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Assembly Source File | 1989-04-05 | 77KB | 2,128 lines

;============================================================================ ;EMS40.SYS an Expanded Memory Simulator for the IBM AT ;============================================================================ PAGE ,132 CODE SEGMENT PUBLIC'code' ASSUME CS:CODE ;----------------------------------------------------------------------------- ;Structure of the device driver request header ;----------------------------------------------------------------------------- REQ_STRUC STRUC LEN DB ? UNIT DB ? ;unit number COMMAND DB ? ;command code STATUS DW ? ;return status RESERVE DB 8 DUP (?) MEDIA DB ? ADDRESS DD ? ;Transfer address CONFIG_PTR DD ? ;Pointer to line in config REQ_STRUC ENDS ;----------------------------------------------------------------------------- ;Segment descriptor structure ;----------------------------------------------------------------------------- DAT_SEG_DES STRUC ;data segment descriptor SEG_LIM DW 0 ;length of segment BASE_ADRL DW 0 ;base address of segment BASE_ADRH DB 0 DB 0 ;access rights byte DW 0 ;reserved DAT_SEG_DES ENDS ;============================================================================= ;Device header begin ;============================================================================= ORG 0 ;drivers start at offset 0 HEADER DD -1 ;Pointer to next driver DW 8000H ;device attribute word DW OFFSET STRATEGY ;pointer to strategy routine DW OFFSET INTERRUPT ;pointer to interrupt routine DB 'EMMXXXX0' ;name of driver ;Device header end SWAP_POINTER DW OFFSET EMS_EXCH_PAG PROGRAM DB "EMS 4.0 Simulator" COPYRIGHT DB " (C) 1989 Ziff Communications",13,10 PROGRAMMER DB "PC Magazine ",254," Douglas Boling",13,10,"$",26 REQ_HEADADR DD ? ;Far pointer to request header ;----------------------------------------------------------------------------- ;Global Descriptor table needed for moves to and from extended memory. ;----------------------------------------------------------------------------- GDT LABEL BYTE DAT_SEG_DES <> ;Dummy DAT_SEG_DES <> ;GDT descriptor SOURCE DAT_SEG_DES <4000H,,,93H,> ;source descriptor DEST DAT_SEG_DES <4000H,,,93H,> ;destination descriptor DAT_SEG_DES <> ;bios code descriptor DAT_SEG_DES <> ;stack segment descriptor ;============================================================================= ;Strategy routine. This routine stores the address of the request header ;============================================================================= STRATEGY PROC FAR ASSUME CS:CODE,DS:NOTHING,ES:NOTHING MOV WORD PTR CS:[REQ_HEADADR],BX ;save offset MOV WORD PTR CS:[REQ_HEADADR+2],ES ;save segment RET STRATEGY ENDP ;============================================================================= ;Interrupt routine. This routine executes the command code in the req header. ;============================================================================= INTERRUPT PROC FAR ASSUME CS:CODE,DS:NOTHING,ES:NOTHING PUSHF PUSH AX ;save every register used PUSH BX PUSH CX PUSH DX PUSH DI PUSH SI PUSH DS PUSH ES PUSH CS ;Set DS POP DS ASSUME DS:CODE CLD ;any string operations move up. ;Get command from request header LES DI,[REQ_HEADADR] ;load address of req header ASSUME ES:NOTHING MOV BL,ES:[DI.COMMAND] CMP BL,0 JNE PROCESS1 CALL INITIALIZE JMP SHORT DONE PROCESS1: CMP BL,16 ;see if command out of range JBE DONE MOV AX,8003H ;unknown command error code DONE: OR AX,0100H ;set the 'done' bit MOV ES:[DI.STATUS],AX POP ES ;restore registers before exit POP DS POP SI POP DI POP DX POP CX POP BX POP AX POPF RET INTERRUPT ENDP DRIVER_END = $ ;Last part of driver code ;====================================================================== ;EMS Driver code starts here. ;====================================================================== OLD_INT15H LABEL DWORD OLD_INT15HO DW ? ;offset of old interrupt vector OLD_INT15HS DW ? ;segment EXT_MEM_LIMIT DW 0 ;adjusted top of avail memory OS_ENABLED DB 1 ;Enable os functions 1=enabled OS_PASS_LOW DW 0 ;Operating system password. OS_PASS_HIGH DW 0 ALT_MAP_PTRS DW 0 ;Mapping pointer for funct 28 ALT_MAP_PTRO DW 0 WINDOW_SEG DW ? ;starting segment of ems win WINDOW_ADDR_BASE DD 4 DUP(0) ;address of each page EXTEND_ADRL DW ? ;base of extended memory used EXTEND_ADRH DB ? TOTAL_PAGES DW 24 ;default to 384k of exp mem. TOTAL_HANDLES DW 255 ;Default number of handles PAG_OWNER_TBL DW ? ;Pointer to page table HANDLE_ARRAY DW ? ;Pointer to handle table MAP_ARRAY_PTR DW ? ;Pointer to map array ACTIVE DB 0 ;Active flag ;====================================================================== ;Interrupt 15h routine. Intercept extended memory size determine. ;====================================================================== INT_15H PROC FAR ASSUME CS:CODE,DS:NOTHING,ES:NOTHING CMP AH,88H JE INT15_F88 JMP CS:[OLD_INT15H] INT15_F88: MOV AX,CS:EXT_MEM_LIMIT ;provide new limit CLC ;clear error flag RET 2 INT_15H ENDP ;----------------------------------------------------------------------------- ;Jump table for EMS driver commands ;----------------------------------------------------------------------------- EMS_CMDS DW OFFSET EMS_01 ;Get status DW OFFSET EMS_02 ;Get page frame seg address DW OFFSET EMS_03 ;Get unallocated page count DW OFFSET EMS_04 ;Allocate pages DW OFFSET EMS_05 ;Map/unmap handle pages DW OFFSET EMS_06 ;Deallocate pages DW OFFSET EMS_07 ;Get version DW OFFSET EMS_08 ;Save page map DW OFFSET EMS_09 ;Restore page map DW OFFSET EMS_UNSP ;reserved DW OFFSET EMS_UNSP ;reserved DW OFFSET EMS_12 ;Get handle count DW OFFSET EMS_13 ;Get handle pages DW OFFSET EMS_14 ;Get all handle pages DW OFFSET EMS_15 ;Page map functions DW OFFSET EMS_16 ;Partial page map functions DW OFFSET EMS_17 ;Map/unmap multiple hndl pages DW OFFSET EMS_18 ;Reallocate pages DW OFFSET EMS_19 ;Handle attribute DW OFFSET EMS_20 ;Handle name DW OFFSET EMS_21 ;Handle directory DW OFFSET EMS_22 ;Alter page map and jump DW OFFSET EMS_23 ;Alter page map and call DW OFFSET EMS_24 ;move/exchange memory region DW OFFSET EMS_25 ;Get mappable phys addr array DW OFFSET EMS_26 ;Hardware configuration DW OFFSET EMS_27 ;Allocate standard pages DW OFFSET EMS_28 ;Alternate map register set DW OFFSET EMS_UNSP ;Warmboot preparation DW OFFSET EMS_30 ;OS/E functions ;====================================================================== ;Interrupt 67h routine. EMS driver function dispatcher. ;====================================================================== INT_67H PROC FAR ASSUME CS:CODE,DS:NOTHING,ES:NOTHING PUSH BP MOV BP,SP ;set up stack addressing STI ;allow interrupts CLD ;any string operations move up. PUSH CX ;Save registers PUSH DI ;NOTE: Don't change the PUSH SI ; order of the register save. PUSH DS ; Many of the routines depend PUSH ES ; on the correct order. PUSH CS ;point ds to code segment POP DS ASSUME DS:CODE CMP AH,5DH ;Check for a cmd out of range JA EMS_CMD_ERR CMP AH,40H JL EMS_CMD_ERR MOV DI,OFFSET RETURN_ADDR ;Push return address onto PUSH DI ; stack. PUSH AX ;save ax SUB AH,40H ;Convert command code in AX MOV AL,AH ; into a jump address. XOR AH,AH ;Clear upper byte SAL AX,1 ;Convert to word offset ADD AX,OFFSET EMS_CMDS ;add offset of jump table MOV DI,AX ;Copy to DI POP AX ;restore AX PUSH [DI] ;Put offset of routine on stk MOV DI,[BP-4] ;Restore DI CALL EMS_CHECK_HDL ;check for valid handle in DX RETN ;Use ret to call function. RETURN_ADDR: POP ES ;Restore registers POP DS POP SI POP DI POP CX POP BP EMS_I67_EXIT: IRET EMS_CMD_ERR: MOV AH,84H ;EMS command out of range JMP SHORT RETURN_ADDR INT_67H ENDP ;====================================================================== ;Function 1. Get status. ;====================================================================== EMS_01 PROC NEAR ASSUME CS:CODE,DS:CODE,ES:NOTHING XOR AX,AX RET EMS_01 ENDP ;====================================================================== ;Function 2. Get segment address of EMS window ;====================================================================== EMS_02 PROC NEAR ASSUME CS:CODE,DS:CODE,ES:NOTHING MOV BX,WINDOW_SEG ;store starting seg of window XOR AX,AX RET EMS_02 ENDP ;====================================================================== ;Function 3. Get count of unallocated pages ;====================================================================== EMS_03 PROC NEAR ASSUME CS:CODE,DS:CODE,ES:NOTHING XOR DX,DX ;search for hndl =-1 (unaloc) DEC DX CLC ;fake 'handle ok' flag CALL