[277] | 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 | SerialServerScan_ScanForServer: |
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| 28 | mov cx, 1 ; one sector, not scanning (default) |
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| 29 | |
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| 30 | test dx, dx |
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| 31 | jnz short SerialServerScan_CheckForServer_PortAndBaudInDX |
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| 32 | |
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| 33 | mov di,.scanPortAddresses-1 |
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| 34 | mov ch,1 ; tell server that we are scanning |
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| 35 | |
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| 36 | .nextPort: |
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| 37 | inc di ; load next port address |
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| 38 | xor dh, dh |
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| 39 | mov dl,[cs:di] |
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| 40 | eSHL_IM dx, 2 ; shift from one byte to two |
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| 41 | stc ; setup error code for exit |
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| 42 | jz .error |
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| 43 | |
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| 44 | ; |
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| 45 | ; Test for COM port presence, write to and read from registers |
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| 46 | ; |
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| 47 | push dx |
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| 48 | add dl,Serial_UART_lineControl |
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| 49 | mov al, 09ah |
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| 50 | out dx, al |
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| 51 | in al, dx |
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| 52 | pop dx |
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| 53 | cmp al, 09ah |
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| 54 | jnz .nextPort |
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| 55 | |
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| 56 | mov al, 0ch |
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| 57 | out dx, al |
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| 58 | in al, dx |
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| 59 | cmp al, 0ch |
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| 60 | jnz .nextPort |
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| 61 | |
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| 62 | ; |
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| 63 | ; Begin baud rate scan on this port... |
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| 64 | ; |
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| 65 | ; 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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| 66 | ; small jump between 9600 and 38800. These 6 were selected since we wanted to support 9600 baud and 115200, |
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| 67 | ; *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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| 68 | ; |
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| 69 | ; Starting with 30h, that means 30h (2400 baud), 18h (4800 baud), 0ch (9600 baud), and |
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| 70 | ; 04h (28800 baud), 02h (57600 baud), 01h (115200 baud) |
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| 71 | ; |
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| 72 | ; Note: hardware baud multipliers (2x, 4x) will impact the final baud rate and are not known at this level |
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| 73 | ; |
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| 74 | mov dh,030h * 2 ; multiply by 2 since we are about to divide by 2 |
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| 75 | mov dl,[cs:di] ; restore single byte port address for scan |
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| 76 | |
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| 77 | .nextBaud: |
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| 78 | shr dh,1 |
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| 79 | jz .nextPort |
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| 80 | cmp dh,6 ; skip from 6 to 4, to move from the top of the 9600 baud range |
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| 81 | jnz .testBaud ; to the bottom of the 115200 baud range |
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| 82 | mov dh,4 |
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| 83 | |
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| 84 | .testBaud: |
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| 85 | call SerialServerScan_CheckForServer_PortAndBaudInDX |
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| 86 | jc .nextBaud |
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| 87 | |
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| 88 | .error: |
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| 89 | ret |
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| 90 | |
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| 91 | .scanPortAddresses: db SERIAL_COM7_IOADDRESS >> 2 |
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| 92 | db SERIAL_COM6_IOADDRESS >> 2 |
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| 93 | db SERIAL_COM5_IOADDRESS >> 2 |
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| 94 | db SERIAL_COM4_IOADDRESS >> 2 |
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| 95 | db SERIAL_COM3_IOADDRESS >> 2 |
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| 96 | db SERIAL_COM2_IOADDRESS >> 2 |
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| 97 | db SERIAL_COM1_IOADDRESS >> 2 |
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| 98 | db 0 |
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| 99 | |
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| 100 | |
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| 101 | ;-------------------------------------------------------------------- |
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| 102 | ; SerialServer_CheckForServer_PortAndBaudInDX: |
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| 103 | ; Parameters: |
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| 104 | ; BH: Drive Select byte for Drive and Head Select Register |
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| 105 | ; 0xAx: Scan for drive, low nibble indicates drive |
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| 106 | ; 0x0: Scan for Server, independent of drives |
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| 107 | ; DX: Baud and Port |
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| 108 | ; CH: 1: We are doing a scan for the serial server |
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| 109 | ; 0: We are working off a specific port given by the user |
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| 110 | ; CL: 1, for one sector to read |
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| 111 | ; ES:SI: Ptr to buffer for return |
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| 112 | ; Returns: |
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| 113 | ; AH: INT 13h Error Code |
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| 114 | ; CF: Cleared if success, Set if error |
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| 115 | ; Corrupts registers: |
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| 116 | ; AL, BX |
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| 117 | ;-------------------------------------------------------------------- |
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| 118 | SerialServerScan_CheckForServer_PortAndBaudInDX: |
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| 119 | push bp ; setup fake SerialServer_Command |
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| 120 | |
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| 121 | push dx ; send port baud and rate, returned in inquire packet |
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| 122 | ; (and possibly returned in the drive identification string) |
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| 123 | |
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| 124 | push cx ; send number of sectors, and if it is on a scan or not |
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| 125 | |
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| 126 | mov bl,SerialServer_Command_Inquire ; protocol command onto stack with bh |
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| 127 | push bx |
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| 128 | |
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| 129 | mov bp,sp |
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| 130 | |
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| 131 | call SerialServer_SendReceive |
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| 132 | |
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| 133 | pop bx |
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| 134 | pop cx |
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| 135 | pop dx |
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| 136 | pop bp |
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| 137 | |
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| 138 | ret |
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| 139 | |
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