[277] | 1 | ; Project name : Assembly Library |
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| 2 | ; Description : Serial Server Support |
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| 3 | |
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[376] | 4 | ; |
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| 5 | ; XTIDE Universal BIOS and Associated Tools |
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| 6 | ; Copyright (C) 2009-2010 by Tomi Tilli, 2011-2012 by XTIDE Universal BIOS Team. |
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| 7 | ; |
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| 8 | ; This program is free software; you can redistribute it and/or modify |
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| 9 | ; it under the terms of the GNU General Public License as published by |
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| 10 | ; the Free Software Foundation; either version 2 of the License, or |
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| 11 | ; (at your option) any later version. |
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| 12 | ; |
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| 13 | ; This program is distributed in the hope that it will be useful, |
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| 14 | ; but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 15 | ; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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| 16 | ; GNU General Public License for more details. |
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| 17 | ; Visit http://www.gnu.org/licenses/old-licenses/gpl-2.0.html |
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| 18 | ; |
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| 19 | |
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| 20 | |
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[277] | 21 | %include "SerialServer.inc" |
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[293] | 22 | |
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[277] | 23 | ; Section containing code |
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| 24 | SECTION .text |
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| 25 | |
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| 26 | ;-------------------------------------------------------------------- |
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[293] | 27 | ; SerialServer_SendReceive: |
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[277] | 28 | ; Parameters: |
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| 29 | ; DX: Packed I/O port and baud rate |
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| 30 | ; ES:SI: Ptr to buffer (for data transfer commands) |
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| 31 | ; SS:BP: Ptr to SerialServer_Command structure |
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| 32 | ; Returns: |
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| 33 | ; AH: INT 13h Error Code |
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| 34 | ; CX: Number of 512-byte blocks transferred |
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| 35 | ; CF: Cleared if success, Set if error |
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| 36 | ; Corrupts registers: |
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| 37 | ; AL, BX, CX, DX |
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| 38 | ;-------------------------------------------------------------------- |
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[293] | 39 | SerialServer_SendReceive: |
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| 40 | |
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[277] | 41 | push si |
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| 42 | push di |
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| 43 | push bp |
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| 44 | |
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| 45 | ; |
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| 46 | ; Unpack I/O port and baud from DPT |
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| 47 | ; Port to DX for the remainder of the routine (+/- different register offsets) |
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| 48 | ; Baud in CH until UART initialization is complete |
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| 49 | ; |
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| 50 | mov ch,dh |
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| 51 | xor dh,dh |
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| 52 | eSHL_IM dx, 2 ; shift from one byte to two |
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| 53 | |
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| 54 | mov al,[bp+SerialServer_Command.bSectorCount] |
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| 55 | mov ah,[bp+SerialServer_Command.bCommand] |
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[293] | 56 | |
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[277] | 57 | ; |
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| 58 | ; Command byte and sector count live at the top of the stack, pop/push are used to access |
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| 59 | ; |
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| 60 | push ax ; save sector count for return value |
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| 61 | push ax ; working copy on the top of the stack |
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| 62 | |
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[293] | 63 | %ifndef EXCLUDE_FROM_XTIDE_UNIVERSAL_BIOS ; DF already cleared in Int13h.asm |
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[277] | 64 | cld |
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[293] | 65 | %endif |
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[277] | 66 | |
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| 67 | ;---------------------------------------------------------------------- |
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| 68 | ; |
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| 69 | ; Initialize UART |
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| 70 | ; |
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| 71 | ; We do this each time since DOS (at boot) or another program may have |
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| 72 | ; decided to reprogram the UART |
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| 73 | ; |
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| 74 | mov bl,dl ; setup BL with proper values for read/write loops (BH comes later) |
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| 75 | |
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| 76 | mov al,83h |
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| 77 | add dl,Serial_UART_lineControl |
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| 78 | out dx,al |
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| 79 | |
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| 80 | mov al,ch |
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| 81 | mov dl,bl ; divisor low |
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| 82 | out dx,al |
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| 83 | |
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| 84 | xor ax,ax |
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| 85 | inc dx ; divisor high |
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| 86 | push dx |
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| 87 | out dx,al |
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| 88 | |
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| 89 | mov al,047h |
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| 90 | inc dx ; fifo |
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| 91 | out dx,al |
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| 92 | |
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| 93 | mov al,03h |