EMS_13 MOV DX,TOTAL_PAGES ;Load total pages XOR AX,AX ;Clear return code RET EMS_03 ENDP ;====================================================================== ;Function 4. Get handle and allocate pages ;====================================================================== EMS_04 PROC NEAR ASSUME CS:CODE,DS:CODE,ES:NOTHING OR BX,BX ;Check for 0 page request JE EMS_04_ERR ;If so, error CALL EMS_27 ;Let function 27 do the work EMS_04_EXIT: RET EMS_04_ERR: MOV AH,89H ;attempt to allocate 0 pages JMP SHORT EMS_04_EXIT EMS_04 ENDP ;====================================================================== ;Function 5, Map / Unmap pages. ;====================================================================== EMS_05 PROC NEAR ASSUME CS:CODE,DS:CODE,ES:NOTHING PUSH BX PUSH DX JC EMS_05_EXIT ;carry set, invalid handle CMP AL,3 ;Check for physical page out JG EMS_05_ERR0 ; of range CMP BX,0FFFFH ;See if unmap page. If so, JNE EMS_05_S1 ; save current mapped page MOV BL,AL ; but don't map new page. XOR AX,AX XOR DX,DX ;DL:AX=0 indicates no map JMP SHORT EMS_05_S2 EMS_05_S1: PUSH AX ;Save physical page to map CALL EMS_LOG2PHY ;Convert page into an address POP BX ;Put phy page into BX for call JC EMS_05_EXIT ;If error, exit EMS_05_S2: CALL EMS_EXCH_PAG ;Map the page XOR AX,AX ;Clear return code EMS_05_EXIT: POP DX ;Restore registers. POP BX RET EMS_05_ERR0: MOV AH,8BH ;Physical page out of range JMP SHORT EMS_05_EXIT EMS_05 ENDP ;====================================================================== ;Function 6, Deallocate pages. ;====================================================================== EMS_06 PROC NEAR ASSUME CS:CODE,DS:CODE,ES:NOTHING PUSH BX PUSH DX JC EMS_06_EXIT ;carry set, invalid handle MOV BL,0FFH ;clear all pages CALL EMS_DEALLOC ;Deallocate memory OR DL,DL ;handle zero cannot be JE EMS_06_GOOD ; deallocated PUSH CS ;Deallocate handle POP ES ASSUME ES:CODE MOV DI,HANDLE_ARRAY MOV AX,DX ;copy handle MOV CX,9 ;convert handle to an index into MUL CX ; the handle array. ADD DI,AX XOR AL,AL ;Erase handle flag and name. REP STOSB EMS_06_GOOD: XOR AX,AX ;clear return code EMS_06_EXIT: POP DX POP BX RET EMS_06 ENDP ;====================================================================== ;Function 7. Get version number ;====================================================================== EMS_07 PROC NEAR ASSUME CS:CODE,DS:CODE,ES:NOTHING MOV AX,0040H ;store ver num and ret code RET EMS_07 ENDP ;====================================================================== ;Function 8. Save page map. ;====================================================================== EMS_08 PROC NEAR ASSUME CS:CODE,DS:CODE,ES:NOTHING PUSH BX PUSH DX JC EMS_08_EXIT ;carry set, invalid handle ;Search the mapping arrays to find an array that is empty. At the same ; time, make sure that the handle doesn't have an array currently saved. MOV SI,MAP_ARRAY_PTR ;start search of map arr lbls MOV CX,3 ;search all 3 save map arrays XOR BX,BX ;initialize free pointer EMS_08_L1: ADD SI,18 ;look at next map array CMP WORD PTR [SI],0 ;see if free JNE EMS_08_S1 MOV DI,SI ;if so, copy address JMP SHORT EMS_08_S3 EMS_08_S1: CMP [SI],DX ;see if curr hndl used before JNE EMS_08_S2 MOV AH,8DH ;handle already used for save JMP SHORT EMS_08_EXIT EMS_08_S2: LOOP EMS_08_L1 ;loop back if less than 4 times MOV AH,8CH ;no room to store page map JMP SHORT EMS_08_EXIT EMS_08_S3: PUSH CS ;point ds:si to page array POP ES ASSUME ES:CODE ;point es:di to save array MOV SI,MAP_ARRAY_PTR MOV [SI],DX ;label arrays with handle MOV CX,9 REP MOVSW XOR AX,AX ;clear return code EMS_08_EXIT: POP DX POP BX RET EMS_08 ENDP ;====================================================================== ;Function 9. Restore page map ;====================================================================== EMS_09 PROC NEAR ASSUME CS:CODE,DS:CODE,ES:NOTHING PUSH BX PUSH DX JC EMS_09_EXIT ;carry set, invalid handle ;find the saved page map in the save array. MOV SI,MAP_ARRAY_PTR MOV CX,3 EMS_09_L1: ADD SI,18 ;look at next map array CMP [SI],DX ;See if array label matches the JE EMS_09_S1 ; handle. LOOP EMS_09_L1 MOV AH,8EH ;no saved page map found JMP SHORT EMS_09_EXIT ;Now that the saved array has been found, call restore map routine. EMS_09_S1: MOV WORD PTR [SI],0 ;mark saved array as free CALL EMS_15_1 ;restore map XOR AX,AX ;clear return code EMS_09_EXIT: POP DX POP BX RET EMS_09 ENDP ;====================================================================== ;Function 12, Get Handle Count ;====================================================================== EMS_12 PROC NEAR ASSUME CS:CODE,DS:CODE,ES:NOTHING MOV DI,HANDLE_ARRAY ;point to handle array XOR BX,BX ;clear count and compare regs MOV CX,TOTAL_HANDLES ;look at all handles 0 - feh EMS_12_L1: CMP BH,[DI] ;if handle id = 0 then that JE EMS_12_S1 ; handle has not been allocated. INC BL ;Add one to open handle count EMS_12_S1: ADD DI,9 ;Move di to point to next id. LOOP SHORT EMS_12_L1 XOR AX,AX ;clear return code EMS_12_EXIT: RET EMS_12 ENDP ;====================================================================== ;Function 13 Get Handle pages ;Entry: dx = handle to search for ;Exit: ax = return code. bx = number of matches found. ;====================================================================== EMS_13 PROC NEAR ASSUME CS:CODE,DS:CODE,ES:NOTHING PUSH DI JC EMS_13_EXIT ;carry set, invalid handle MOV DI,PAG_OWNER_TBL ;point to owner table MOV CX,TOTAL_PAGES XOR BX,BX ;Clear page count EMS_13_LOOP: CMP DL,[DI] ;Compare handle to table JNE EMS_13_SKIP INC BX ;Inc count of pages EMS_13_SKIP: ADD DI,3 ;Point to next entry LOOP EMS_13_LOOP XOR AX,AX ;Clear return code. EMS_13_EXIT: POP DI RET EMS_13 ENDP ;====================================================================== ;Function 14. Get All Handle Pages ;====================================================================== EMS_14 PROC NEAR ASSUME CS:CODE,DS:CODE,ES:NOTHING PUSH DX XOR DX,DX ;handle currently being checked XOR SI,SI ;si total open handles counter EMS_14_L1: CALL EMS_CHECK_HDL ;see if handle active CALL EMS_13 ;cnt number of pages for hdl JC EMS_14_S1 ;if bad handle, skip INC SI ;add to handle count MOV ES:[DI],DX ;write results to the array MOV ES:2[DI],BX EMS_14_S1: INC DX ;point to next handle ADD DI,4 ;incriment array pointer CMP DX,TOTAL_HANDLES ;have we check all handles? JL EMS_14_L1 ;no, loop back. MOV BX,SI ;Get number of active handles XOR AX,AX ;clear return code EMS_14_EXIT: POP DX RET EMS_14 ENDP ;====================================================================== ;Function 15. Get/Set Page Map ;====================================================================== EMS_15_TBL DW OFFSET EMS_15_0 ;Jump table for subfunctions DW OFFSET EMS_15_1 DW OFFSET EMS_15_2 DW OFFSET EMS_15_3 EMS_15 PROC NEAR ASSUME CS:CODE,DS:CODE,ES:NOTHING PUSH BX PUSH DX PUSH DS MOV DS,SS:[BP-8] ;Get original DS ASSUME DS:NOTHING CMP AL,3 ;check al for a number not 0-3 JA EMS_15_ERROR XOR AH,AH ;clear top byte of subfunction MOV BX,AX ;convert into jump address SAL BX,1 ADD BX,OFFSET EMS_15_TBL CALL CS:[BX] EMS_15_EXIT: POP DS POP DX POP BX RET EMS_15_ERROR: MOV AH,8FH ;invalid subfunction JMP SHORT EMS_15_EXIT EMS_15 ENDP ;---------------------------------------------------------------------- ;Function 15.0 Get mapping array ;---------------------------------------------------------------------- EMS_15_0 PROC NEAR ASSUME DS:NOTHING,ES:NOTHING PUSH SI PUSH DS PUSH CS POP DS ASSUME DS:CODE MOV SI,MAP_ARRAY_PTR ;ds:si points to page array MOV CX,9 ;es:di points to destination REP MOVSW ;copy mapping array XOR AH,AH POP DS POP SI RET EMS_15_0 ENDP ;---------------------------------------------------------------------- ;Function 15.1 Set mapping array ;---------------------------------------------------------------------- EMS_15_1 PROC NEAR ASSUME DS:NOTHING,ES:NOTHING PUSH SI XOR BX,BX ;start with logical page 0 ADD SI,2 ;move si past the handle pointer EMS_15_1_L1: MOV AX,DS:[SI] ;get current page address MOV DX,DS:2[SI] PUSH BX CALL EMS_EXCH_PAG ;Exchange current window page POP BX ;Point si to next address ADD SI,4 INC BX CMP BL,3 ;Have we done all 4 pages? JLE EMS_15_1_L1 ;No, loop back XOR AH,AH EMS_15_1_EXIT: POP SI RET EMS_15_1 ENDP ;---------------------------------------------------------------------- ;Function 15.2 Get & Set mapping array ;---------------------------------------------------------------------- EMS_15_2 PROC NEAR ASSUME DS:NOTHING,ES:NOTHING PUSH DI CALL EMS_15_0 ;Save current mapping array POP DI CALL EMS_15_1 ;Set new mapping context XOR AH,AH RET EMS_15_2 ENDP ;---------------------------------------------------------------------- ;Function 15.3 Get mapping array size ;---------------------------------------------------------------------- EMS_15_3 PROC NEAR ASSUME DS:NOTHING,ES:NOTHING MOV AX,0012H ;18 bytes in the page array RET EMS_15_3 ENDP ;====================================================================== ;Function 16. Get/Set Partial Page Map ;====================================================================== EMS_16_TBL DW OFFSET EMS_16_0 ;Jump table for subfunctions DW OFFSET EMS_16_1 DW OFFSET EMS_16_2 EMS_16 PROC NEAR ASSUME CS:CODE,DS:CODE,ES:NOTHING PUSH BX PUSH DX PUSH DS MOV DS,SS:[BP-8] ;Get original DS from stack ASSUME DS:NOTHING EMS_16_S1: XOR AH,AH ;clear top byte of subfunction CMP AL,2 ;check al for a number not 0-3 JA EMS_16_ERROR MOV DI,AX ;convert into jump address SAL DI,1 ADD DI,OFFSET EMS_16_TBL CALL CS:[DI] EMS_16_EXIT: POP DS POP DX POP BX RET EMS_16_ERROR: MOV AH,8FH ;invalid subfunction JMP SHORT EMS_16_EXIT EMS_16 ENDP ;---------------------------------------------------------------------- ;Function 16.0 Get mapping array ;---------------------------------------------------------------------- EMS_16_0 PROC NEAR ASSUME DS:NOTHING,ES:NOTHING MOV DI,SS:[BP-4] ;Get back original DI. MOV CX,DS:[SI] ;get count of mappable segs. MOV ES:[DI],CX ;save count EMS_16_0_L1: MOV AX,DS:2[SI] ;Get segment to convert CALL EMS_SEG2LOG ;convert segment onto page # JC EMS_16_0_EXIT MOV ES:2[DI],BX ;save physical page number SAL BX,1 ;Convert page number SAL BX,1 ; into offset ADD BX,CS:MAP_ARRAY_PTR MOV AX,CS:2[BX] MOV ES:4[DI],AX ;save address low MOV AX,CS:4[BX] MOV ES:6[DI],AX ;save address high ADD DI,6 INC SI ;point to next seg to save INC SI LOOP EMS_16_0_L1 XOR AX,AX EMS_16_0_EXIT: RET EMS_16_0 ENDP ;---------------------------------------------------------------------- ;Function 16.1 Set mapping array ;---------------------------------------------------------------------- EMS_16_1 PROC NEAR ASSUME DS:NOTHING,ES:NOTHING MOV CX,DS:[SI] ;get count of pages EMS_16_1_L1: MOV BX,2[SI] ;get logical page MOV AX,4[SI] ;get address of page to MOV DX,6[SI] ; restore CALL EMS_EXCH_PAG ;Exchange current window page ADD SI,6 ;Point si to next page LOOP EMS_16_1_L1 ;No, loop back XOR AX,AX ;Clear error code EMS_16_1_EXIT: RET EMS_16_1 ENDP ;---------------------------------------------------------------------- ;Function 16.2 Get partial mapping array size ;---------------------------------------------------------------------- EMS_16_2 PROC NEAR ASSUME DS:NOTHING,ES:NOTHING MOV AX,BX ;get nubmer of pages MOV AH,6 ;6 bytes per page MUL AH ADD AX,2 ;add room for count XOR AH,AH ;zero return code RET EMS_16_2 ENDP ;====================================================================== ;Function 17. Map Multiple Handle Pages ;====================================================================== EMS_17 PROC NEAR ASSUME CS:CODE,DS:CODE,ES:NOTHING MOV ES,SS:[BP-8] ;get pointer to map structure CALL EMS_17_INTERNAL RET EMS_17 ENDP ;---------------------------------------------------------------------- ;Function 17 (internal). Used by jump and call routines to map pages. ;---------------------------------------------------------------------- EMS_17_INTERNAL PROC NEAR ASSUME CS:CODE,DS:CODE,ES:NOTHING PUSH BX PUSH DX JC EMS_17_EXIT ;carry set, invalid handle CMP AL,1 ;no subfunction > 1. JA EMS_17_ERR1 CMP CX,4 ;Make sure count < number of JA EMS_17_ERR2 ; mappable pages. MOV CH,AL ;save subfunction EMS_17_L1: MOV AX,ES:2[SI] ;get physical page number/seg OR CH,CH JE EMS_17_S3 ;if seg address mapping, CALL EMS_SEG2LOG ; convert seg addr to number JC EMS_17_EXIT ;check for error on conversion MOV AL,BL EMS_17_S3: MOV BX,ES:[SI] ;get logical page number CLC ;handle valid PUSH CX ;save count CALL EMS_05 ;map page POP CX ;restore count OR AH,AH ;check for error JNE EMS_17_EXIT ADD SI,4 ;Move pointers to next DEC CL ; mapping structure. JNZ EMS_17_L1 XOR AX,AX ;clear return code EMS_17_EXIT: POP DX POP BX RET EMS_17_ERR1: MOV AH,8FH ;invalid subfunction JMP SHORT EMS_17_EXIT EMS_17_ERR2: MOV AH,8BH ;Number exceeds mappable pages JMP SHORT EMS_17_EXIT ; in the system EMS_17_INTERNAL ENDP ;====================================================================== ;Function 18. Reallocate Pages ;====================================================================== EMS_18 PROC NEAR ASSUME CS:CODE,DS:CODE,ES:NOTHING PUSH BX PUSH DX JC EMS_18_EXIT ;carry set, invalid handle MOV DI,BX ;save reallocation count PUSH BX CALL EMS_13 ;get current count MOV CX,BX POP BX ;get back new count SUB BX,CX JG EMS_18_INCREASE JL EMS_18_REDUCE XOR AH,AH ;clear return code EMS_18_EXIT: POP DX POP BX RET EMS_18_INCREASE: CALL EMS_ASSIGN JMP SHORT EMS_18_EXIT EMS_18_REDUCE: NEG BX ;turn into positive number CALL EMS_DEALLOC JMP SHORT EMS_18_EXIT EMS_18 ENDP ;====================================================================== ;Function 19. Get/Set Handle Attribute (Not Supported) ;====================================================================== EMS_19 PROC NEAR ASSUME CS:CODE,DS:CODE CMP AL,1 JE EMS_19_1 ;Set handle attribute. CMP AL,2 ;For subfunctions 0 and 2, JG EMS_19_ERR1 ; return volatile handle, EMS_19_GOOD_EXIT: XOR AX,AX ; non-volatile not supp EMS_19_EXIT: RET EMS_19_1: CALL EMS_CHECK_HDL ;See if good handle JC EMS_19_ERR2 CMP BL,1 ;See if legal attribute type JG EMS_19_ERR3 ; or if non-volatile. JL EMS_19_GOOD_EXIT MOV AH,91H ;function not supported JMP SHORT EMS_19_EXIT EMS_19_ERR1: MOV AH,8FH ;subfunction invalid JMP SHORT EMS_19_EXIT EMS_19_ERR2: MOV AH,83H ;invalid handle JMP SHORT EMS_19_EXIT EMS_19_ERR3: MOV AH,90H ;attribute type not defined. JMP SHORT EMS_19_EXIT EMS_19 ENDP ;====================================================================== ;Function 20. Get/Set Handle Name ;====================================================================== EMS_20 PROC NEAR ASSUME CS:CODE,DS:CODE,ES:NOTHING PUSH BX PUSH DX PUSH DS JC EMS_20_EXIT ;carry set, invalid handle PUSH AX ;find spot for handle MOV BX,CS ;get code segment MOV AX,DX ;Compute offset by multipling MOV AH,9 ; the handle number by the MUL AH ; size of each entry (9). MOV DX,AX ADD DX,HANDLE_ARRAY INC DX ;point dx past the handle used POP AX ; flag. OR AL,AL ;Check for get or set subfun. JNE EMS_20_S1 ;Get Handle Name MOV SI,DX ;load pointer to handle name JMP SHORT EMS_20_MOV ;Set Handle Name EMS_20_S1: CMP AL,1 ;Make sure that subfunction JNE EMS_20_ERR1 ; = 1. MOV DS,SS:[BP-8] ;Get original DS ASSUME DS:NOTHING PUSH SI PUSH DX CALL EMS_21_1 ;First, search for handle POP DX ; with this name. The POP SI ; return code must be a0h. AND AH,0FEH ; or a1h. CMP AH,0A0H JNE EMS_20_ERR2 MOV DI,DX ;Get back name pointer PUSH CS POP ES ASSUME ES:CODE EMS_20_MOV: MOV CX,8 ;copy name. move 8 bytes REP MOVSB XOR AX,AX ;clear return code EMS_20_EXIT: POP DS POP DX POP BX RET EMS_20_ERR1: MOV AH,8FH ;Invalid subfunction JMP SHORT EMS_20_EXIT EMS_20_ERR2: MOV AH,0A1H ;Handle already used JMP SHORT EMS_20_EXIT EMS_20 ENDP ;====================================================================== ;Function 21. Get Handle directory ;====================================================================== EMS_21_TBL DW OFFSET EMS_21_0 ;Jump table for subfunctions DW OFFSET EMS_21_1 DW OFFSET EMS_21_2 EMS_21 PROC NEAR ASSUME CS:CODE,DS:CODE,ES:NOTHING PUSH DS MOV DS,SS:[BP-8] ;Get original DS ASSUME DS:NOTHING CMP AL,2 ;check subfunction < 3 JA EMS_21_ERROR XOR AH,AH ;clear top byte of subfunction MOV DI,AX ;convert into jump address SAL DI,1 ADD DI,OFFSET EMS_21_TBL CALL CS:[DI] EMS_21_EXIT: POP DS RET EMS_21_ERROR: MOV AH,8FH ;invalid subfunction JMP SHORT EMS_21_EXIT EMS_21 ENDP ;---------------------------------------------------------------------- ;Function 21.0 Get Handle Directory ;---------------------------------------------------------------------- EMS_21_0 PROC NEAR ASSUME DS:NOTHING,ES:NOTHING PUSH DX PUSH CS POP DS ASSUME DS:CODE MOV SI,HANDLE_ARRAY MOV DI,SS:[BP-4] ;Get original DI XOR AX,AX ;Clear RC and hndl counter MOV DX,AX ;Start with handle 0 EMS_21_0_L1: CMP BYTE PTR [SI],0 ;Check flag to see if handle JE EMS_21_0_S1 ; is used. MOV ES:[DI],DX ;Store handle value INC SI ;move SI past handle flag ADD DI,2 ;move DI past handle MOV CX,8 ;8 char per handle name REP MOVSB INC AL ;add to handle count JMP SHORT EMS_21_0_S2 