw offset EMSMapandCall .CODE PUBLIC GetEMSMem PUBLIC SaveEMSMem PUBLIC RestoreEMSMem PUBLIC FreeEMSMem PUBLIC CheckAlias PUBLIC MapbyName PUBLIC EMS32Upgrade ;============================================================================= ;GetEMSMem reserves the amount of Expanded memory requested in BX. ; Entry: BX - amount of memory to reserve ; SI - Pointer to name to assign to handle in ASCIIZ format. ; Set SI = -1 for no name. ; Exit: AL - EMM Version. ; BX - segment of page frame. ; CX - Size of page frame. ; DX - EMS handle. ;============================================================================= GetEMSMem proc push bp mov bp,sp push ax push bx push cx push dx push di push si push es ;----------------------------------------------------------------------------- ;See if EMS driver installed. ;----------------------------------------------------------------------------- call FindEMS ;See if EMM is loaded or ah,ah ;Check for error jne getp_error ; RC <> 0, error ;----------------------------------------------------------------------------- ;Reserve pages. ;----------------------------------------------------------------------------- mov bx,[bp-4] ;Get number of pages to res mov ah,43h ;EMS Allocate pages function int 67h ;Call EMS Driver or ah,ah ;Check for error jne getp_error ;If error, exit. mov [bp-8],dx ;Save handle. ;----------------------------------------------------------------------------- ;Get version. ;----------------------------------------------------------------------------- mov ah,46h ;Get Expanded Memory version int 67h or ah,ah jne getp_error mov [bp-2],al ;Save version mov dl,al ;----------------------------------------------------------------------------- ;See how many physical pages and the number of pages in the page frame. ;----------------------------------------------------------------------------- mov cx,4 ;Assume EMM ver 3.2, 4 pages mov bx,cx ;Save number of pages in frame cmp dl,40h ;Check for version 4.0 jb getp_continue ;If before 4.0, use 4 pages mov ax,5801h ;Get number of entries in the int 67h ; map array. or ah,ah ;Check for error jne getp_error mov ax,cx ;Copy number of entries sal ax,1 ;Mult number of entries by 4 sal ax,1 cmp ax,offset fun25_array_end - offset fun25_array jb getp_2 mov ah,0f2h ;Load array too large RC jmp getp_exit getp_2: mov bx,cx ;Copy number of physical pages mov ax,ds ;Set ES = DS mov es,ax mov di,offset fun25_array mov ax,5800h ;Get mappable page array int 67h ;Call driver or ah,ah jne getp_error xor ax,ax getp_loop2: cmp ax,[di+2] ;Search list for physical page je getp_3 ; zero. That is the start of add di,4 ; the page frame. loop getp_loop2 mov ah,0f3h ;Page frame not found in list. getp_error: jmp getp_exit getp_3: xor bx,bx ;Zero consecutive page count getp_loop3: inc bx ;Count the number of mov dx,[di] ; consecutive segments. add dx,1024 ;Add num of paragraphs per seg cmp dx,[di+4] ;Compare with next segment jne getp_continue ;If not consecutive, exit add di,4 ;Point to next entry loop getp_loop3 getp_continue: mov [bp-6],bx ;Put page frame size into mov cx,[bp-4] ; stack and get num of pages ;----------------------------------------------------------------------------- ;Map pages into page frame. ;----------------------------------------------------------------------------- cmp cx,bx ;See if number of pages larger jb getp_4 ; that the size of the frame. mov cx,bx ;Use the page frame size. getp_4: xor bx,bx ;Start with logical page 0 mov dx,[bp-8] ;Get back handle getp_loop4: mov al,bl ; at physical page 0 mov ah,44h ;EMS Map Page function int 67h ;Call EMS Driver or ah,ah ;Check for error jne getp_exit ;If error, exit. inc bx ;Point to next logical page loop getp_loop4 ;----------------------------------------------------------------------------- ;Get page frame segment. ;----------------------------------------------------------------------------- mov ah,41h ;EMS Get page frame segment int 