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Assembly Source File | 1986-07-14 | 16.3 KB | 393 lines

Page 55,132 Title SEND - Send a file using XMODEM protocol SPECIAL Equ 0 ;If true, include data size in block If SPECIAL BLOCK Struc B_SOH Db 001H ;Start of header B_BLK1 Db 000H ;Block number B_BLK2 Db 0FFH ;(Block number)' B_CNT Db ? ;Count of bytes used in the data area B_DATA Db 128 Dup (?) ;The data area B_CHKSUM Db ? ;Checksum of the data BLOCK Ends Else BLOCK Struc B_SOH Db 001H ;Start of header B_BLK1 Db 000H ;Block number B_BLK2 Db 0FFH ;(Block number)' B_DATA Db 128 Dup (?) ;The data area B_CHKSUM Db ? ;Checksum of the data BLOCK Ends Endif ERROR Macro N Mov AH,09H ;Display the error message Lea DX,ERRMSG&N ; Int 021H ; Mov AX,04C10H+N ;And leave Int 021H ; Endm CODE Segment Public 'CODE' CODE Ends DATA Segment Public 'DATA' BAUD_TABLE Label Word Dw 9600 ; Dw 4800 ; Dw 2400 ; Dw 1200 ; Dw 600 ; Dw 300 ; Dw 150 ; Dw 110 ; FILENAME Db 64 Dup (0) ;Name of file to send BUFFER BLOCK <> ;The block buffer ERRMSG0 Db '?No output file specified',13,10,'$' ERRMSG1 Db '?Unable to create output file',13,10,'$' ERRMSG2 Db '?Invalid baud rate specified',13,10,'$' ERRMSG3 Db '?Transmitter time-out occurred',13,10,'$' ERRMSG4 Db '?Error while writing the output file',13,10,'$' ERRMSG5 Db '^C',13,10,'%Reception aborted via control-C',13,10,'$' TXTMSG1 Db 'Waiting for transmitter...',13,10,'$' TXTMSG2 Db 'Block number ' TXTNUM2 Db '0 ',13,'$' TXTMSG3 Db 10,'Reception complete',13,10,'$' TXTMSG4 Db 'No retries needed',13,10,'$' TXTMSG5 Db 'Retry count was ' TXTNUM5 Db '0 ',13,10,'$' MODE Db 11101011B ;9600 baud, odd parity, 1 stop bit, ;8 bit character BLOCK_COUNT Dw 0 ;Total block count RETRY_COUNT Dw 0 ;Retry count BLK_NUM Db 001H ;8 bit block number expected. DATA Ends STACK Segment Stack 'STACK' Dw 128 Dup (?) ;Program stack STACK Ends CODE Segment Public 'CODE' Assume CS:CODE,DS:Nothing,ES:Nothing,SS:STACK MAIN Proc Near Sti ;Enable interrupts Mov AX,DATA ;Set up ES Mov ES,AX ; Assume ES:DATA Cld ;Make sure the direction flag is clear Mov SI,080H ;Use SI to get the file name Lodsb ;Get the length Or AL,AL ;Is there anything?? Jnz MAIN01 ;Yes. Proceed MAIN00: Mov AX,ES ;Set up DS Mov DS,AX ; Assume DS:DATA ERROR 0 ;Nope. Die! Assume DS:Nothing MAIN01: Cbw ;Make it a word count Mov CX,AX ;Copy to CX MAIN05: Jcxz MAIN00 ;If nothing left, error! Dec CX ;Decrement the character count Lodsb ;And get the character Cmp AL,020H ;Space or less?? Ja MAIN10 ;Nope. Start the file name Jmp Short MAIN05 ;Try again... MAIN10: Lea DI,FILENAME ;Point DI to the file name buffer MAIN11: Stosb ;Store the character Jcxz MAIN20 ;Got the file name. Open the file Dec CX ;Decrement the character count Lodsb ;Get the next character Cmp AL,020H ;Is it a displayable character Ja MAIN11 ;Yes. Put it in the file name MAIN13: Jcxz MAIN20 ;No more