EMS_21_0_S1: ADD SI,9 ;move to the next handle EMS_21_0_S2: INC DX ;check next handle CMP DX,TOTAL_HANDLES ;last handle? JB EMS_21_0_L1 ;no, loop back POP DX RET EMS_21_0 ENDP ;---------------------------------------------------------------------- ;Function 21.1 Search for Named Handle ;---------------------------------------------------------------------- EMS_21_1 PROC NEAR ASSUME DS:NOTHING PUSH BX PUSH DS ;copy segment of name POP ES ASSUME ES:NOTHING MOV DI,SI MOV CX,8 ;Check for null string. If XOR AL,AL ; null, skip scan for dup REPE SCASB ; strings. JE EMS_21_1_ERR1 MOV CX,CS:TOTAL_HANDLES ;look at all handles PUSH CS ;ES:DI -> handle array POP ES ;DS:SI -> handle name ASSUME ES:CODE MOV BX,SI ;bx holds handle name ptr MOV AX,CS:HANDLE_ARRAY ;ax holds handle array ptr INC AX ;move ax past handle flag XOR DX,DX ;start handle count at 0 EMS_21_1_L1: MOV DI,AX ;Compare each of the handle MOV SI,BX ; names with the new handle PUSH CX MOV CX,8 REPE CMPSB POP CX JE EMS_21_1_EXIT ;If match found print err msg. ADD AX,9 ;move AX to next handle INC DX LOOP EMS_21_1_L1 MOV AH,0A0H ;handle not found JMP SHORT EMS_21_1_EXIT1 EMS_21_1_EXIT: XOR AH,AH EMS_21_1_EXIT1: POP BX RET EMS_21_1_ERR1: MOV AH,0A1H ;null handle found JMP SHORT EMS_21_1_EXIT1 EMS_21_1 ENDP ;---------------------------------------------------------------------- ;Function 21.2 Get Total Handles ;---------------------------------------------------------------------- EMS_21_2 PROC NEAR ASSUME DS:NOTHING MOV BX,CS:TOTAL_HANDLES ;Get number of allowed hdls XOR AX,AX ;Clear return code. RET EMS_21_2 ENDP ;====================================================================== ;Function 22. Alter Page Map and Jump ;====================================================================== EMS_22 PROC NEAR ASSUME CS:CODE,DS:CODE,ES:NOTHING JC EMS_22_EXIT ;carry set, invalid handle ;Map new pages into window MOV DI,SI ; ES:DI = pointer to map and MOV ES,SS:[BP-8] ; jump data MOV SI,ES:[DI] ;Modify return address on MOV SS:[BP+2],SI ; the stack to the address MOV SI,ES:2[DI] ; in the jump structure. MOV SS:[BP+4],SI MOV SI,ES:5[DI] ;Get pointer to mapping MOV ES,ES:7[DI] ; structure. MOV CL,ES:4[DI] ;get mapping count XOR CH,CH CALL EMS_17_INTERNAL ;alter page map EMS_22_EXIT: RET EMS_22 ENDP ;====================================================================== ;Function 23. Alter Page Map and Call ;====================================================================== EMS_23 PROC NEAR ASSUME CS:CODE,DS:CODE,ES:NOTHING JC EMS_23_JMP_END ;carry set, invalid handle CMP AL,2 ;Check for stack size function JNE EMS_23_S1 MOV BX,28 ;Say we need 28 bytes XOR AH,AH EMS_23_JMP_END: JMP EMS_23_EXIT EMS_23_S1: PUSH AX ;Save subfunction ;Map new pages into window MOV DI,SI ;get pointer to map and MOV ES,SS:[BP-8] ; jump data PUSH ES ;Save pointer to structure PUSH DI XOR CH,CH MOV CL,ES:[DI+4] ;get mapping count MOV SI,ES:[DI+5] ;get pointer to mapping MOV ES,ES:[DI+7] ; structure PUSH AX CLC ;indicate good handle CALL EMS_17_INTERNAL ;alter page map OR AH,AH POP AX ;Restore AX JNE EMS_23_EXIT ;Restore values in the registers and call. MOV AX,SS:[BP+6] ;get flags PUSH AX POPF ;load flags MOV ES,SS:[BP-10] ;restore ES MOV DS,SS:[BP-8] ;Restore DS MOV SI,SS:[BP-6] ;Restore SI MOV DI,SS:[BP-4] ;Restore DI MOV DI,SS:[BP-2] ;Restore CX ASSUME DS:NOTHING PUSH BP ;Save my base pointer MOV BP,SS:[BP] ;Restore BP MOV AX,0000 ;Clear return code CALL DWORD PTR DS:[SI] ;Call. POP AX ;Get back pointer to stack PUSH BP ;Save returned BP MOV BP,AX ;Restore my base pointer POP AX ;Get back returned BP PUSHF ;Save returned flags MOV [BP-10],ES MOV [BP-8],DS ;Put reg values on stack MOV [BP-6],SI ; to be restored on return MOV [BP-4],DI MOV [BP-2],CX POP CX ;Get back returned flags MOV SS:[BP+6],CX MOV SS:[BP],AX ;Save returned BP PUSH CS POP DS ASSUME DS:CODE ;Map old pages into window POP DI ;Get back pointer to structure POP ES XOR CH,CH MOV CL,ES:[DI+9] ;get mapping count MOV SI,ES:[DI+10] ;get pointer to mapping MOV ES,ES:[DI+12] ; structure CLC ;indicate good handle POP AX ;Restore subfunction CALL EMS_17_INTERNAL ;alter page map EMS_23_EXIT: RET EMS_23 ENDP ;====================================================================== ;Function 24. Move/Exchange Memory Region ;====================================================================== EMS_24_SUBFUN EQU [BP-1] ;Saved subfunction EMS_24_DIR EQU [BP-2] ;Direction flag for move EMS_24_COUNT EQU [BP-6] ;Amount of memory to move EMS_24_SRC_PTR EQU [BP-10] ;Source move pointer EMS_24_DEST_PTR EQU [BP-14] ;Destination move pointer EMS_24_RET_CODE EQU [BP-15] ;RC for non-fatal error codes EMS_24 PROC NEAR ASSUME CS:CODE,DS:CODE,ES:NOTHING PUSH BX ;Save registers PUSH DX MOV ES,SS:[BP-8] ;Get DS off original stack PUSH ES ;Push for local addressability PUSH SI PUSH BP MOV BP,SP ;Set up pointer to local data SUB SP,18 ;Make room on stack for data MOV EMS_24_SUBFUN,AL ;Save subfunction MOV BYTE PTR EMS_24_RET_CODE,0 MOV AX,ES:[SI] ;Get count from move struc MOV DX,ES:[SI+2] CMP DX,10H ;see if region size > 1M JB EMS_24_S0 MOV AH,96H ;region > 1M byte JMP EMS_24_EXIT EMS_24_S0: MOV WORD PTR [EMS_24_COUNT],AX ;Save count. Compute MOV WORD PTR [EMS_24_COUNT+2],DX ; the number of MOV CX,16384 ; 16K pages needed. DIV CX MOV CH,AL ;Save number of pages MOV CL,DL ;save remainder ;Verify handles have the pages assigned. (If Expanded memory.) ADD SI,4 ;move pointer to source descr MOV DI,-10 ;Pointer to src local store CALL EMS_CHECK_MOV JC EMS_24_JMP_EXIT PUSH AX ;Save source end address PUSH DX ADD SI,7 ;Point to destination block MOV DI,-14 ;Pointer to dest local store CALL EMS_CHECK_MOV POP DI ;Recover source end address POP BX JNC EMS_24_S01 ;If error flag set, exit EMS_24_JMP_EXIT: JMP EMS_24_EXIT EMS_24_S01: MOV BYTE PTR EMS_24_DIR,0 ;Set direction flag bottom up ;Check and adjust for overlap if necessary. If exchange, don't allow overlap. MOV CL,BYTE PTR ES:[SI] ;Get destination memory type ADD CL,BYTE PTR ES:[SI-7] ;Compare to source memory type CMP CL,1 ;0 = both conv, 1 = diff types, JE EMS_24_MOVEDATA ; 2 = both expanded. JB EMS_24_S2 ;0, check conv overlap. MOV CX,ES:[SI+1] ;Get dest handle CMP CX,ES:[SI-6] ;Compare to source handle JNE EMS_24_MOVEDATA ;Not the same, no overlap MOV CX,ES:[SI-2] ;Get source starting page CMP CX,ES:[SI+5] ;Compare dest starting page JB EMS_24_S1 ;If source starts first, JA EMS_24_S02 ; bottom up move. MOV CX,ES:[SI-4] ;Get source starting offset CMP CX,ES:[SI+3] ;Get source starting offset JB EMS_24_S1 ;Source lower, bottom up move EMS_24_S02: MOV BX,AX ;Copy from top down. MOV DI,DX ;Put end addr of Dest in DI,BX SUB SI,7 ;Point to source descriptor MOV BYTE PTR EMS_24_DIR,1 ;Set direction top down EMS_24_S1: CMP DI,ES:[SI+5] ;Compare end with start addr JB EMS_24_MOVEDATA ;No overlap JA EMS_24_OVERLAP ;Overlap CMP BX,ES:[SI+3] ;Same pages, check offsets JB EMS_24_MOVEDATA ;If less, no overlap JMP SHORT EMS_24_OVERLAP ;Check for overlap of conventional memory regions. EMS_24_S2: CMP DX,DI ;Compare high word JB EMS_24_S3 ;dest higher, top down JA EMS_24_S21 ;Less, bottom up. CMP AX,BX ;Compare low word of address JB EMS_24_S3 ;Jmp if dest addr higher EMS_24_S21: MOV SI,-14 ;Point to dest descriptor CALL EMS_24_ADR_CNV XCHG DI,DX ;Exchange starting addresses XCHG BX,AX MOV SI,-10 ;Point to source descriptor CALL EMS_24_ADR_CNV MOV BYTE PTR EMS_24_DIR,1 ;Set direction flag top down EMS_24_S3: SUB BX,WORD PTR [EMS_24_COUNT] ;Generate start addr SBB DI,WORD PTR [EMS_24_COUNT+2] CMP DX,DI ;Compare starting addr with JB EMS_24_MOVEDATA ; end of other block CMP AX,BX JBE EMS_24_MOVEDATA EMS_24_OVERLAP: MOV BYTE PTR EMS_24_RET_CODE,92H ;Indicate overlap CMP BYTE PTR EMS_24_SUBFUN,0 ;If exch. don't allow JE EMS_24_MOVEDATA ; overlap. MOV AH,97H ;Error, no overlap JMP EMS_24_EXIT ; on exchange. ;Move/Exchange the data EMS_24_MOVEDATA: MOV BX,MAP_ARRAY_PTR ;Save context of pages 0 & 1 PUSH [BX+8] ;Save address for page 1 PUSH [BX+6] PUSH [BX+4] ;Save address for page 0 PUSH [BX+2] STD CMP BYTE PTR EMS_24_DIR,0 ;If moving from top to bottom JNE EMS_24_MOVE0 ; set direction flag for move CLD MOV AX,ES:[SI-4] ;If move from bottom to top, MOV DX,ES:[SI-2] ; initialize the MOV WORD PTR [EMS_24_SRC_PTR],AX ; pointers back to MOV WORD PTR [EMS_24_SRC_PTR+2],DX ; the starting MOV AX,ES:[SI+3] ; addresses. MOV DX,ES:[SI+5] MOV WORD PTR [EMS_24_DEST_PTR],AX MOV WORD PTR [EMS_24_DEST_PTR+2],DX EMS_24_MOVE0: XOR CX,CX ;Clear last