67h ;Call EMS Driver or ah,ah ;Check for error jne getp_exit ;If error, exit. mov [bp-4],bx ;Save page frame segment. ;----------------------------------------------------------------------------- ;Set the handle name. ;----------------------------------------------------------------------------- xor ax,ax ;Zero return code. mov si,[bp-12] ;Get back name pointer cmp si,-1 ;if -1, no name je getp_exit mov dx,[bp-8] ;Get handle mov ax,5301h ;EMS Set Handle Name. int 67h ;Call EMS Driver or ah,ah ;Check for error jne getp_exit ;If error, exit. getp_exit: mov [bp-1],ah ;Save return code on stack pop es pop si pop di pop dx pop cx pop bx pop ax pop bp ret GetEMSMem endp ;============================================================================= ;SaveEMSMem Saves the context of EMS driver. ; Entry: CX - Size of save area in bytes. ; ES:DI - Pointer to save area ; Exit: AH - Return code ; DX - Index, Used to identify saved state. ;============================================================================= SaveEMSMem proc push bx push cx push di mov ax,4e03h ;Get save area size int 67h xor ah,ah ;Clear top byte of save size add ax,4 mov bx,di ;Copy buffer pointer cmp word ptr es:[di],4244h ;Check for initialized area je save_1 mov es:[di],4244h ;Load signature xor dx,dx mov es:[di+4],dx ;Init first index dec dx mov es:[di+2],dx ;Init queue end pointer save_1: ;----------------------------------------------------------------------------- ;Find the first free area in the save buffer. ;----------------------------------------------------------------------------- inc di inc di add cx,bx ;Add base address to size but sub cx,ax ; subtract entry size. xor dx,dx save_2: cmp dx,es:[di+2] ;Find max value of index jae save_3 ; in the queue. mov dx,es:[di+2] save_3: cmp word ptr es:[di],-1 ;If = -1 then this is the je save_4 ; last entry. add di,es:[di] ;Point to next entry jc save_areafull ;Check for end of segment and cmp di,cx ; end of buffer. ja save_areafull jmp short save_2 save_4: add di,4 ;Move past queue overhead inc dx ;Create new index. push ax mov ax,4e00h ;Save page map int 67h or ah,ah pop ax jne save_exit mov es:[di-4],ax ;Update queue pointers mov es:[di-2],dx add di,ax sub di,4 mov word ptr es:[di],-1 save_exit: pop di pop cx pop bx ret save_areafull: mov ah,8ch ;Save area full jmp short save_exit SaveEMSMem endp ;============================================================================= ;RestoreEMSMem Restore the context of EMS driver. ; Entry: DX - Index, value returned by SaveEMSMem when state saved ; DS:SI - Pointer to save area ; Exit: AH - Return code ;============================================================================= RestoreEMSMem proc pushf push cx push di push si mov ax,[si] ;Check for initialized area cmp ax,4244h jne restore_bad inc si ;Point to first entry inc si restore_1: cmp [si+2],dx ;Find index value je restore_2 cmp word ptr [si],-1 ;See if at end of queue je restore_bad add si,[si] jc restore_bad ;If overflow segment, error jmp short restore_1 restore_2: mov di,si ;Copy entry add si,4 ;Point to save array mov ax,4e01h ;Restore page map int 67h or ah,ah jne restore_exit sub si,4 add si,[di] restore_3: cmp word ptr [si],-1 je restore_4 mov cx,[di] ;Load size cld rep movsb ;Copy next entry jmp short restore_3 restore_4: mov word ptr [di],-1 restore_exit: pop si pop di pop cx popf ret restore_bad: mov ah,0a3h jmp short restore_exit RestoreEMSMem endp ;============================================================================= ;FreeEMSMem Deallocates EMS memory ; Entry: DX - handle to deallocate ;============================================================================= FreeEMSMem proc mov ah,45h ;Deallocate pages int 67h ret FreeEMSMem endp ;============================================================================= ;CheckAlias Checks for memory aliasing support by EMS driver ; Exit: AH - return code ; AL - 1 Aliasing not supported, 