characters? Dec CX ;Decrement the count Lodsb ;Get another character Cmp AL,020H ;Space or less?? Ja MAIN15 ;Yes. See if it's a number Jmp Short MAIN13 ;Keep looking MAIN15: Xor DX,DX ;Clear DX MAIN16: Cmp AL,'0' ;Is this a digit?? Jae MAIN18 ;Yes. MAIN17: ERROR 2 ;Not a valid baud rate MAIN18: Cmp AL,'9' ;Still a digit?? Ja MAIN17 ;Nope. Sub AL,'0' ;Convert to binary Cbw ;Convert to a word Shl DX,1 ;Double the previous number Mov BX,DX ;Save in BX for a bit Shl DX,1 ; Shl DX,1 ; Add DX,BX ;Now DX = (Old DX)*10 Add DX,AX ;Add in the last digit Jcxz MAIN19 ;All done. Dec CX ;Decrement the character count Lodsb ;And get a character Cmp AL,020H ;Space or less? Ja MAIN16 ; MAIN19: Mov AX,DX ;Put the baud rate in AX Lea DI,BAUD_TABLE ;Point to the baud rate table Mov CX,8 ;Eight entries in the table Repne Scasw ;Look for this baud rate Jne MAIN17 ;No good! Die! Mov AL,CL ;Get the index Mov CL,5 ;And position it Shl AL,CL ; Or AL,00001011B ;Odd parity, 1 stop bit, 8 bit character Mov MODE,AL ;And save it MAIN20: Mov AX,ES ;Set up DS Mov DS,AX ; Assume DS:DATA Mov AH,03CH ;Create the file specified Xor CX,CX ;With no attributes Lea DX,FILENAME ; Int 021H ; Jnc MAIN25 ;Proceed! ERROR 1 ;Couldn't create the file MAIN25: Mov BX,AX ;Put the handle in BX Xor AH,AH ;Initialize the RS232 channel Mov AL,MODE ; Xor DX,DX ;On channel zero Int 014H ; Mov AH,09H ;Display the "Waiting..." message Lea DX,TXTMSG1 ; Int 021H ; Mov CX,64 ;This shall be our original timeout MAIN30: Mov AH,06H ;See if a character is waiting Mov DL,0FFH ; Int 021H ; Jz MAIN32 ;Nope. Cmp AL,3 ;Is it a control-C?? Jne MAIN32 ; Mov AH,03EH ;Close the input file Int 021H ; ERROR 5 ;And die MAIN32: Mov AX,0115H ;Send a NAK to the transmitter Xor DX,DX ;(channel 0) Int 014H ; Push CX ;Save CX on the stack Call GET_BLOCK ;Get a block of data Pop CX ;Restore CX Jnc MAIN35 ;Got one. Go check it. MAIN31: Loop MAIN30 ;Repeat until CX = 0 Mov AH,03EH ;Close the input file Int 021H ; ERROR 3 ;And die! MAIN35: Cmp BUFFER.B_SOH,04H ;Is this the end of the file?? Je MAIN80 ;Yes. Close the file and leave Lea DI,TXTNUM2 ;Fill in the block number Mov AX,BLOCK_COUNT ; Call FILL_NUM ; Mov AH,09H ;Display the block number Lea DX,TXTMSG2 ; Int 021H ; Mov AH,040H ;Write the file... If SPECIAL Mov CL,BUFFER.B_CNT ;This many bytes only! Xor CH,CH ; Else Mov CX,128 ;Up to 128 bytes Endif Lea DX,BUFFER.B_DATA ;From our buffer Int 021H ; Jnc MAIN40 ;Got it; now ship it Mov AH,03EH ;Close the input file Int 021H ; ERROR 4 ;And die (for some unknown reason) MAIN40: Mov AX,0105H ;Send an ACK Xor DX,DX ; Int 014H ; MAIN42: Call GET_BLOCK ;Get another block Jnc MAIN35 ;Check for EOF. Mov AX,0115H ;Send another NAK (just in case) Xor DX,DX ; Int 014H ; Jmp Short MAIN42 ;And try again ; ; End of file... ; MAIN80: Mov AX,0105H ;Send a final ACK Xor DX,DX ; Int 014H ; Mov AH,09H ;Display the EOT message