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| 94 | inc dx ; linecontrol |
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| 95 | out dx,al |
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| 96 | |
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| 97 | mov al,0bh |
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| 98 | inc dx ; modemcontrol |
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| 99 | out dx,al |
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| 100 | |
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| 101 | inc dx ; linestatus (no output now, just setting up BH for later use) |
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| 102 | mov bh,dl |
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| 103 | |
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| 104 | pop dx ; base, interrupts disabled |
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| 105 | xor ax,ax |
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| 106 | out dx,al |
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| 107 | |
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| 108 | ;---------------------------------------------------------------------- |
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| 109 | ; |
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| 110 | ; Send Command |
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| 111 | ; |
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| 112 | ; Sends first six bytes of IDEREGS_AND_INTPACK as the command |
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| 113 | ; |
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| 114 | push es ; save off real buffer location |
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| 115 | push si |
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| 116 | |
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| 117 | mov si,bp ; point to IDEREGS for command dispatch; |
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| 118 | push ss |
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| 119 | pop es |
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| 120 | |
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| 121 | mov di,0ffffh ; initialize checksum for write |
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| 122 | mov bp,di |
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| 123 | |
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| 124 | mov cx,4 ; writing 3 words (plus 1) |
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| 125 | |
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| 126 | cli ; interrupts off... |
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| 127 | |
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| 128 | call SerialServer_WriteProtocol.entry |
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| 129 | |
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| 130 | pop di ; restore real buffer location (note change from SI to DI) |
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| 131 | ; Buffer is primarily referenced through ES:DI throughout, since |
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| 132 | ; we need to store (read sector) faster than we read (write sector) |
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| 133 | pop es |
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| 134 | |
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| 135 | pop ax ; load command byte (done before call to .nextSector on subsequent iterations) |
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| 136 | push ax |
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| 137 | |
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[292] | 138 | %ifndef SERIALSERVER_NO_ZERO_SECTOR_COUNTS |
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[277] | 139 | test al,al ; if no sectors to be transferred, wait for the ACK checksum on the command |
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| 140 | jz .zeroSectors |
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[292] | 141 | %endif |
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[293] | 142 | |
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[277] | 143 | ; |
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| 144 | ; Top of the read/write loop, one iteration per sector |
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| 145 | ; |
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| 146 | .nextSector: |
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| 147 | mov si,0ffffh ; initialize checksum for read or write |
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| 148 | mov bp,si |
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| 149 | |
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| 150 | mov cx,0101h ; writing 256 words (plus 1) |
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| 151 | |
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| 152 | shr ah,1 ; command byte, are we doing a write? |
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| 153 | jnc .readEntry |
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| 154 | |
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| 155 | xchg si,di ; swap pointer and checksum, will be re-swap'ed in WriteProtocol |
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| 156 | call SerialServer_WriteProtocol.entry |
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| 157 | |
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| 158 | .zeroSectors: |
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| 159 | inc cx ; CX = 1 now (0 out of WriteProtocol) |
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| 160 | jmp .readEntry |
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| 161 | |
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| 162 | ;---------------------------------------------------------------------- |
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| 163 | ; |
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| 164 | ; Timeout |
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| 165 | ; |
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| 166 | ; To save code space, we use the contents of DL to decide which byte in the word to return for reading. |
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| 167 | ; |
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| 168 | .readTimeout: |
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| 169 | push ax ; not only does this push preserve AX (which we need), but it also |
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| 170 | ; means the stack has the same number of bytes on it as when we are |
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| 171 | ; sending a packet, important for error cleanup and exit |
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| 172 | mov ah,1 |
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| 173 | call SerialServer_WaitAndPoll_Read |
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| 174 | pop ax |
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| 175 | test dl,1 |
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| 176 | jz .readByte1Ready |
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| 177 | jmp .readByte2Ready |
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| 178 | |
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| 179 | ;---------------------------------------------------------------------------- |
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| 180 | ; |
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| 181 | ; Read Block (without interrupts, used when there is a FIFO, high speed) |
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| 182 | ; |
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| 183 | ; NOTE: This loop is very time sensitive. Literally, another instruction |
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| 184 | ; cannot be inserted into this loop without us falling behind at high |
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| 185 | ; speed (460.8K baud) on a 4.77Mhz 8088, making it hard to receive |