0 - Aliasing supported. ;============================================================================= CheckAlias proc pushf push bx push cx push dx push di mov ah,41h ;Get page frame segment int 67h or ah,ah jne chkalias_exit1 mov cx,bx ;Copy page frame ;Allocate 1 logical page mov ah,43h ;EMS Allocate page mov bx,1 int 67h or ah,ah jne chkalias_exit1 ;Map logical page to physical pages 0 and 1. mov ax,4400h ;Map to page 0 mov bx,0 ;Logical page 0 int 67h or ah,ah jne chkalias_exit mov ax,4401h ;Map to page 1 mov bx,0 ;Logical page 0 int 67h or ah,ah jne chkalias_exit ;Write pattern to physical page 0, then compare to page 1. xor bl,bl ;Clear alias flag push es mov es,cx add cx,400h push cx mov di,100h ;Point 256 bytes inside page. cld mov al,5ah ;Write to page 0 then check mov cx,8 ; for aliasing by scanning rep stosb ; for the same pattern on mov cx,8 ; page 1. pop es mov di,100h repe scasb pop es je chkalias_exit inc bl chkalias_exit: mov ah,45h ;Deallocate pages int 67h mov al,bl ;Copy alias flag chkalias_exit1: pop di pop dx pop cx pop bx popf ret chkalias_error: mov ax,8000h ;Indicate SW error jmp short chkalias_exit1 CheckAlias endp ;============================================================================= ;MapbyName Map expanded memory pages by name. ; Entry: AL - Physical page ; BX - Logical page to map. ; DS:SI - Pointer to Handle name in ASCIIZ format ; Exit: AH - Return code ; DX - EMS Handle ;============================================================================= MapbyName proc push cx mov cx,ax ;Save physical page number mov ax,5401h ;EMS find handle function int 67h ;Call EMS driver or ah,ah ;Check for error jne mbn_exit ;If error, exit mov al,cl ;Get back physical page mov ah,44h ;EMS Map page function int 67h ;Call EMS driver pop cx mbn_exit: ret MapbyName endp ;====================================================================== ; FindEMS determines if the EMM is loaded. ;====================================================================== FindEMS proc call check_ems_hdl ;Check for driver using jnc find_1 ; open handle technique rcl ah,1 ;If not enough handles, try jc find_driver_error ; interrupt technique. call check_ems_int jnc find_1 ;If manager found, continue find_driver_error: mov ah,0f1h ;Set error code. jmp short find_exit find_1: mov ah,40h ;Check status int 67h find_exit: ret FindEMS endp ;====================================================================== ; Test for EMS driver (Open Handle Technique) ;====================================================================== check_ems_hdl proc mov dx,offset ems_header mov ax,3d00h ;Open device read only. int 21h jnc cemsh_device_open cmp ah,4 ;If file or path not found, jb cemsh_not_found ; no EMS driver. mov ah,01h ;Too many open handles or jmp short cemsh_error ; access denied. cemsh_device_open: mov bx,ax ;Copy handle mov ax,4400h ;Get device information. int 21h jc cemsh_not_foundclose test dx,80h ;Test file/device bit je cemsh_not_foundclose ;0 = file not device mov ax,4407h ;Get output status int 21h jc cemsh_not_foundclose ;If error, no device cmp al,0ffh ;Check for ready status jne cemsh_not_foundclose ;If not ready, no device mov ah,3eh ;Close handle int 21h ;BX contains handle clc cemsh_exit: ret cemsh_not_foundclose: mov ah,3eh ;Close handle int 21h ;BX contains handle cemsh_not_found: mov ah,81h ;Not found error code cemsh_error: stc jmp short cemsh_exit check_ems_hdl endp ;====================================================================== ; Test for EMS driver (Get Interrupt technique) ;====================================================================== check_ems_int proc push es ;Test for ems driver push di mov ax,3567h ;Get EMS vector int 21h mov di,0ah ;Using the segment from the mov si,offset ems_header ; 67h vector, look at offset mov cx,8 ; 0ah. Compare the next 8 cld ; bytes with the expected repe cmpsb ; EMS header. If they are pop di ; the same, EMS