þa‹RþwQþ mP9þhý oPþ nSystem-wide$PAGEWIDTH(96) NAME DISKIO ; ; DISKIO.ASM ; ; ; ;These assembly language routines should be called ;with the following PLM LARGE calls: ; ; ; DataOut : PROCEDURE (data); ; DCL data BYTE; ; END; ; ; DataIn : PROCEDURE (location); ; DCL location POINTER; ; END; ; ; SelectDrive : PROCEDURE (driveNo,SelectBit); ; DCL driveNo BYTE; ; DCL SelectBit BYTE; ; END; ; ; SetUpDMA: PROCEDURE (command,pBuffer,length); ; DCL command WORD; ; DCL pBuffer POINTER; ; DCL length WORD; ; END; ; ; WaitForDMADone: PROCEDURE WORD; ; END; ; ; FastRead: PROCEDURE (pCommand,pBuffer) WORD; ; DCL pCommand POINTER; ; DCL pBuffer POINTER; ; END; ; CGROUP GROUP CODE DGROUP GROUP DATA DATA SEGMENT PUBLIC 'DATA' DATA ENDS CONST SEGMENT PUBLIC 'CONST' ;DMA register addresses WriteTab DW LoDMASrc0, HiDMASrc0 ReadTab DW LoDMADest0, HiDMADest0 DW LoDMASrc0, HiDMASrc0 CONST ENDS CODE SEGMENT PUBLIC 'CODE' PUBLIC DataIn PUBLIC DataOut PUBLIC SelectDrive PUBLIC SetUpDMA PUBLIC WaitForDMADone PUBLIC FastRead DSA STRUC ; DEFINE CALL PARAMETER STRUCTURE OldBP DW ? ; old BP marker OldDS DW ? ; old DS RetIP DW ? ; return IP RetCS DW ? ; return CS DLen DW ? ; return CS Buffr DD ? ; pointer to data buffer Command DW ? ; read or write DSA ENDS DSB STRUC ; DEFINE CALL PARAMETER STRUCTURE OBP DW ? ; old BP marker RIP DW ? ; return IP RCS DW ? ; return CS pBuffr DD ? ; pointer to data buffer pCmd DD ? ; pointer to command block DSB ENDS PerBusSeg EQU 0d000h PerBusBoxAddr EQU 100h PerBusDataREAD EQU 206h PerBusDataWRITE EQU 206H PerBusStatus EQU 202H PerBusSelect EQU 200H PerBusHi EQU 000DH STOPDMA EQU 04h REQMSK EQU 020H PTSET EQU 0FFH ; POSITIVE TRUE SET VALUE PTCLR EQU 000H ; POSITIVE TRUE CLEAR VALUE NTSET EQU PTCLR ; NEGATIVE TRUE SET VALUE NTCLR EQU PTSET ; NEGATIVE TRUE CLEAR VALUE ONE EQU 001H ; ;DMA decodes ; DMACont0 EQU 0FFCAH HiDMADest0 EQU 0FFC6H LoDMADest0 EQU 0FFC4H HiDMASrc0 EQU 0FFC2H LoDMASrc0 EQU 0FFC0H DMATC0 EQU 0FFC8H EnDMAWrit0 EQU 097A6H EnDMARead0 EQU 0B366H DoneMsk EQU 0002H RidSeg EQU 0FFF0H ; ;Other decodes ; TimeoutValue EQU 0FFFH ddRead EQU 4 eReqTimeOut EQU 253 DMALength EQU 2202h ; 8.5k + two status bytes ASSUME CS:CGROUP, DS:DGROUP, SS:DGROUP SetUpDMA PROC FAR; PUSH DS ; DATA SEGMENT POINTER PUSH BP ; PLM PROCEDURE PROLOGUE MOV BP,SP ; SAVE STACK MARKER MOV AX, SEG WriteTab ;set up DMA register address segment MOV ES,AX ; now get the buffer pointer from ; the stack and place the lower 16 bits ; in AX and the upper 4 bits in the lsb's ; of CL LDS BX,[BP].BUFFR ;put buffer addr in BX MOV AX,DS ;get upper 4 address MOV CL,4 ;bits in lsb's of AX ROL AX,CL MOV CL,AL ;save upper 4 bits AND AX,RidSeg ;mask out upper 4 ADD AX,BX ;bits and get lower ;16 bits ADC CL,00 ;if there was a carry ;add 1 to the upper ;bits CMP [BP].Command,ddread ;decide if read or write JE SetUpRead SetUpWrite: MOV SI, OFFSET WriteTab ;get correct table MOV BX, EnDMAWrit0 ;save correct command JMP OutputSetUp SetUpRead: MOV SI, OFFSET ReadTab ;get correct table MOV BX, EnDMARead0 ;save correct command OutputSetUp: MOV DX,ES:[SI] ;output lower 16 bits of pointer INC SI INC SI OUT DX,AX MOV AL,CL ;output upper 4 bits of pointer MOV DX,ES:[SI] INC SI INC SI OUT DX,AX MOV DX,ES:[SI] ;output low per bus address INC SI INC SI MOV AX,PerBusDataRead OUT DX,AX MOV DX,ES:[SI] ;output high per bus address MOV AX,PerBusHi OUT DX,AX MOV DX,DMATC0 ;set up TC register MOV AX,[BP].DLen OUT DX,AX MOV DX,DMACont0 ;enable DMA with saved command MOV AX,BX OUT DX,AX POP BP POP DS RET 8 SetUpDMA ENDP WaitForDMADone PROC FAR; MOV DX,DMACont0 MOV CX,0 WaitDMA: IN AX,DX AND AX,DoneMsk JZ DMADone LOOP WaitDMA MOV DX,DMACont0 ; disable DMA MOV AX,STOPDMA OUT DX,AX MOV AX,eReqTimeOut JMP WaitDone DMADone: XOR AX, AX ; clear errorcode WaitDone: RET WaitForDMADone ENDP SelectDrive PROC FAR PUSH BP MOV BP,SP MOV BX,[BP+6] ; SELECT DATABYTE MOV AX,[BP+8] ; BOX NUMBER NOT AL ; invert box number MOV CX,PerBusSeg MOV ES,CX MOV ES:BYTE PTR PerBusBoxAddr,AL MOV ES:BYTE PTR PerBusSelect,BL POP BP RET 4 SELECTDRIVE ENDP DATAIN PROC FAR PUSH BP PUSH DS MOV BP,SP LDS DI,DWORD PTR [BP+8] ; Get Data Buffer MOV AX,PerBusSeg MOV ES,AX LOOPRI: MOV AL,ES: BYTE PTR PerBusStatus AND AL,REQMSK JZ LOOPRI MOV AL,ES: BYTE PTR PerBusDataREAD MOV DS:[DI],AL ; Store data byte POP DS POP BP RET 4 DATAIN ENDP DATAOUT PROC FAR PUSH BP MOV BP,SP MOV BX,[BP+6] ; DATABYTE TO OUTPUT in BL PUSH ES MOV AX,PerBusSeg MOV ES,AX LOOPRO: MOV AL,ES: BYTE PTR PerBusStatus AND AL,REQMSK JZ LOOPRO MOV ES: BYTE PTR PerBusDataWRITE,BL POP ES POP BP RET 2 DATAOUT ENDP CMDOUT PROC NEAR PUSH ES MOV AX,PerBusSeg MOV ES,AX LOOCO: MOV AL,ES: BYTE PTR PerBusStatus AND AL,REQMSK JZ LOOCO MOV ES: BYTE PTR PerBusDataWRITE,BL POP ES RET CMDOUT ENDP FastRead PROC FAR ; PUSH BP ; PLM PROCEDURE PROLOGUE MOV BP,SP ; SAVE STACK MARKER ; now get the command buffer pointer from ; the stack and output the Peripheral bus commands LES SI,[BP].pCmd ;put buffer addr in BX MOV BL,ES:[SI] ;output Command CALL CMDOut INC SI MOV BL,ES:[SI] ;output LUN + Uaddr CALL CMDOut INC SI MOV BL,ES:[SI] ;output MAddr CALL CMDOut INC SI MOV BL,ES:[SI] ;output lAddr CALL CMDOut INC SI MOV BL,ES:[SI] ;output # of blocks CALL CMDOut INC SI MOV BL,ES:[SI] ;output Control word CALL CMDOut ; ; Setup DMA for 8.5 k Read ; MOV AX,ddRead ; Read command to DMA PUSH AX LES SI,[BP].pBuffr ; get data buffer address PUSH ES PUSH SI MOV AX,DMALength ; DMA xfer length PUSH AX CALL SetupDMA ; ; Wait for DMA to be completed ; HLT MOV AX,0h ; ; Error word already in AX ; POP BP RET 8 FastRead ENDP CODE ENDS END