Lea DX,TXTMSG3 ; Int 021H ; Mov AH,03EH ;Close the input file Int 021H ; Cmp RETRY_COUNT,0 ;Did we have to do any retries?? Mov AH,09H ;No retries needed Lea DX,TXTMSG4 ; Int 021H ; Jmp Short MAIN99 ;Leave MAIN95: Lea DI,TXTNUM5 ;Point to the buffer Mov AX,RETRY_COUNT ;Get the count Call FILL_NUM ; Mov AH,09H ;And display the message Lea DX,TXTMSG5 ; Int 021H ; MAIN99: Mov AX,04C00H ;And leave Int 021H ; MAIN Endp ; ; ; FILL_NUM Proc Near Xor CX,CX ;Clear the character count Mov SI,10 ;Use SI to divide with FILL10: Xor DX,DX ; Div SI ;Divide DX:AX by SI (10) Add DL,'0' ;Convert DL to ASCII Push DX ;Save it on the stack Inc CX ;Increment the character count Or AX,AX ;Any more to do?? Jnz FILL10 ;Yes. Keep going Cld ;(just to be sure) FILL20: Pop AX ;Get a character from the stack Stosb ;And store it Loop FILL20 ;Repeat CX times Ret ;And return FILL_NUM Endp ; ; Get a block from the transmitter ; GET_BLOCK Proc Near Cld ;(just to be sure) Lea DI,BUFFER ;Point to the buffer Mov CX,20 ;Time out for the first byte GETB10: Mov AH,06H ;See if a character is waiting Mov DL,0FFH ; Int 021H ; Jz GETB12 ;Nope. Cmp AL,3 ;Is it a control-C?? Jne GETB12 ; Mov AH,03EH ;Close the input file Int 021H ; ERROR 5 ;And die GETB12: Mov AH,02H ;Get a character Xor DX,DX ; Int 014H ; Test AH,08EH ;Any errors?? Jnz GETB14 ;Yup. Ignore it! Cmp AL,01H ;SOH?? Je GETB20 ;Yes. Start the block Cmp AL,04H ;End-of-text?? Je GETB15 ;Yes. Return it. Jmp Short GETB12 ;Wait for another character GETB14: Loop GETB10 ;Repeat until CX = 0 Stc ;Set the carry Ret ;And return GETB15: Stosb ;Store the EOT Clc ;Clear carry... Ret ;...and return GETB20: Mov CX,(Size BLOCK-1) ;Repeat for the entire block Stosb ;Store the SOH GETB22: Mov SI,4 ;Use SI for a timeout count GETB24: Mov AH,02H ;Wait for another character Xor DX,DX ; Int 014H ; Test AH,080H ;Time-out?? Jz GETB26 ;Nope. Dec SI ;Decrement the time-out count Jnz GETB24 ;And try again Jmp SEND_RETRY ;Send a retry GETB26: Stosb ;Store the character Loop GETB22 ;And try again Mov AL,BLK_NUM ;Get the expected block number Cmp AL,BUFFER.B_BLK1 ;Is this it?? Jne SEND_RETRY ;Nope. Xor AL,0FFH ;Complement AL Cmp AL,BUFFER.B_BLK2 ;Double check Jne SEND_RETRY ;Nope. Lea SI,BUFFER.B_DATA ;Compute the checksum Xor AH,AH ;Clear AH Xor DX,DX ;Keep the checksum in DX Mov CX,128 ;Repeat for 128 bytes GETB30: Lodsb ;Get a byte Add DX,AX ;Add it to DX Loop GETB30 ;And repeat Mov AX,DX ;Put the sum in AX Mov DL,255 ;Now divide by 255 Div DL ; Cmp BUFFER.B_CHKSUM,AH ;See if the check sum is O.K. Jne SEND_RETRY ;Nope. Send a retry Inc BLK_NUM ;Increment the expected block number Inc BLOCK_COUNT ;And the block count Clc ; Ret ;Otherwise return with carry clear SEND_RETRY: Mov AX,0115H ;Send a NAK Xor DX,DX ; Int 014H ; Inc RETRY_COUNT ;Increment the retry count Jmp GET_BLOCK ;And try all over again GET_BLOCK Endp CODE Ends End MAIN