move count EMS_24_MOVELOOP: MOV ES,[BP+4] ;Restore move structure MOV BX,[BP+2] ; pointer to ES:BX MOV DX,ES ;Save ES MOV AX,CX ;Save last count ADD BX,4 ;Point to source descriptor XOR SI,SI ;Indicate source CALL EMS_24_MOV_SET PUSH ES ;Save source pointer PUSH DI XCHG CX,AX ;save count, restore last cnt MOV ES,DX ;Restore ES ADD BX,7 ;Point to dest mem descriptor MOV SI,1 CALL EMS_24_MOV_SET ;Map extended mem if needed POP SI ;Get back source pointer POP BX ;Save segment in BX CMP AX,CX ;Get lower count JA EMS_24_MOVE1 MOV CX,AX EMS_24_MOVE1: MOV AX,WORD PTR [EMS_24_COUNT] ;Get move count MOV DX,WORD PTR [EMS_24_COUNT+2] OR DX,DX ;See if at end of JNE EMS_24_MOVE2 ; count. If so, CMP AX,CX ; copy only to end JA EMS_24_MOVE2 ; of count. MOV CX,AX EMS_24_MOVE2: SUB AX,CX ;Subtract from count SBB DX,0 PUSH CX PUSH AX ;Save count PUSH DX CMP BYTE PTR EMS_24_SUBFUN,1 ;See if move or exch MOV DS,BX ;Time to set DS ASSUME DS:NOTHING JE EMS_24_EXCH REP MOVSB ;Move that data JMP SHORT EMS_24_MOVE3 EMS_24_EXCH: MOV BL,ES:[DI] ;Get dest byte MOVSB CMP BYTE PTR EMS_24_DIR,0 ;Check direction flag to JNE EMS_24_EXCH1 ; make sure of pointers MOV DS:[SI-1],BL ;Move dest byte to source JMP SHORT EMS_24_EXCH2 EMS_24_EXCH1: MOV DS:[SI+1],BL ;Move dest byte to source EMS_24_EXCH2: LOOP EMS_24_EXCH ;Loop until block exchanged. EMS_24_MOVE3: PUSH CS ;Restore DS altered by move POP DS ASSUME DS:CODE POP DX ;Get back count POP AX POP CX MOV WORD PTR [EMS_24_COUNT],AX ;Restore count MOV WORD PTR [EMS_24_COUNT+2],DX OR DX,DX JNE EMS_24_MOVE4 ;See if count has expired. OR AX,AX JLE EMS_24_LOOP_DONE EMS_24_MOVE4: JMP EMS_24_MOVELOOP EMS_24_LOOP_DONE: ;Restore pages 0 and 1. XOR BX,BX ;set physical page = 0 POP AX ;get address of page to POP DX ; restore CALL EMS_EXCH_PAG ;Exchange current window page MOV BX,1 ;set physical page = 1 POP AX ;get address of page to POP DX ; restore CALL EMS_EXCH_PAG ;Exchange current window page MOV AH,BYTE PTR EMS_24_RET_CODE ;Get return code EMS_24_EXIT: ADD SP,18 ;Deallocate local storage POP BP POP SI POP ES POP DX POP BX RET EMS_24 ENDP ;---------------------------------------------------------------------- ;Convert address to segment offset form ;Entry: dx ax - address ; si - pointer to local memory descriptor ;---------------------------------------------------------------------- EMS_24_ADR_CNV PROC NEAR PUSH AX PUSH DX MOV CX,16384 ;Convert address to seg:offset DIV CX MOV WORD PTR [BP+SI],DX ;Save offset MOV CL,10 SAL AX,CL MOV WORD PTR [BP+SI+2],AX ;Save segment POP DX POP AX RET EMS_24_ADR_CNV ENDP ;---------------------------------------------------------------------- ;Setup ems page for move. ;Entry: al - 0 = source page, 1 = destination page. ; es:bx - pointer to external memory descriptor ; cx - Count used on last move ;Exit: ES:DI - pointer to data to move ; cx - max count before crossing boundry. ;---------------------------------------------------------------------- EMS_24_MOV_SET PROC NEAR ASSUME DS:CODE PUSH AX PUSH BX PUSH DX MOV DX,SI MOV SI,-10 ;Use SI as offset to src_ptr OR DX,DX JE EMS_24_MOV_SET_S0 SUB SI,4 ;Point SI to dest_ptr EMS_24_MOV_SET_S0: MOV DH,BYTE PTR ES:[BX] ;Get memory type MOV AX,16383 ;Load constants for EMS mem MOV DI,1 OR DH,DH ;Check type of number JNE EMS_24_MOV_SET_S1 ;1 = EMS memory MOV DI,1024 ;Load constants for ; conventional memory. EMS_24_MOV_SET_S1: CMP BYTE PTR EMS_24_DIR,0 ;If bottom up move, skip JE EMS_24_MOV_SET_S3 ;Top down. SUB WORD PTR [BP+SI],CX ;Sub last move from offset JAE EMS_24_MOV_SET_S2 ;See if end of page MOV WORD PTR [BP+SI],AX ;Start at top of next page SUB WORD PTR [BP+SI+2],DI ;Point to next page EMS_24_MOV_SET_S2: MOV CX,WORD PTR [BP+SI] ;Get offset for count INC CX JMP EMS_24_MOV_SET_S5 ;Bottom up EMS_24_MOV_SET_S3: ADD WORD PTR [BP+SI],CX ;Add last move to offset CMP WORD PTR [BP+SI],AX ;See if end of page JBE EMS_24_MOV_SET_S4 EMS_24_MOV_SET_S31: MOV WORD PTR [BP+SI],0 ;Start at bottom of page ADD WORD PTR [BP+SI+2],DI ;Point to next page EMS_24_MOV_SET_S4: MOV CX,AX ;Compute count to end of page SUB CX,WORD PTR [BP+SI] INC CX EMS_24_MOV_SET_S5: OR DH,DH ;Check type of number JE EMS_24_MOV_SET_CONV1 ;If conventional, don't map PUSH CX ;Save new count PUSH DX MOV AL,DL ;Pass proper phyical page MOV DX,WORD PTR ES:[BX+1] ;Get handle MOV BX,WORD PTR [BP+SI+2] ;Put page in proper register PUSHF CLD ;Set assumed direction flag CLC ;Set handle good flag CALL EMS_05 ;Map page POPF POP DX POP CX ;Get count back MOV AX,WINDOW_SEG ;Get window segment OR DL,DL ;See if source or dest JE EMS_24_MOV_SET_S6 ;If destination, point to ADD AX,1024 ; 2nd page. 1024 paragraphs EMS_24_MOV_SET_S6: MOV ES,AX ;Set pointer to data EMS_24_MOV_SET_EXIT: MOV DI,WORD PTR [BP+SI] ;Load offset POP DX POP BX POP AX RET EMS_24_MOV_SET_CONV1: MOV DI,WORD PTR [BP+SI+2] MOV ES,DI JMP SHORT EMS_24_MOV_SET_EXIT EMS_24_MOV_SET ENDP ;---------------------------------------------------------------------- ;Check parameters for move or exchange ;Entry: es:si - pointer to memory descriptor ; bp+di - pointer to local store descriptor ; ch - number of extended pages needed ; cl - number of bytes into last extended page ;Exit: dx,ax - ending address if conventional ; ax - ending page if expanded ; dx - ending offset if expanded ;---------------------------------------------------------------------- EMS_CHECK_MOV PROC NEAR ASSUME DS:CODE,ES:NOTHING PUSH BX PUSH CX PUSH DI XOR AX,AX MOV AL,CH ;Get number of pages needed MOV DI,AX ;Save number of pages in DI XOR CH,CH MOV AX,ES:[SI+5] ;Get segment/page MOV BX,ES:[SI+3] ;get offset MOV DL,ES:[SI] ;Get memory type OR DL,DL ;See if EMS or low memory JE EMS_CHECK_MOV_CONV ;jump if low memory CMP DL,1 ;If not low mem make sure JE EMS_CHECK_MOV_S1 ; EMS memory. MOV AH,98H ;Invalid memory type JMP EMS_CHECK_MOV_SET_ERR EMS_CHECK_MOV_S1: CMP BX,3FFFH ;Check for offset < 16K JA EMS_CHECK_MOV_ERR1 ;See if the handle owns enough pages to hold the region. MOV DX,ES:[SI+1] ;Get handle PUSH CX CALL EMS_CHECK_HDL ;Verify handle. CALL EMS_13 ;Get number of pages owned POP CX ; by handle OR AH,AH ;If error, set carry and JNE EMS_CHECK_MOV_SET_ERR ; return. MOV DX,BX ;save number of pages MOV BX,ES:[SI+5] ;Get logical page number MOV AX,DI ;Copy number of pages needed ADD AX,BX ;Add starting page. ADD CX,ES:[SI+3] ;Add start offset to remainder DEC CX ; of the num of pages needed. CMP CX,16384 JL EMS_CHECK_MOV_S4 ;If rem+offset > 16K add a INC AX ; page to the num needed. SUB CX,16384 EMS_CHECK_MOV_S4: CMP AX,DX ;Compare to total number of JG EMS_CHECK_MOV_ERR3 ; pages. MOV DX,CX ;Copy ending offset XCHG AX,DX ;Exchange offset and segment EMS_CHECK_MOV_EXIT: CLC ;Clear error flag EMS_CHECK_MOV_EXIT1: POP DI ;Restore registers MOV [BP+DI],AX ;Save offset MOV [BP+DI+2],DX ;Save segnent/page POP CX POP BX RET EMS_CHECK_MOV_CONV: MOV CX,16 ;convert segment into address MUL CX ADD AX,BX ;Add offset ADC DX,0 ADD AX,WORD PTR [EMS_24_COUNT] ;Add len to start addr ADC DX,WORD PTR [EMS_24_COUNT+2] SUB AX,1 ;Decriment count SBB DX,0 JMP SHORT EMS_CHECK_MOV_EXIT EMS_CHECK_MOV_ERR1: MOV AH,95H ;offset too large EMS_CHECK_MOV_SET_ERR: STC ;Indicate error JMP SHORT EMS_CHECK_MOV_EXIT1 EMS_CHECK_MOV_ERR3: MOV AH,93H ;Not enough pages JMP SHORT EMS_CHECK_MOV_SET_ERR EMS_CHECK_MOV ENDP ;====================================================================== ;Function 25. Get Mappable Physical Address Array ;====================================================================== EMS_25 PROC NEAR ASSUME CS:CODE,DS:CODE,ES:NOTHING OR AL,AL ;check subfunction JE EMS_25_S1 CMP AL,1 ;assure subfunction 0 or 1. JNE EMS_25_ERR1 MOV WORD PTR SS:[BP-2],4 ;replace saved cx with 4 JMP SHORT EMS_25_EXIT EMS_25_S1: MOV AX,WINDOW_SEG XOR CX,CX EMS_25_L1: MOV ES:[DI],AX ;write segment MOV ES:2[DI],CX ;write segment number ADD AX,1024 ;Point to next segment ADD DI,4 INC CX ;Indicate next page CMP CX,3 JLE EMS_25_L1 INC CX ;number is 1 based not 0 based EMS_25_EXIT: XOR AX,AX ;clear return code EMS_25_EXIT1: RET EMS_25_ERR1: MOV AH,8FH ;Unknown subfunction JMP SHORT EMS_25_EXIT1 EMS_25 ENDP ;====================================================================== ;Function 26. Get Expanded Memory Hardware Information ;====================================================================== EMS_26 PROC NEAR ASSUME CS:CODE,DS:CODE,ES:NOTHING CMP OS_ENABLED,1 ;Are OS funcctions enabled? JNE EMS_26_ERR1 ;No, exit CMP AL,1 ;Subfunction 1, get page cnt JB EMS_26_0 ;Jmp to subfunction 0 JA EMS_26_ERR2 ;If > 1, invalid subfunction. EMS_26_1: CALL EMS_03 ;Since raw page = normal page, JMP SHORT EMS_26_EXIT ; get normal page count. EMS_26_0: XOR CX,CX MOV WORD PTR ES:[DI],1024 ;16K pages (1024 paragraphs) MOV ES:2[DI],CX ;No alternate register sets CALL EMS_15_3 ;Get context area size MOV ES:4[DI],AX MOV ES:6[DI],CX ;No DMA channels MOV ES:8[DI],CX ;DMA channel operation XOR AX,AX ;clear return code EMS_26_EXIT: RET EMS_26_ERR1: MOV AH,0A4H ;operating system denied JMP SHORT EMS_26_EXIT ; access. EMS_26_ERR2: MOV AH,8FH ;Invalid subfunction JMP SHORT EMS_26_EXIT EMS_26 ENDP ;====================================================================== ;Function 27. Get handle and allocate pages ;====================================================================== EMS_27 PROC NEAR ASSUME DS:CODE,ES:NOTHING PUSH BX ;Save register CMP BX,TOTAL_PAGES ;Make sure request is not out JLE EMS_27_S1 ; of range. MOV AH,87H ;Not enough pages in system JMP SHORT EMS_27_EXIT EMS_27_S1: PUSH BX ;save num. of pages to alloc XOR DX,DX ;search for handle =-1 (unaloc) DEC DX CLC CALL EMS_13 ;get unallocated page count. POP CX CMP BX,CX ;check for enough free pages JL EMS_27_ERR1 MOV DI,HANDLE_ARRAY ;Assign handle XOR AX,AX ;search for free handles MOV DX,AX ;dx=0 at start of hndl search EMS_27_L1: CMP AL,[DI] ;if handle id = 0 then that JE EMS_27_S2 ; hndl has not been allocated. ADD DI,9 ;Move di to point to next id. INC DX CMP DX,TOTAL_HANDLES ;have we searched all handles? JB EMS_27_L1 MOV AH,85H ;no free handles JMP SHORT EMS_27_EXIT EMS_27_S2: DEC BYTE PTR [DI] ;indicate that handle is used MOV BX,CX CALL EMS_ASSIGN ;alloc pages, dx = new handle EMS_27_EXIT: POP BX ;Restore register RET EMS_27_ERR1: MOV AH,88H JMP SHORT EMS_27_EXIT EMS_27 ENDP ;====================================================================== ;Function 28. Alternate Map Register Set ;====================================================================== EMS_28_TBL DW OFFSET EMS_28_0 ;Jump table for subfunctions DW OFFSET EMS_28_1 DW OFFSET EMS_28_2 DW OFFSET EMS_28_3 DW OFFSET EMS_28_4 DW OFFSET EMS_28_3 DW OFFSET EMS_28_6 EMS_28 PROC NEAR ASSUME CS:CODE,DS:CODE,ES:NOTHING CMP OS_ENABLED,1 ;See if function enabled JNE EMS_28_ERR1 CMP AL,8 ;check al for a number not 0-8 JA EMS_28_ERR2 CMP AL,6 ;check al for function 4-8. JLE EMS_28_S1 ;If >5 point to unsupported MOV AL,6 ; routine. EMS_28_S1: XOR AH,AH ;clear top byte of subfunction MOV DI,AX ;convert into jump address SAL DI,1 ADD DI,OFFSET EMS_28_TBL XOR AX,AX ;clear return code before call CALL CS:[DI] EMS_28_EXIT: RET EMS_28_ERR1: MOV AH,0A4H ;operating system denied JMP SHORT EMS_28_EXIT ; access. EMS_28_ERR2: MOV AH,8FH ;invalid subfunction JMP SHORT EMS_28_EXIT EMS_28 ENDP ;---------------------------------------------------------------------- ;Function 28.0 Get Alternate Map Register Set ;---------------------------------------------------------------------- EMS_28_0 PROC NEAR PUSH DX MOV ES,ALT_MAP_PTRS ;Get pointer MOV DI,ALT_MAP_PTRO MOV SS:[BP-4],DI ;save values for exit MOV SS:[BP-10],ES OR DI,DI ;See if it is zero JNE EMS_28_0_S1 MOV CX,ES ;If so, exit without saving OR CX,CX ; page map array. XOR AX,AX ;Clear return code JE EMS_28_0_EXIT EMS_28_0_S1: PUSH DI ;save original pointer CALL EMS_15_0 ;copy page map POP DI ;The return code will be EMS_28_0_EXIT: XOR BL,BL ; set by Function 15.0 POP DX ;Indicate non-support for RET ; alternate mapping regs. EMS_28_0 ENDP ;---------------------------------------------------------------------- ;Function 28.1 Set Alternate Map Register Set ;---------------------------------------------------------------------- EMS_28_1 PROC NEAR PUSH BX PUSH DX OR BL,BL ;check bl = 0 JNE EMS_28_1_ERR MOV DI,[BP-4] ;Restore DI MOV ALT_MAP_PTRS,ES ;Save mapping pointer MOV ALT_MAP_PTRO,DI OR DI,DI ;See if it is zero JNE EMS_28_1_S1 MOV CX,ES ;If so, exit without restoring OR CX,CX ; page map array. JE EMS_28_1_EXIT EMS_28_1_S1: PUSH DS MOV SI,ES ;Put pointer into ds:si for MOV DS,SI ; function 15.1 call. ASSUME DS:NOTHING MOV SI,DI ;DS:SI = ES:DI CALL EMS_15_1 ;Restore page map POP DS ASSUME DS:CODE EMS_28_1_EXIT: POP DX POP BX RET EMS_28_1_ERR: MOV AH,9CH ;Alternate map register JMP SHORT EMS_28_EXIT ; sets not supported. EMS_28_1 ENDP ;---------------------------------------------------------------------- ;Function 28.2 Get Alternate Map Save Array Size ;---------------------------------------------------------------------- EMS_28_2 PROC NEAR CALL EMS_15_3 ;Get save array size. MOV DX,AX RET EMS_28_2 ENDP ;---------------------------------------------------------------------- ;Function 28.3 and 28.5 Deallocate Map Register Set ;---------------------------------------------------------------------- EMS_28_3 PROC NEAR XOR BL,BL ;set bl = 0 XOR AX,AX RET EMS_28_3 ENDP ;---------------------------------------------------------------------- ;Function 28.4 Deallocate Alternate Map Register Set ;---------------------------------------------------------------------- EMS_28_4 PROC NEAR OR BL,BL ;See if zero page indicated JNE EMS_28_4_ERR1 ; if not, error XOR AX,AX ;Clear return code. MOV ALT_MAP_PTRS,AX ;Clear mapping pointer MOV ALT_MAP_PTRO,AX EMS_28_4_EXIT: RET EMS_28_4_ERR1: MOV AH,9CH ;Alt register sets not JMP SHORT EMS_28_4_EXIT ; supported EMS_28_4 ENDP ;---------------------------------------------------------------------- ;Function 28.6-28.8 Unsupported Subfunctions ;---------------------------------------------------------------------- EMS_28_6 PROC NEAR OR BL,BL ;see if zero page indicated JNE EMS_28_6_ERR1 ;if not, error XOR AX,AX ;clear return code. EMS_28_6_EXIT: RET EMS_28_6_ERR1: MOV AH,9CH ;Alt register sets not JMP SHORT EMS_28_6_EXIT ; supported EMS_28_6 ENDP ;====================================================================== ;Function 30. OS/E Functions ;====================================================================== EMS_30 PROC NEAR PUSH DX CMP OS_PASS_LOW,0 JNE EMS_30_S1 CMP OS_PASS_HIGH,0 JE EMS_30_S2 ;first call, create password. EMS_30_S1: CMP OS_PASS_LOW,BX ;Check password JNE EMS_30_ERR1 CMP OS_PASS_HIGH,CX JNE EMS_30_ERR1 JMP SHORT EMS_30_S3 EMS_30_S2: PUSH AX ;Read the system time using XOR AH,AH ; bios int 1A function 00. INT 1AH MOV AX,DX ;copy low word of time INC CX ;multiply by high word. Inc MUL CX ;to assure count <> 0. MOV OS_PASS_LOW,AX MOV OS_PASS_HIGH,DX MOV BX,AX ;Return password in BX,CX MOV SS:[BP-2],DX ;Update CX on stack POP AX ;get back subfunction EMS_30_S3: CMP AL,2 ;return key function JNE EMS_30_S4 XOR AX,AX ;Clear return code MOV OS_PASS_LOW,AX ;Clear password MOV OS_PASS_HIGH,AX MOV OS_ENABLED,1 ;set op system flag JMP SHORT EMS_30_EXIT EMS_30_S4: CMP AL,1 ;Disable op system functions JNE EMS_30_S5 MOV OS_ENABLED,0 ;Clear flag JMP SHORT EMS_30_EXIT EMS_30_S5: OR AL,AL ;Enable op system functions JNE EMS_30_ERR2 MOV OS_ENABLED,1 ;Set flag EMS_30_EXIT: XOR AX,AX EMS_30_EXIT1: POP DX RET EMS_30_ERR1: MOV AH,0A4H ;Access denied JMP SHORT EMS_30_EXIT1 EMS_30_ERR2: MOV AH,8FH ;Subfunction not defined JMP SHORT EMS_30_EXIT1 EMS_30 ENDP ;====================================================================== ;Unsupported Function ;====================================================================== EMS_UNSP PROC NEAR ASSUME CS:CODE,DS:CODE,ES:NOTHING MOV AH,91H ;Feature not supported. RET EMS_UNSP ENDP ;----------------------------------------------------------------------------- ;Convert segment address into logical page number ;Entry: ax - segment address to convert EXIT: bl - logical page number ;----------------------------------------------------------------------------- EMS_SEG2LOG PROC NEAR ASSUME CS:CODE,DS:NOTHING,ES:NOTHING PUSH CX PUSH DX XOR BX,BX ;clear logical sector number MOV DX,CS:WINDOW_SEG MOV CX,4 EMS_SEG2_L1: CMP AX,DX JE EMS_SEG2_FND ADD DX,400H INC BX LOOP EMS_SEG2_L1 MOV AH,8BH ;segment not valid STC JMP SHORT EMS_SEG2_EXIT EMS_SEG2_FND: CLC EMS_SEG2_EXIT: POP DX POP CX RET EMS_SEG2LOG ENDP ;------------------------------------------------------------------------ ;EMS convert logical page to address ;Entry: bx = logical page dx = handle of page owner ;Exit: dx,ax - absolute address of page. carry set - page not found ;------------------------------------------------------------------------ EMS_LOG2PHY PROC NEAR ASSUME CS:CODE,DS:CODE,ES:NOTHING PUSH DI MOV DI,PAG_OWNER_TBL ;Point to page owner table MOV CX,TOTAL_PAGES ;Check entry for each page EMS_LOG2P_L1: CMP BYTE PTR [DI],DL ;See if owned by handle