| 1 | ;
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| 2 | ; PMIO.ASM -- File I/O for the kernel
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| 3 | ;
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| 4 | ; Copyright (c) 1991-1995 by Eberhard Mattes
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| 5 | ;
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| 6 | ; This file is part of emx.
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| 7 | ;
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| 8 | ; emx is free software; you can redistribute it and/or modify it
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| 9 | ; under the terms of the GNU General Public License as published by
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| 10 | ; the Free Software Foundation; either version 2, or (at your option)
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| 11 | ; any later version.
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| 12 | ;
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| 13 | ; emx 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 | ;
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| 18 | ; You should have received a copy of the GNU General Public License
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| 19 | ; along with emx; see the file COPYING. If not, write to
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| 20 | ; the Free Software Foundation, 59 Temple Place - Suite 330,
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| 21 | ; Boston, MA 02111-1307, USA.
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| 22 | ;
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| 23 | ; See emx.asm for a special exception.
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| 24 | ;
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| 25 |
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| 26 | INCLUDE EMX.INC
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| 27 | INCLUDE SIGNAL.INC
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| 28 | INCLUDE PROCESS.INC
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| 29 |
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| 30 | PUBLIC DEBUG_FLAG
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| 31 | PUBLIC OPEN, SEEK, READ, WRITE, CREATE_TMP, CLOSE
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| 32 | PUBLIC FORCE_STDOUT, FIND_FILE, ACCESS
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| 33 |
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| 34 |
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| 35 | SV_DATA SEGMENT
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| 36 |
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| 37 | DEBUG_FLAG DB FALSE
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| 38 | STDOUT_NAME DB "CON", 0
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| 39 |
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| 40 | SV_DATA ENDS
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| 41 |
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| 42 |
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| 43 |
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| 44 | PMIO_BEGIN MACRO
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| 45 | PUSH PROCESS_PTR
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| 46 | MOV PROCESS_PTR, NO_PROCESS
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| 47 | ENDM
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| 48 |
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| 49 | PMIO_END MACRO
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| 50 | POP PROCESS_PTR
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| 51 | ENDM
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| 52 |
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| 53 | SV_CODE SEGMENT
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| 54 |
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| 55 | ASSUME CS:SV_CODE, DS:NOTHING, ES:SV_DATA
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| 56 |
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| 57 |
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| 58 | ;
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| 59 | ; Open file
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| 60 | ;
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| 61 | ; In: AX:EDX Pointer to name
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| 62 | ; CL Access code
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| 63 | ;
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| 64 | ; Out: CY Error
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| 65 | ; EAX File handle or error code
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| 66 | ;
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| 67 | ASSUME DS:SV_DATA
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| 68 | OPEN PROC NEAR
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| 69 | PMIO_BEGIN
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| 70 | PUSH DS
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| 71 | MOV DS, AX
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| 72 | ASSUME DS:NOTHING
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| 73 | MOV AH, 3DH
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| 74 | MOV AL, CL
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| 75 | INT 21H
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| 76 | POP DS
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| 77 | ASSUME DS:SV_DATA
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| 78 | PMIO_END
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| 79 | RET
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| 80 | OPEN ENDP
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| 81 |
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| 82 | ;
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| 83 | ; Close file
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| 84 | ;
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| 85 | ; In: BX File handle
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| 86 | ;
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| 87 | ASSUME DS:SV_DATA
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| 88 | CLOSE PROC NEAR
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| 89 | PMIO_BEGIN
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| 90 | MOVZX EBX, BX
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| 91 | MOV AH, 3EH
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| 92 | INT 21H
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| 93 | PMIO_END
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| 94 | RET
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| 95 | CLOSE ENDP
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| 96 |
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| 97 | ;
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| 98 | ; Create temporary file
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| 99 | ;
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| 100 | ; In: AX:EDX Pointer to name
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| 101 | ;
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| 102 | ASSUME DS:SV_DATA
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| 103 | CREATE_TMP PROC NEAR
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| 104 | PMIO_BEGIN
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| 105 | PUSH DS
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| 106 | PUSH ECX
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| 107 | MOV CX, 0000H
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| 108 | MOV DS, AX
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| 109 | ASSUME DS:NOTHING