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| 186 | ; a full 512 byte block. |
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| 187 | ; |
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| 188 | .readLoop: |
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| 189 | stosw ; store word in caller's data buffer |
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| 190 | |
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| 191 | add bp, ax ; update Fletcher's checksum |
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| 192 | adc bp, 0 |
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| 193 | add si, bp |
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| 194 | adc si, 0 |
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| 195 | |
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| 196 | .readEntry: |
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| 197 | mov dl,bh |
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| 198 | in al,dx |
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| 199 | shr al,1 ; data ready (byte 1)? |
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| 200 | mov dl,bl ; get ready to read data |
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| 201 | jnc .readTimeout ; nope not ready, update timeouts |
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| 202 | |
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| 203 | ; |
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| 204 | ; Entry point after initial timeout. We enter here so that the checksum word |
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| 205 | ; is not stored (and is left in AX after the loop is complete). |
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| 206 | ; |
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| 207 | .readByte1Ready: |
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| 208 | in al, dx ; read data byte 1 |
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| 209 | |
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| 210 | mov ah, al ; store byte in ah for now |
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| 211 | |
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| 212 | ; |
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| 213 | ; note the placement of this reset of dl to bh, and that it is |
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| 214 | ; before the return, which is assymetric with where this is done |
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| 215 | ; above for byte 1. The value of dl is used by the timeout routine |
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| 216 | ; to know which byte to return to (.read_byte1_ready or |
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| 217 | ; .read_byte2_ready) |
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| 218 | ; |
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| 219 | mov dl,bh |
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| 220 | |
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| 221 | in al,dx |
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| 222 | shr al,1 ; data ready (byte 2)? |
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| 223 | jnc .readTimeout |
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| 224 | .readByte2Ready: |
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| 225 | mov dl,bl |
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| 226 | in al, dx ; read data byte 2 |
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| 227 | |
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| 228 | xchg al, ah ; ah was holding byte 1, reverse byte order |
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| 229 | |
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| 230 | loop .readLoop |
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| 231 | |
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| 232 | sti ; interrupts back on ASAP, between packets |
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| 233 | |
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| 234 | ; |
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| 235 | ; Compare checksums |
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| 236 | ; |
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| 237 | xchg ax,bp |
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| 238 | xor ah,al |
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| 239 | mov cx,si |
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| 240 | xor cl,ch |
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| 241 | mov al,cl |
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| 242 | cmp ax,bp |
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| 243 | jnz SerialServer_OutputWithParameters_Error |
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| 244 | |
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| 245 | pop ax ; sector count and command byte |
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| 246 | dec al ; decrement sector count |
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| 247 | push ax ; save |
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| 248 | jz SerialServer_OutputWithParameters_ReturnCodeInAL |
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| 249 | |
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| 250 | cli ; interrupts back off for ACK byte to host |
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| 251 | ; (host could start sending data immediately) |
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| 252 | out dx,al ; ACK with next sector number |
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| 253 | |
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| 254 | jmp short .nextSector |
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| 255 | |
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| 256 | ;--------------------------------------------------------------------------- |
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| 257 | ; |
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| 258 | ; Cleanup, error reporting, and exit |
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| 259 | ; |
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| 260 | |
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| 261 | ; |
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| 262 | ; Used in situations where a call is underway, such as with SerialServer_WaitAndPoll |
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| 263 | ; |
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| 264 | ALIGN JUMP_ALIGN |
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| 265 | SerialServer_OutputWithParameters_ErrorAndPop4Words: |
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| 266 | add sp,8 |
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| 267 | ;;; fall-through |
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| 268 | |
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| 269 | ALIGN JUMP_ALIGN |
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| 270 | SerialServer_OutputWithParameters_Error: |
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| 271 | ;---------------------------------------------------------------------- |
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| 272 | ; |
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| 273 | ; Clear read buffer |
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| 274 | ; |
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| 275 | ; In case there are extra characters or an error in the FIFO, clear it out. |
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| 276 | ; In theory the initialization of the UART registers above should have |
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| 277 | ; taken care of this, but I have seen cases where this is not true. |
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| 278 | ; |
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| 279 | xor cx,cx ; timeout this clearing routine, in case the UART isn't there |