JNE EMS_LOG2P_S1 CMP WORD PTR [DI+1],BX ;See if this is the page JE EMS_LOG2P_S2 ; we have been looking for. EMS_LOG2P_S1: ADD DI,3 LOOP SHORT EMS_LOG2P_L1 MOV AH,8AH ;page out of range for handle STC JMP SHORT EMS_LOG2PHY_EXIT EMS_LOG2P_S2: SUB DI,PAG_OWNER_TBL ;compute the phy page address MOV AX,DI XOR DX,DX ;Clear high word MOV CX,3 ;Divide by size of each entry DIV CX MOV CX,16384 ;Mul page number by size of MUL CX ; page. ADD AX,EXTEND_ADRL ;Add starting address ADC DL,EXTEND_ADRH XOR DH,DH CLC ;clear error flag EMS_LOG2PHY_EXIT: POP DI RET EMS_LOG2PHY ENDP ;------------------------------------------------------------------------ ;EMS Assign pages bx = number of pages needed dx = handle to assign pages. ;------------------------------------------------------------------------ EMS_ASSIGN PROC NEAR ASSUME CS:CODE,DS:CODE,ES:NOTHING CMP AX,TOTAL_PAGES ;see if enough total pages JG EMS_ASSIGN_ERR2 PUSH DX ;save handle PUSH BX ;save pages to add MOV DX,0FFFFH ;load unassigned handle CLC ;Get number of unassigned CALL EMS_13 ; pages. POP AX ;Get back number of pages POP DX ;Get back handle CMP BX,AX ;are there enough pages? JL EMS_ASSIGN_ERR1 ;No, return error code. PUSH AX ;Save number of pages to alloc CLC ;Set handle found flag CALL EMS_13 ;Get number of pages assigned POP AX ;Get back num pages requested MOV DI,PAG_OWNER_TBL ;point to page owner table MOV CX,TOTAL_PAGES ;Get size of the array INC CX ;Make sure loop complete EMS_ASSIGN_L1: OR AX,AX ;See if we have assigned JE EMS_ASSIGN_S2 ; enough pages. CMP BYTE PTR [DI],0FFH ;see if page is unowned JNE EMS_ASSIGN_S1 ;Page owned, try another. MOV [DI],DL ;if so, assign it to the hndl MOV [DI+1],BX ;Assign page number INC BX ;inc page number to assign DEC AX ;one less page needed. EMS_ASSIGN_S1: ADD DI,3 ;point to the next page entry LOOP EMS_ASSIGN_L1 EMS_ASSIGN_ERR1: MOV AH,88H ;not enough unallocated pages STC ;set error flag JMP SHORT EMS_ASSIGN_EXIT EMS_ASSIGN_ERR2: MOV AH,87H ;not enough pages in system STC ;set error flag JMP SHORT EMS_ASSIGN_EXIT EMS_ASSIGN_S2: CLC XOR AX,AX ;Clear return code. EMS_ASSIGN_EXIT: RET EMS_ASSIGN ENDP ;------------------------------------------------------------------------ ;EMS Deallocate pages ;Entry: dx = handle ; bl = number of pages to deallocate ;------------------------------------------------------------------------ EMS_DEALLOC PROC NEAR ASSUME CS:CODE,DS:CODE,ES:NOTHING CMP BL,0FFH ;See if clear all JNE EMS_DEALLOC_S0 XOR BX,BX JMP SHORT EMS_DEALLOC_S1 EMS_DEALLOC_S0: XOR BH,BH PUSH BX ;Save num of pages to dealloc CLC CALL EMS_13 ;Get num of pages owned POP AX ;Get back num pages to dealloc SUB BX,AX ;Sub dealloc from total EMS_DEALLOC_S1: MOV DI,PAG_OWNER_TBL ;Point to the page owner table MOV CX,TOTAL_PAGES EMS_DEALLOC_L1: CMP [DI],DL ;compare handle JNE EMS_DEALLOC_S2 ;if not, keep looking CMP [DI+1],BX ;compare page number if above JB EMS_DEALLOC_S2 ; new limit, erase. Else, MOV BYTE PTR [DI],0FFH ; keep looking MOV WORD PTR [DI+1],0FFFFH EMS_DEALLOC_S2: ADD DI,3 ;Point to next entry LOOP EMS_DEALLOC_L1 EMS_DEALLOC_EXIT: XOR AH,AH ;Clear return code. RET EMS_DEALLOC ENDP ;----------------------------------------------------------------------------- ;EMS Check Handle ;Entry: dx = handle to check Exit: zero flag set - handle not found, ah = 83h ;----------------------------------------------------------------------------- EMS_CHECK_HDL PROC NEAR ASSUME CS:CODE,DS:CODE,ES:NOTHING PUSH DX PUSH BX OR DH,DH ;dh must be 0 for valid handle JNE EMS_CHECK_ERROR XCHG AX,DX ;Save ax MOV AH,9 ;Convert handle into an index MUL AH ; into the array MOV BX,AX ;copy to base register ADD BX,HANDLE_ARRAY ;add base address of array MOV AX,DX ;restore ax CMP BYTE PTR [BX],0 ;If byte<>0, then good handle JE EMS_CHECK_ERROR CLC ;clear error flag EMS_CHECK_EXIT: POP BX POP DX RET EMS_CHECK_ERROR: MOV AH,83H ;load error return code in ah STC ;set error flag JMP SHORT EMS_CHECK_EXIT EMS_CHECK_HDL ENDP ;------------------------------------------------------------------------ ;EMS exchange page ;Entry: bl = window page to map dl,ax = absolute address of page to map. ;------------------------------------------------------------------------ EMS_EXCH_PAG PROC NEAR ASSUME CS:CODE,DS:NOTHING,ES:NOTHING PUSH CX PUSH SI PUSH DS PUSH ES PUSH CS ;point DS, ES to code segment POP DS PUSH CS POP ES ASSUME DS:CODE,ES:CODE PUSH DEST.BASE_ADRL ;Save GTD data in case a PUSH SOURCE.BASE_ADRL ; reentrant call is made. MOV BH,DEST.BASE_ADRH PUSH BX MOV BH,SOURCE.BASE_ADRH PUSH BX PUSH AX ;Save page address PUSH DX XOR BH,BH ;Convert physical page number SAL BX,1 ; into an index, SAL BX,1 MOV DI,OFFSET WINDOW_ADDR_BASE ;Point to window addr MOV SI,MAP_ARRAY_PTR ;Point to mapping array. INC SI INC SI ;Check to see if the address requested has already been mapped. PUSH BX ;Save offset into table MOV DH,0FFH ;Init local page flag. XOR BX,BX ;Search the mapping table MOV CX,4 ; for the address to be EMS_EXCH_L1: CMP AX,[SI+BX] ; mapped. If found, use JNE EMS_EXCH_S1 ; the data from the mapped CMP DL,[SI+BX+2] ; page since it may be more JE EMS_EXCH_LOCAL ; accurate than the page EMS_EXCH_S1: ADD BX,4 ; in extended memory. LOOP EMS_EXCH_L1 JMP SHORT EMS_EXCH_S2 ;Local page not found EMS_EXCH_LOCAL: MOV AX,[SI+BX] ;Replace new page address with MOV DL,[SI+BX+2] ; local page address. MOV DH,BL ;Save local page index. EMS_EXCH_S2: POP BX ;Get original page index CMP BL,DH ;See if we are remapping page JNE EMS_EXCH_S3 ;If different, continue ADD SP,4 ;Clean up stack JMP SHORT EMS_EXCH_EXIT ;If same page, skip everything ;Save page currently mapped. EMS_EXCH_S3: PUSH AX ;Save new page address PUSH DX MOV AX,[SI+BX] ;Load address of current page MOV DL,[SI+BX+2] ; into destination registers. OR AX,AX ;If the current page is JNE STORE_PAGE ; unowned, don't save it. OR DL,DL JE LOAD_PAGE STORE_PAGE: MOV CX,[DI+BX] ;Load physical page address MOV DH,[DI+BX+2] ; into source registers. CALL EMS_MOVE_DATA ;Load in page from extended memory. LOAD_PAGE: POP DX ;Pop new page address into POP CX ; source registers. MOV DH,DL CLI ;Critical code, no interrupts POP AX ;Get back original destination MOV [SI+BX+2],AL ; address. POP AX ;Load address of new page into MOV [SI+BX],AX ; page map array. OR CX,CX ;If the current page is JNE EMS_EXCH_S4 ; unowned, don't save it. OR DH,DH JE EMS_EXCH_EXIT EMS_EXCH_S4: MOV AX,[DI+BX] ;Get window address again. MOV DL,[DI+BX+2] CALL EMS_MOVE_DATA ;Move memory EMS_EXCH_EXIT: STI ;All clear, allow interrupts POP BX ;Restore GDT data MOV SOURCE.BASE_ADRH,BH POP BX MOV DEST.BASE_ADRH,BH POP SOURCE.BASE_ADRL POP DEST.BASE_ADRL POP ES ;Restore registers POP DS POP SI POP CX RET EMS_EXCH_PAG ENDP ;----------------------------------------------------------------------------- ;EMS MOVE DATA moves blocks of data using BIOS move block function. ; Entry: DL,AX - destination address CX,DH - source address. ;----------------------------------------------------------------------------- EMS_MOVE_DATA PROC NEAR PUSH SI MOV SI,OFFSET GDT ;ES:SI point to GDT MOV DEST.BASE_ADRL,AX ;store source address MOV DEST.BASE_ADRH,DL MOV SOURCE.BASE_ADRL,CX ;store destination address MOV SOURCE.BASE_ADRH,DH MOV AH,87H ;BIOS move extended block MOV CX,2000H ;move 8192 words INT 15H ;call BIOS POP SI RET EMS_MOVE_DATA ENDP ;----------------------------------------------------------------------------- ;Init1. code initializes memory below this address then returns. ;----------------------------------------------------------------------------- INITIALIZE1 PROC NEAR INIT1: ASSUME CS:CODE,DS:CODE,ES:CODE MOV DI,PAG_OWNER_TBL MOV AX,TOTAL_PAGES ;Compute size of page owner MOV DX,3 ; table. MUL DX MOV CX,AX XOR AX,AX ;load ff's into page owner tbl DEC AX ; because ff is invalid hndl. REP STOSB MOV AX,TOTAL_HANDLES ;Compute size of handle array MOV AH,9 ;9 bytes / handle MUL AH MOV CX,AX ADD CX,36 ;Add room for context save XOR AX,AX ; area. REP STOSW MOV DI,HANDLE_ARRAY ;activate system handle DEC BYTE PTR [DI] RET INITIALIZE1 ENDP ;====================== End of resident Code ============================= DATA_START = $ VDISK_HEADER DB 'VDISK V' ERRMSG DB 'Not enough memory',13,10,'$' ;=========================================================================== ;Initialize. This routine sets up the EMS driver. ;=========================================================================== INITIALIZE PROC NEAR ASSUME CS:CODE,DS:CODE,ES:NOTHING PUSH CS ;Parse command line POP ES LDS