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| 110 | MOV AH, 5AH
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| 111 | INT 21H
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| 112 | POP ECX
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| 113 | POP DS
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| 114 | ASSUME DS:SV_DATA
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| 115 | PMIO_END
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| 116 | RET
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| 117 | CREATE_TMP ENDP
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| 118 |
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| 119 |
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| 120 | ;
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| 121 | ; In: BX File handle
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| 122 | ; EDX Position
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| 123 | ;
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| 124 | ASSUME DS:SV_DATA
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| 125 | SEEK PROC NEAR
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| 126 | PMIO_BEGIN
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| 127 | PUSH EAX
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| 128 | MOVZX EBX, BX
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| 129 | MOV AL, 0
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| 130 | MOV AH, 42H
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| 131 | INT 21H
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| 132 | POP EAX
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| 133 | PMIO_END
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| 134 | RET
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| 135 | SEEK ENDP
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| 136 |
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| 137 |
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| 138 | ;
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| 139 | ; In: BX File handle
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| 140 | ; ECX Number of bytes
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| 141 | ; AX:EDX Pointer to buffer
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| 142 | ;
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| 143 | ; Out: CY Error
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| 144 | ; NC NZ EOF
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| 145 | ; NC ZR OK
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| 146 | ;
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| 147 | ASSUME DS:SV_DATA
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| 148 | READ PROC NEAR
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| 149 | PMIO_BEGIN
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| 150 | PUSH EAX
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| 151 | PUSH DS
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| 152 | MOV DS, AX
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| 153 | ASSUME DS:NOTHING
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| 154 | MOVZX EBX, BX
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| 155 | MOV AH, 3FH
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| 156 | INT 21H
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| 157 | JC SHORT READ_RET
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| 158 | CMP ECX, EAX
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| 159 | CLC
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| 160 | READ_RET: POP DS
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| 161 | ASSUME DS:SV_DATA
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| 162 | POP EAX
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| 163 | PMIO_END
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| 164 | RET
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| 165 | READ ENDP
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| 166 |
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| 167 |
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| 168 | ;
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| 169 | ; In: BX File handle
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| 170 | ; ECX Number of bytes
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| 171 | ; AX:EDX Pointer to buffer
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| 172 | ;
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| 173 | ; Out: CY Error
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| 174 | ; NC NZ Disk full
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| 175 | ; NC ZR OK
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| 176 | ;
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| 177 | ASSUME DS:SV_DATA
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| 178 | WRITE PROC NEAR
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| 179 | PMIO_BEGIN
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| 180 | PUSH EAX
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| 181 | PUSH DS
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| 182 | MOV DS, AX
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| 183 | ASSUME DS:NOTHING
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| 184 | MOVZX EBX, BX
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| 185 | MOV AH, 40H
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| 186 | INT 21H
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| 187 | JC SHORT WRITE_RET
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| 188 | CMP ECX, EAX
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| 189 | CLC
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| 190 | WRITE_RET: POP DS
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| 191 | ASSUME DS:SV_DATA
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| 192 | POP EAX
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| 193 | PMIO_END
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| 194 | RET
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| 195 | WRITE ENDP
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| 196 |
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| 197 |
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| 198 | ;
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| 199 | ; Force stdout to refer to the CON device (put error message on screen)
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| 200 | ;
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| 201 | ASSUME DS:SV_DATA
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| 202 | FORCE_STDOUT PROC NEAR
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| 203 | PMIO_BEGIN
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| 204 | XOR EDX, EDX
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| 205 | LEA DX, STDOUT_NAME
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| 206 | MOV AH, 3DH
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| 207 | MOV AL, 41H ; Deny none; write
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| 208 | INT 21H
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| 209 | JC SHORT FS_RET
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| 210 | MOV EBX, EAX
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| 211 | MOV ECX, 1 ; stdout
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| 212 | MOV AH, 46H ; Force duplicate file handle
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| 213 | INT 21H
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| 214 | FS_RET: PMIO_END
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| 215 | RET
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| 216 | FORCE_STDOUT ENDP
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| 217 |