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| 280 | .clearBuffer: |
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| 281 | mov dl,bh |
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| 282 | in al,dx |
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| 283 | mov dl,bl |
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| 284 | test al,08fh |
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| 285 | jz .clearBufferComplete |
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| 286 | test al,1 |
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| 287 | in al,dx |
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| 288 | loopnz .clearBuffer ; note ZF from test above |
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| 289 | |
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| 290 | .clearBufferComplete: |
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| 291 | mov al, 3 ; error return code and CF (low order bit) |
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| 292 | |
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| 293 | ALIGN JUMP_ALIGN |
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| 294 | SerialServer_OutputWithParameters_ReturnCodeInAL: |
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| 295 | %if 0 |
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| 296 | sti ; all paths here will already have interrupts turned back on |
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| 297 | %endif |
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| 298 | mov ah, al ; for success, AL will already be zero |
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[293] | 299 | |
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[277] | 300 | pop bx ; recover "ax" (command and count) from stack |
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| 301 | pop cx ; recover saved sector count |
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[293] | 302 | xor ch, ch |
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[277] | 303 | sub cl, bl ; subtract off the number of sectors that remained |
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| 304 | |
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| 305 | pop bp |
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| 306 | pop di |
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| 307 | pop si |
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| 308 | |
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| 309 | shr ah, 1 ; shift down return code and CF |
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| 310 | |
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| 311 | ret |
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| 312 | |
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| 313 | ;-------------------------------------------------------------------- |
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| 314 | ; SerialServer_WriteProtocol |
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| 315 | ; |
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| 316 | ; NOTE: As with its read counterpart, this loop is very time sensitive. |
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| 317 | ; Although it will still function, adding additional instructions will |
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| 318 | ; impact the write throughput, especially on slower machines. |
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| 319 | ; |
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| 320 | ; Parameters: |
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| 321 | ; ES:SI: Ptr to buffer |
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| 322 | ; CX: Words to write, plus 1 |
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| 323 | ; BP/DI: Initialized for Checksum (-1 in each) |
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| 324 | ; DH: I/O Port high byte |
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| 325 | ; BX: LineStatus Register address (BH) and Receive/Transmit Register address (BL) |
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| 326 | ; Returns: |
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| 327 | ; BP/SI: Checksum for written bytes, compared against ACK from server in .readLoop |
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| 328 | ; CX: Zero |
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| 329 | ; DL: Receive/Transmit Register address |
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| 330 | ; ES:DI: Ptr to buffer |
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| 331 | ; Corrupts registers: |
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| 332 | ; AX |
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| 333 | ;-------------------------------------------------------------------- |
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| 334 | ALIGN JUMP_ALIGN |
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| 335 | SerialServer_WriteProtocol: |
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| 336 | .writeLoop: |
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| 337 | es lodsw ; fetch next word |
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| 338 | |
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| 339 | out dx,al ; output first byte |
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| 340 | |
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| 341 | add bp,ax ; update checksum |
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| 342 | adc bp,0 |
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| 343 | add di,bp |
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| 344 | adc di,0 |
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| 345 | |
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| 346 | mov dl,bh ; transmit buffer empty? |
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| 347 | in al,dx |
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| 348 | test al,20h |
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| 349 | jz .writeTimeout2 ; nope, use our polling routine |
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| 350 | |
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| 351 | .writeByte2Ready: |
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| 352 | mov dl,bl |
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| 353 | mov al,ah ; output second byte |
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| 354 | out dx,al |
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| 355 | |
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| 356 | .entry: |
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| 357 | mov dl,bh ; transmit buffer empty? |
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| 358 | in al,dx |
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| 359 | test al,20h |
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| 360 | mov dl,bl |
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| 361 | jz .writeTimeout1 ; nope, use our polling routine |
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| 362 | |
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| 363 | .writeByte1Ready: |
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| 364 | loop .writeLoop |
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| 365 | |
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| 366 | mov ax,di ; fold Fletcher's checksum and output |
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| 367 | xor al,ah |
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| 368 | out dx,al ; byte 1 |
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| 369 | |
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| 370 | call SerialServer_WaitAndPoll_Write |
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| 371 | |
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| 372 | mov ax,bp |
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| 373 | xor al,ah |
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| 374 | out dx,al ; byte 2 |
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| 375 | |