driver pop es ; found. jne cemsi_error clc cemsi_exit: ret cemsi_error: stc jmp short cemsi_exit check_ems_int endp ;============================================================================= ;EMS32Upgrade ; Entry: AX - EMS 4.0 compatible function number ; Other registers configured as needed by the fucntion ; Exit: AH - Return code ;============================================================================= EMS32Upgrade proc far pushf push bp mov bp,sp push ax ;Save function number mov al,EMS32up_version ;Get version or al,al ;See if initialized jne ems32_2 ;Yes, version already found mov ah,46h ;EMS Get Version int 67h ;Call EMM or ah,ah ;Check for error jne short ems32_exit mov EMS32up_version,al ;Set version ems32_2: cmp al,40h ;Check for version 4.0 je ems32_call_driver cmp al,32h ;Check for version 3.2 je ems32_3 mov ah,0ffh ;Set bad version error code jmp short ems32_exit ems32_3: mov ax,[bp-2] ;Get function number cmp ah,4eh ;See if function 1 to 15 jbe ems32_call_driver ;If so, call EMM push bx mov bx,offset ems32_return push bx ;Put return address on stack mov bx,ax ;Convert function into mov bl,bh ; jump table index. xor bh,bh sub bl,50h or bl,bl je ems32_4 sub bl,4 cmp bl,2 jbe ems32_4 mov ah,84h ;Unsupported function code jmp short ems32_exit ems32_4: shl bx,1 add bx,offset ems32up_calltbl push [bx] ;Push subroutine addr on stack mov bx,[bp-4] ;Get original BX retn ;Call function ems32_return: add sp,2 ;Pull BX off stack jmp short ems32_exit ems32_call_driver: mov ax,[bp-2] ;Restore AX cmp ah,55h ;See if map and jump jne ems32_5 ;If so, clean up stack since add sp,2 ; EMM will not return to mov [bp+4],ax ; this routine. mov ax,[bp+2] ;Use AX and flags values to mov [bp+6],ax ; overwrite return address. pop bp pop ax ;Clean off extra flags reg pop ax ;Get back AX popf ;Restore Flags ems32_5: int 67h ;Call EMM ems32_exit: add sp,2 ;Clear off original AX pop bp popf ret ;============================================================================= ;EMSMapMultiple simulates the Map Multiple function of the EMS 4.0 driver. ; Entry: AL - subfunction. 0 = Use physical page numbers ; 1 = Use physical page segments ; CX - Size of mapping array ; DX - EMS Handle ; DS:SI - Pointer to array of mapping structures (1 structure per page) ; Exit: AH - Return code ; ; Page mapping structure: ; log_to_phys_struc STRUC ; log_page_number dw ? ; phy_page_number dw ? ; log_to_phys_struc ENDS ;============================================================================= mapm_pfp equ [bp-2] ;Pointer to page frame EMSMapMultiple proc push bp mov bp,sp sub sp,2 ;Create room for local var push bx push cx push di push si cmp al,1 ;Check for legal subfunction jbe mapm_1 mov ah,8fh ;Subfunction code invalid jmp short mapm_exit mapm_1: xor ah,ah ;Clear return code. or cx,cx ;See if mapping 0 pages je mapm_exit ;If so, exit. xor ah,ah mov di,ax ;Copy subfunction mov ah,41h ;EMS Get Page Frame segment int 67h ;Call EMS driver or ah,ah ;Check for error jne mapm_exit mov mapm_pfp,bx ;Save page frame pointer mapm_loop1: mov ax,[si+2] ;Get physical page or di,di ;See if map by segment or num je mapm_4 sub ax,mapm_pfp ;Sub starting addr of frame jae mapm_3 ;If positive, continue mapm_2: mov ah,8bh ;Page segment illegal RC jmp short mapm_exit ;Error, goto exit mapm_3: push dx ;Save handle xor dx,dx ;Clear high word mov bx,400h ;Divide by segment size div bx or dx,dx ;Check for remainder. If found pop dx ; the segment was not on a jne mapm_2 ; proper boundry. mapm_4: mov bx,[si] ;Get logical page mov ah,44h ;EMS Map page int 67h ;Call EMS driver or ah,ah ;Check for error jne mapm_exit add si,4 loop mapm_loop1 mapm_exit: pop si pop di pop cx pop bx add sp,2 pop bp ret EMSMapMultiple endp ;============================================================================= ;EMSMapandJump Simulates the Map and Jump function of the EMS 4.0 driver. ; Entry: AL - Subfunction. 