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| 218 |
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| 219 | ;
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| 220 | ; Find file in directories listed by an environment variable
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| 221 | ;
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| 222 | ; In: DS:SI File name
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| 223 | ; DS:BX Buffer (filled by FIND_FILE), must be large enough
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| 224 | ; ES:EDI Search path (separated by ';', 0 terminated)
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| 225 | ;
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| 226 | ; Out: CY Not found
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| 227 | ;
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| 228 | ; Note: ES:EDI must point to the value of the environment variable
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| 229 | ; The buffer pointed to by DS:BX will contain the path name on success
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| 230 | ; Blanks are not removed
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| 231 | ;
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| 232 | FIND_FILE PROC NEAR
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| 233 | PUSH EDI
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| 234 | PUSH CX
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| 235 | FF_NEXT_DIR:
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| 236 | ;
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| 237 | ; Now ES:DI points to the next directory
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| 238 | ; Build path name at DS:BX
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| 239 | ;
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| 240 | PUSH BX
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| 241 | PUSH SI
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| 242 | XOR CX, CX
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| 243 | FF_DIR_COPY: MOV AL, ES:[EDI]
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| 244 | OR AL, AL
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| 245 | JZ SHORT FF_DIR_END
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| 246 | CMP AL, ";"
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| 247 | JE SHORT FF_DIR_END
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| 248 | MOV [BX], AL
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| 249 | INC EDI
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| 250 | INC BX
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| 251 | INC CX
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| 252 | JMP SHORT FF_DIR_COPY
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| 253 | FF_DIR_END: JCXZ FF_EMPTY
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| 254 | MOV AL, [BX-1]
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| 255 | CMP AL, "\"
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| 256 | JE SHORT FF_FNAME_COPY
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| 257 | CMP AL, "/"
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| 258 | JE SHORT FF_FNAME_COPY
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| 259 | CMP AL, ":"
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| 260 | JE SHORT FF_FNAME_COPY
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| 261 | MOV BYTE PTR [BX], "\"
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| 262 | INC BX
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| 263 | FF_FNAME_COPY: MOV AL, [SI]
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| 264 | MOV [BX], AL
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| 265 | INC SI
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| 266 | INC BX
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| 267 | OR AL, AL
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| 268 | JNZ SHORT FF_FNAME_COPY
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| 269 | FF_EMPTY: POP SI
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| 270 | POP BX
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| 271 | JCXZ FF_SKIP_DIR
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| 272 | ;
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| 273 | ; Look for file
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| 274 | ;
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| 275 | PUSH EDX
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| 276 | MOVZX EDX, BX
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| 277 | CALL ACCESS
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| 278 | POP EDX
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| 279 | JNC SHORT FF_RET
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| 280 | ;
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| 281 | ; Try next directory
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| 282 | ;
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| 283 | FF_SKIP_DIR: CMP BYTE PTR ES:[EDI], 0
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| 284 | JE SHORT FF_FAILURE
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| 285 | INC EDI
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| 286 | JMP SHORT FF_NEXT_DIR
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| 287 |
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| 288 | FF_FAILURE: MOV BYTE PTR [BX], 0
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| 289 | STC
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| 290 | FF_RET: POP CX
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| 291 | POP EDI
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| 292 | RET
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| 293 | FIND_FILE ENDP
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| 294 |
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| 295 |
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| 296 |
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| 297 | ;
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| 298 | ; In: DS:EDX Name
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| 299 | ;
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| 300 | ; Out: CY Not found or not a file
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| 301 | ;
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| 302 | ACCESS PROC NEAR
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| 303 | PUSH AX
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| 304 | PUSH CX
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| 305 | MOV AH, 43H ; Get/set file attributes
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| 306 | MOV AL, 00H ; Get file attributes
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| 307 | INT 21H
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| 308 | JC SHORT ACCESS_RET
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| 309 | TEST CX, 18H ; Volume label, directory?
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| 310 | JZ SHORT ACCESS_RET
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| 311 | STC
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| 312 | ACCESS_RET: POP CX
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| 313 | POP AX
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| 314 | RET
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| 315 | ACCESS ENDP
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| 316 |
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| 317 |
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| 318 | SV_CODE ENDS
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| 319 |
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| 320 | END
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