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| 376 | xchg si,di ; preserve checksum word in si, move pointer back to di |
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| 377 | |
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| 378 | ret |
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| 379 | |
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| 380 | .writeTimeout2: |
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| 381 | mov dl,ah ; need to preserve AH, but don't need DL (will be reset upon return) |
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| 382 | call SerialServer_WaitAndPoll_Write |
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| 383 | mov ah,dl |
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| 384 | jmp .writeByte2Ready |
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| 385 | |
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| 386 | .writeTimeout1: |
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[293] | 387 | ePUSH_T ax, .writeByte1Ready ; return address for ret at end of SC_writeTimeout2 |
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[277] | 388 | ;;; fall-through |
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| 389 | |
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| 390 | ;-------------------------------------------------------------------- |
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| 391 | ; SerialServer_WaitAndPoll |
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| 392 | ; |
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| 393 | ; Parameters: |
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| 394 | ; AH: UART_LineStatus bit to test (20h for write, or 1h for read) |
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| 395 | ; One entry point fills in AH with 20h for write |
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| 396 | ; DX: Port address (OK if already incremented to UART_lineStatus) |
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[293] | 397 | ; BX: |
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[277] | 398 | ; Stack: 2 words on the stack below the command/count word |
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| 399 | ; Returns: |
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| 400 | ; Returns when desired UART_LineStatus bit is cleared |
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| 401 | ; Jumps directly to error exit if timeout elapses (and cleans up stack) |
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| 402 | ; Corrupts registers: |
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| 403 | ; AX |
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| 404 | ;-------------------------------------------------------------------- |
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| 405 | |
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| 406 | SerialServer_WaitAndPoll_SoftDelayTicks EQU 20 |
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| 407 | |
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| 408 | ALIGN JUMP_ALIGN |
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| 409 | SerialServer_WaitAndPoll_Write: |
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| 410 | mov ah,20h |
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| 411 | ;;; fall-through |
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| 412 | |
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| 413 | ALIGN JUMP_ALIGN |
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| 414 | SerialServer_WaitAndPoll_Read: |
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| 415 | push cx |
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| 416 | push dx |
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| 417 | |
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| 418 | ; |
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| 419 | ; We first poll in a tight loop, interrupts off, for the next character to come in/be sent |
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| 420 | ; |
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| 421 | xor cx,cx |
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| 422 | .readTimeoutLoop: |
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| 423 | mov dl,bh |
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| 424 | in al,dx |
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| 425 | test al,ah |
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| 426 | jnz .readTimeoutComplete |
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| 427 | loop .readTimeoutLoop |
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| 428 | |
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| 429 | ; |
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| 430 | ; If that loop completes, then we assume there is a long delay involved, turn interrupts back on |
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| 431 | ; and wait for a given number of timer ticks to pass. |
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| 432 | ; |
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| 433 | sti |
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| 434 | mov cl,SerialServer_WaitAndPoll_SoftDelayTicks |
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| 435 | %ifndef SERIALSERVER_TIMER_LOCATION |
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| 436 | call Timer_InitializeTimeoutWithTicksInCL |
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| 437 | %else |
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| 438 | push ax |
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| 439 | push bx |
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| 440 | mov ax,SerialServer_WaitAndPoll_SoftDelayTicks |
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| 441 | mov bx,SERIALSERVER_TIMER_LOCATION |
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| 442 | call TimerTicks_InitializeTimeoutFromAX |
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| 443 | pop bx |
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| 444 | pop ax |
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| 445 | %endif |
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[293] | 446 | |
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[277] | 447 | .WaitAndPoll: |
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| 448 | %ifndef SERIALSERVER_TIMER_LOCATION |
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| 449 | call Timer_SetCFifTimeout |
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| 450 | %else |
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| 451 | push ax |
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| 452 | push bx |
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| 453 | mov bx,SERIALSERVER_TIMER_LOCATION |
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| 454 | call TimerTicks_GetTimeoutTicksLeftToAXfromDSBX |
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| 455 | pop bx |
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| 456 | pop ax |
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[293] | 457 | %endif |
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[277] | 458 | jc SerialServer_OutputWithParameters_ErrorAndPop4Words |
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| 459 | in al,dx |
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| 460 | test al,ah |
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| 461 | jz .WaitAndPoll |
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| 462 | cli |
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| 463 | |
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| 464 | .readTimeoutComplete: |
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| 465 | pop dx |
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| 466 | pop cx |
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| 467 | ret |
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| 468 | |
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| 469 | |
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