0 = Use physical page numbers ; 1 = Use physical page segments ; DX - EMS Handle ; DS:SI - Pointer to map and jump structure ; Exit: AH - Return code ; ; Map and Jump structure: ; map_and_jump_struc STRUC ; target_addr dd ? ; log_phys_map_len db ? ; log_phys_map_ptr dd ? ; map_and_jump_struc ENDS ; ; Page mapping structure: ; log_phys_map_struc STRUC ; log_page_number dw ? ; phy_page_number dw ? ; log_phys_map_struc ENDS ;============================================================================= EMSMapandJump proc push bx push cx push si push ds xor cx,cx ;Clear size mov cl,ds:[si+4] ;Get size of map array lds si,ds:[si+5] ;Get pointer to map array call EMSMapMultiple ;Call MapMultiple to map pages or ah,ah ;Check for error pop ds pop si pop cx pop bx jne mapandjump_exit ;If so, error code in AH. Exit mov ax,ds:[si] ;Copy jump address over return mov [bp+4],ax ; address on the stack. mov ax,ds:[si+2] mov [bp+6],ax xor ax,ax ;Zero return code. mapandjump_exit: ret EMSMapandJump endp ;============================================================================= ;EMSMapandCall Simulates the Map and Call function of the EMS 4.0 driver. ; Entry: AL - Subfunction. 0 = Use physical page numbers ; 1 = Use physical page segments ; 2 = Get Stack space size ; DX - EMS Handle ; DS:SI - Pointer to map and call structure ; Exit: AH - Return code ; ; Map and Call structure: ; map_and_call_struc STRUC ; target_addr dd ? ; new_page_map_len db ? ; new_page_map_ptr dd ? ; old_page_map_len db ? ; old_page_map_ptr dd ? ; map_and_call_struc ENDS ; ; Page mapping structure: ; log_phys_map_struc STRUC ; log_page_number dw ? ; phy_page_number dw ? ; log_phys_map_struc ENDS ;============================================================================= EMSMapandCall proc push ax mov ax,4e03h ;Get size of save array int 67h or ah,ah pop bx ;Get back function jne mac_0 cmp bl,2 ;Check for subfunction 2 jne mac_1 add al,24 ;Add aditional room on stack mac_0: jmp mac_exit1 ; on the stack. mac_1: push si ;Save array pointer push ds push di ;Save registers needed for push es ; save page map call sub sp,ax ;Create room on stack mov di,ss ;Point to save area on stack mov es,di mov di,sp push ax ;Save size of save area mov ax,4e00h ;Save page map int 67h ;Call EMM or ah,ah je mac_2 mac_save_error: pop di ;Get save area size add sp,di ;Remove save area from stack jmp short mac_exit mac_2: mov ax,[bp-2] ;Get original AX for push cx ; subfunction. xor cx,cx ;Clear size mov cl,ds:[si+4] ;Get size of new array lds si,ds:[si+5] ;Get pointer to new map array call EMSMapMultiple ;Call MapMultiple to map pages pop cx mov ds,[bp-10] mov si,[bp-8] ;Restore registers or ah,ah ;Check for error jne mac_save_error ;If so, error code in AH. mov es,[bp-14] mov di,[bp-12] mov ax,[bp+2] ;Get flags off stack push ax popf ;Restore flags push bp ;Save my BP mov bp,[bp] ;Restore original BP mov ah,0 ;Set return code call dword ptr ds:[si] ;Call user routine pop ax ;Get back BP used by routine xchg bp,ax ;Put returned BP on stack in mov [bp],ax ; place of original BP pushf ;Put all 16 bits of the flags pop ax ; register in AX. mov [bp+2],ax ;Save new flag state on stack mov [bp-12],di ;Save new ES:DI mov [bp-14],es mov di,si ;Save new DS:SI push ds pop es mov si,ss ;Point to save area on stack mov ds,si mov si,sp inc si ;Move past save area size inc si mov ax,4e01h ;Restore page map int 67h pop si ;Get size of save area add sp,si ;Remove save area from stack push es pop ds mov si,di or ah,ah jne mac_exit push cx ;Save working registers push si push ds mov si,[bp-8] ;Get pointer to structure off mov ds,[bp-10] ; the stack xor cx,cx ;Clear size mov ax,[bp-2] ;Restore subfunction mov cl,ds:[si+9] ;Get size of old array lds si,ds:[si+10] ;Get pointer to old map array call EMSMapMultiple ;Call MapMultiple to map pages pop ds pop si pop cx mac_exit: pop es pop di add sp,4 ;Clear off old SI and DS mac_exit1: ret EMSMapandCall endp EMS32Upgrade endp end