SI,[REQ_HEADADR] ;get back addr of hdr ASSUME DS:NOTHING,ES:CODE LDS SI,DS:[SI.CONFIG_PTR] ;Get pointer to config line MOV BH,1 ;Look for first non-character MOV CX,80 ;80 characters in line CALL SCAN_FOR ;Scan for non-character. OR AH,AH ;see if found JNE CHK_FOR_VDISK ;not found, skip remainder XOR BH,BH ;Look for next character CALL SCAN_FOR ;Scan for character OR AH,AH ;see if found JNE CHK_FOR_VDISK ;not found, skip remainder ;----------------------------------------------------------------------------- ;Non-blank line after driver name. Attempt to convert to memory size in Kbytes ;----------------------------------------------------------------------------- DEC SI ;backup to 1st number MOV CX,5 ;Max 5 numbers. XOR AX,AX ;Clear running total MOV DI,10 ;Decimal conversion constant INIT_LOOP1: MOV BL,DS:[SI] ;Get number INC SI ;Point to next number. SUB BL,'0' ;Convert to number and see JB INIT_SKIP1 ; if in range for a number. CMP BL,9 JA INIT_SKIP1 XOR BH,BH MUL DI ;Mul by 16 to convert to hex ADD AX,BX ;add to current total LOOP INIT_LOOP1 ;----------------------------------------------------------------------------- ;Compute number of pages available for allocated memory. ;----------------------------------------------------------------------------- INIT_SKIP1: XOR DX,DX ;Clear high word for divide MOV DI,16 ;Divide number of Kbytes DIV DI ; by 16 Kbytes / page. OR AX,AX ;if number less than 1 page JE CHK_FOR_VDISK ; use default 24 pages. MOV CS:TOTAL_PAGES,AX ;Save number of pages. ;----------------------------------------------------------------------------- ;Check for vdisk driver by reading int 19 vector. ;----------------------------------------------------------------------------- CHK_FOR_VDISK: PUSH CS ;Set DS = CS POP DS ASSUME DS:CODE MOV AX,3519H ;Get interrupt vector 19 INT 21H ;ES points to VDISK segment MOV DI,12H ;VDISK header at offset 12h MOV SI,OFFSET VDISK_HEADER MOV CX,8 ;8 characters in header XOR BX,BX ;assume no memory used by vdisk REPE CMPSB ;Compare header JNE CHK_EXT_MEM ;----------------------------------------------------------------------------- ;If VDISK present, read top of available memory from inside VDISK driver. ;----------------------------------------------------------------------------- MOV SI,2CH ;load offset of memory used MOV AX,ES:[SI] ;Get amount of memory used by MOV DL,ES:[SI+2] ; vdisk SUB DL,10H ;Subtract 1 Mbyte starting adr XOR DH,DH MOV BX,16384 ;Convert to 16k pages DIV BX MOV BX,AX ;save result in BX ;----------------------------------------------------------------------------- ;Find upper limit of extended memory. ;----------------------------------------------------------------------------- CHK_EXT_MEM: PUSH CS ;ES = CS POP ES ASSUME ES:CODE MOV AH,88H ;Get extended memory function CLC ;clr err flag. (fix IBMCACHE) INT 15H ;Returns extended memory in JC EXTEND_ERROR ; 1k pages. MOV CL,4 ;Convert number of 1k pages SAR AX,CL ; into number of 16k pages. SUB AX,TOTAL_PAGES ;See if there is enough room. JL EXTEND_ERROR CMP AX,BX ;Subtract memory used by vdisk JGE EXTEND_MEM_OK1 EXTEND_ERROR: JMP DISP_ERR ;Error, abort instalation. ;----------------------------------------------------------------------------- ;Compute the starting address of the extended memory area for int 15. ;----------------------------------------------------------------------------- EXTEND_MEM_OK1: PUSH CS ; ES = CS POP ES ;Convert memory req. to 1k ASSUME ES:CODE ; pages then store this MOV CL,4 ; value for use as the new SAL AX,CL ; extended memory limit. MOV EXT_MEM_LIMIT,AX MOV CX,1024 ;Convert number of 1024 MUL CX ; byte pages to absolute adr ADD DL,10H ;Add starting address of MOV EXTEND_ADRL,AX ; extended memory and MOV EXTEND_ADRH,DL ; save. ;----------------------------------------------------------------------------- ;Initialize the variables and pointers needed to emulate the EMS spec. ;----------------------------------------------------------------------------- MOV BX,OFFSET DATA_START ;Get end of installed code. MOV PAG_OWNER_TBL,BX ;Save pointer to page table MOV AX,TOTAL_PAGES ;Get number of pages MOV DX,3 MUL DX ADD AX,BX ;Add to current pointer MOV HANDLE_ARRAY,AX ;Save pointer to handle array MOV CX,AX ;save current position MOV AX,TOTAL_HANDLES ;compute size of handle MOV AH,9 ; array using 9 bytes / hdl. MUL AH ADD AX,CX MOV MAP_ARRAY_PTR,AX ;map array 18 bytes. 4 arrays. ADD AX,72+15 ;Arrays + 15 to next segment. ;----------------------------------------------------------------------------- ;Compute the memory requirments for driver. ;----------------------------------------------------------------------------- MOV CL,4 ;Convert offset into a SHR AX,CL ; segment value MOV BX,CS ;Get code segment ADD AX,BX ;Add code segment to code length MOV WINDOW_SEG,AX ;Store starting segment of ems PUSH AX ;----------------------------------------------------------------------------- ;Generate and store abolute addresses of window pages. ;----------------------------------------------------------------------------- MOV DX,16 ;Convert segment into MUL DX ; absolute address. MOV DI,OFFSET WINDOW_ADDR_BASE MOV CX,4 EMS_INIT_L2: MOV [DI],AX ;Save absolute address MOV [DI+2],DX ADD AX,16384 ;Point to next page address ADC DX,0 ADD DI,4 ;Point to next save address LOOP EMS_INIT_L2 ;----------------------------------------------------------------------------- ;Write the memory requirments to the device driver header ;----------------------------------------------------------------------------- POP BX ;Get back seg start of window ADD BX,1000H ;Add 64 Kbytes. XOR AX,AX ;Start at offset 0 PUSH ES CALL LOAD_HEADER ;Load memory requirments into POP ES ; request header. MOV DX,OFFSET PROGRAM ;Print copyright MOV AH,9 INT 21H ;----------------------------------------------------------------------------- ;Vector interrupt 15h to reserve the extended memory. ;----------------------------------------------------------------------------- PUSH ES MOV AX,3515H ;Get interrupt vector 15 INT 21H MOV OLD_INT15HO,BX ;save vector MOV OLD_INT15HS,ES POP ES MOV AX,2515H ;Set interrupt vector 15 MOV DX,OFFSET INT_15H INT 21H ;Call DOS ;----------------------------------------------------------------------------- ;Vector the 67h interrupt to the driver. Jump to final installation code. ;----------------------------------------------------------------------------- MOV AX,2567H ;Set interrupt vector 67 MOV DX,OFFSET INT_67H INT 21H ;Call DOS JMP INIT1 ;jump to final init. code. ;----------------------------------------------------------------------------- ;error routine to abort instalation. ;----------------------------------------------------------------------------- DISP_ERR: MOV DX,OFFSET ERRMSG ;Tell user that the driver is MOV AH,9 ; not loaded. INT 21H MOV AX,3000H ;Get DOS version INT 21H XCHG AL,AH ;Put number in proper order CMP AX,31EH ;See if DOS 3.3 MOV AX,OFFSET DRIVER_END ;Offset of device driver code MOV BX,CS ;If >3.3, abort install with JB ERROR_ABORT_SKIP ; 0 memory. Otherwise leave XOR AX,AX ; driver stub installed. ERROR_ABORT_SKIP: CALL LOAD_HEADER ;Load into request header MOV AX,8002 ;Indicate error in the RET ; driver return code. ;----------------------------------------------------------------------------- ;LOADHEADER loads the amount of memory needed into the request header. ;----------------------------------------------------------------------------- LOAD_HEADER PROC NEAR LES DI,[REQ_HEADADR] ;get addr of req hdr MOV WORD PTR ES:[DI.ADDRESS],AX ;Store offset and MOV WORD PTR ES:[DI.ADDRESS+2],BX ; code segment. RET LOAD_HEADER ENDP ;----------------------------------------------------------------------------- ;ScanFor - scans for first (non)occurance of character in line. ; Entry - BH - 0 = scan for non character, 1 = scan for character. ; DS:SI - string to scan. CX - length of string ; Exit - AH - 1 = end of line found. ;----------------------------------------------------------------------------- SCAN_FOR PROC NEAR XOR AH,AH ;Clear found flag SCAN_LOOP1: LODSB ;Get character OR BH,BH ;see if first match or JE SCAN_SKIP1 ; mismatch. 0 = match CMP AL,20H ;Check for noncharacter. JLE SCAN_SKIP4 JMP SHORT SCAN_SKIP2 SCAN_SKIP1: CMP AL,20H ;Check for character JG SCAN_SKIP4 SCAN_SKIP2: CMP AL,13 ;Check for CR JE SCAN_SKIP3 CMP AL,10 ;Check for LF JE SCAN_SKIP3 LOOP SCAN_LOOP1 SCAN_SKIP3: INC AH ;character not found SCAN_SKIP4: RET SCAN_FOR ENDP END_OF_CODE = $ INITIALIZE ENDP CODE ENDS END