| 1 | ; Project name : Assembly Library
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| 2 | ; Description : Serial Server Support, Scan for Server
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| 3 | ;
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| 4 | ; This functionality is broken out from SerialServer as it may only be needed during
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| 5 | ; initialization to find a server, and then could be discarded, (for example the case
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| 6 | ; of a TSR).
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| 7 |
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| 8 | %include "SerialServer.inc"
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| 9 |
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| 10 | ; Section containing code
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| 11 | SECTION .text
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| 12 |
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| 13 | ;--------------------------------------------------------------------
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| 14 | ; SerialServerScan_ScanForServer:
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| 15 | ; Parameters:
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| 16 | ; BH: Drive Select byte for Drive and Head Select Register
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| 17 | ; 0xAx: Scan for drive, low nibble indicates drive
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| 18 | ; 0x0: Scan for Server, independent of drives
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| 19 | ; DX: Port and Baud to Scan for
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| 20 | ; 0: Scan a known set of ports and bauds
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| 21 | ; ES:SI: Ptr to buffer for return
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| 22 | ; Returns:
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| 23 | ; CF: Cleared if success, Set if error
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| 24 | ; Corrupts registers:
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| 25 | ; AL, BX, CX, DX, DI
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| 26 | ;--------------------------------------------------------------------
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| 27 | ALIGN JUMP_ALIGN
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| 28 | SerialServerScan_ScanForServer:
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| 29 | mov cx, 1 ; one sector, not scanning (default)
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| 30 |
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| 31 | test dx, dx
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| 32 | jnz short SerialServerScan_CheckForServer_PortAndBaudInDX
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| 33 |
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| 34 | mov di,.scanPortAddresses-1
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| 35 | mov ch,1 ; tell server that we are scanning
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| 36 |
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| 37 | .nextPort:
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| 38 | inc di ; load next port address
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| 39 | xor dh, dh
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| 40 | mov dl,[cs:di]
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| 41 | eSHL_IM dx, 2 ; shift from one byte to two
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| 42 | stc ; setup error code for exit
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| 43 | jz .error
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| 44 |
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| 45 | ;
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| 46 | ; Test for COM port presence, write to and read from registers
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| 47 | ;
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| 48 | push dx
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| 49 | add dl,Serial_UART_lineControl
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| 50 | mov al, 09ah
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| 51 | out dx, al
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| 52 | in al, dx
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| 53 | pop dx
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| 54 | cmp al, 09ah
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| 55 | jnz .nextPort
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| 56 |
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| 57 | mov al, 0ch
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| 58 | out dx, al
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| 59 | in al, dx
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| 60 | cmp al, 0ch
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| 61 | jnz .nextPort
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| 62 |
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| 63 | ;
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| 64 | ; Begin baud rate scan on this port...
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| 65 | ;
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| 66 | ; On a scan, we support 6 baud rates, starting here and going higher by a factor of two each step, with a
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| 67 | ; small jump between 9600 and 38800. These 6 were selected since we wanted to support 9600 baud and 115200,
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| 68 | ; *on the server side* if the client side had a 4x clock multiplier, a 2x clock multiplier, or no clock multiplier.
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| 69 | ;
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| 70 | ; Starting with 30h, that means 30h (2400 baud), 18h (4800 baud), 0ch (9600 baud), and
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| 71 | ; 04h (28800 baud), 02h (57600 baud), 01h (115200 baud)
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| 72 | ;
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| 73 | ; Note: hardware baud multipliers (2x, 4x) will impact the final baud rate and are not known at this level
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| 74 | ;
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| 75 | mov dh,030h * 2 ; multiply by 2 since we are about to divide by 2
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| 76 | mov dl,[cs:di] ; restore single byte port address for scan
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| 77 |
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| 78 | .nextBaud:
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| 79 | shr dh,1
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| 80 | jz .nextPort
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| 81 | cmp dh,6 ; skip from 6 to 4, to move from the top of the 9600 baud range
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| 82 | jnz .testBaud ; to the bottom of the 115200 baud range
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| 83 | mov dh,4
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| 84 |
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| 85 | .testBaud:
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| 86 | call SerialServerScan_CheckForServer_PortAndBaudInDX
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| 87 | jc .nextBaud
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| 88 |
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| 89 | .error:
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| 90 | ret
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| 91 |
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| 92 | .scanPortAddresses: db SERIAL_COM7_IOADDRESS >> 2
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| 93 | db SERIAL_COM6_IOADDRESS >> 2
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| 94 | db SERIAL_COM5_IOADDRESS >> 2
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| 95 | db SERIAL_COM4_IOADDRESS >> 2
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| 96 | db SERIAL_COM3_IOADDRESS >> 2
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| 97 | db SERIAL_COM2_IOADDRESS >> 2
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| 98 | db SERIAL_COM1_IOADDRESS >> 2
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| 99 | db 0
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| 100 |
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| 101 |
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| 102 | ;--------------------------------------------------------------------
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| 103 | ; SerialServer_CheckForServer_PortAndBaudInDX:
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| 104 | ; Parameters:
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| 105 | ; BH: Drive Select byte for Drive and Head Select Register
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| 106 | ; 0xAx: Scan for drive, low nibble indicates drive
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| 107 | ; 0x0: Scan for Server, independent of drives
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| 108 | ; DX: Baud and Port
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| 109 | ; CH: 1: We are doing a scan for the serial server
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| 110 | ; 0: We are working off a specific port given by the user
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| 111 | ; CL: 1, for one sector to read
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| 112 | ; ES:SI: Ptr to buffer for return
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| 113 | ; Returns:
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| 114 | ; AH: INT 13h Error Code
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| 115 | ; CF: Cleared if success, Set if error
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| 116 | ; Corrupts registers:
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| 117 | ; AL, BX
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| 118 | ;--------------------------------------------------------------------
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| 119 | ALIGN JUMP_ALIGN
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| 120 | SerialServerScan_CheckForServer_PortAndBaudInDX:
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| 121 | push bp ; setup fake SerialServer_Command
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| 122 |
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| 123 | push dx ; send port baud and rate, returned in inquire packet
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| 124 | ; (and possibly returned in the drive identification string)
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| 125 |
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| 126 | push cx ; send number of sectors, and if it is on a scan or not
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| 127 |
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| 128 | mov bl,SerialServer_Command_Inquire ; protocol command onto stack with bh
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| 129 | push bx
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| 130 |
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| 131 | mov bp,sp
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| 132 |
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| 133 | call SerialServer_SendReceive
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| 134 |
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| 135 | pop bx
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| 136 | pop cx
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| 137 | pop dx
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| 138 | pop bp
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| 139 |
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| 140 | ret
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| 141 |
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