[150] | 1 | ; Project name : XTIDE Universal BIOS |
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[3] | 2 | ; Description : Functions for finding Disk Parameter Table. |
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| 3 | |
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| 4 | ; Section containing code |
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| 5 | SECTION .text |
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| 6 | |
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| 7 | ;-------------------------------------------------------------------- |
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[262] | 8 | ; Checks if drive is handled by this BIOS, and return DPT pointer. |
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[3] | 9 | ; |
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[294] | 10 | ; FindDPT_ForDriveNumberInDL |
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[3] | 11 | ; Parameters: |
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[262] | 12 | ; DL: Drive number |
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[3] | 13 | ; DS: RAMVARS segment |
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| 14 | ; Returns: |
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[262] | 15 | ; CF: Cleared if drive is handled by this BIOS |
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| 16 | ; Set if drive belongs to some other BIOS |
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| 17 | ; DI: DPT Pointer if drive is handled by this BIOS |
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| 18 | ; Zero if drive belongs to some other BIOS |
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[3] | 19 | ; Corrupts registers: |
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[262] | 20 | ; Nothing |
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[150] | 21 | ;-------------------------------------------------------------------- |
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| 22 | ALIGN JUMP_ALIGN |
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[294] | 23 | FindDPT_ForDriveNumberInDL: |
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[262] | 24 | xchg di, ax ; Save the contents of AX in DI |
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| 25 | |
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[294] | 26 | ; |
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[262] | 27 | ; Check Our Hard Disks |
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| 28 | ; |
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| 29 | mov ax, [RAMVARS.wDrvCntAndFirst] ; Drive count to AH, First number to AL |
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| 30 | add ah, al ; One past last drive to AH |
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| 31 | |
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[258] | 32 | %ifdef MODULE_SERIAL_FLOPPY |
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[262] | 33 | cmp dl, ah ; Above last supported? |
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| 34 | jae SHORT .HardDiskNotHandledByThisBIOS |
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[294] | 35 | |
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[262] | 36 | cmp dl, al ; Below first supported? |
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| 37 | jae SHORT .CalcDPTForDriveNumber |
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| 38 | |
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[294] | 39 | ALIGN JUMP_ALIGN |
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| 40 | .HardDiskNotHandledByThisBIOS: |
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[262] | 41 | ; |
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| 42 | ; Check Our Floppy Disks |
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[294] | 43 | ; |
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[262] | 44 | call RamVars_UnpackFlopCntAndFirstToAL |
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| 45 | js SHORT .DiskIsNotHandledByThisBIOS |
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[294] | 46 | |
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[277] | 47 | cbw ; Always 0h (no floppy drive covered above) |
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| 48 | adc ah, al ; Add in first drive number and number of drives |
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| 49 | |
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[262] | 50 | cmp ah, dl ; Check second drive if two, first drive if only one |
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| 51 | jz SHORT .CalcDPTForDriveNumber |
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| 52 | cmp al, dl ; Check first drive in all cases, redundant but OK to repeat |
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[294] | 53 | jnz SHORT .DiskIsNotHandledByThisBIOS |
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[262] | 54 | %else |
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[294] | 55 | cmp dl, ah ; Above last supported? |
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[262] | 56 | jae SHORT .DiskIsNotHandledByThisBIOS |
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[294] | 57 | |
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[262] | 58 | cmp dl, al ; Below first supported? |
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[294] | 59 | jb SHORT .DiskIsNotHandledByThisBIOS |
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[258] | 60 | %endif |
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[262] | 61 | ; fall-through to CalcDPTForDriveNumber |
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[150] | 62 | |
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| 63 | ;-------------------------------------------------------------------- |
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| 64 | ; Finds Disk Parameter Table for drive number. |
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[294] | 65 | ; Not intended to be called except by FindDPT_ForDriveNumberInDL |
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[150] | 66 | ; |
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[262] | 67 | ; CalcDPTForDriveNumber |
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[150] | 68 | ; Parameters: |
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| 69 | ; DL: Drive number |
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| 70 | ; DS: RAMVARS segment |
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[294] | 71 | ; DI: Saved copy of AX from entry at FindDPT_ForDriveNumberInDL |
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[150] | 72 | ; Returns: |
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| 73 | ; DS:DI: Ptr to DPT |
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[262] | 74 | ; CF: Clear |
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[150] | 75 | ; Corrupts registers: |
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[3] | 76 | ; Nothing |
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| 77 | ;-------------------------------------------------------------------- |
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| 78 | ALIGN JUMP_ALIGN |
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[262] | 79 | .CalcDPTForDriveNumber: |
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[150] | 80 | push dx |
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[3] | 81 | |
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[258] | 82 | %ifdef MODULE_SERIAL_FLOPPY |
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| 83 | mov ax, [RAMVARS.wDrvCntAndFirst] |
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[294] | 84 | |
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[258] | 85 | test dl, dl |
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| 86 | js .harddisk |
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| 87 | |
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| 88 | call RamVars_UnpackFlopCntAndFirstToAL |
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| 89 | add dl, ah ; add in end of hard disk DPT list, floppies start immediately after |
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[294] | 90 | |
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| 91 | ALIGN JUMP_ALIGN |
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[258] | 92 | .harddisk: |
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| 93 | sub dl, al ; subtract off beginning of either hard disk or floppy list (as appropriate) |
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| 94 | %else |
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| 95 | sub dl, [RAMVARS.bFirstDrv] ; subtract off beginning of hard disk list |
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| 96 | %endif |
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[262] | 97 | |
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[294] | 98 | .CalcDPTForNewDrive: |
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[150] | 99 | mov al, LARGEST_DPT_SIZE |
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[294] | 100 | |
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[150] | 101 | mul dl |
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[294] | 102 | add ax, BYTE RAMVARS_size ; Clears CF (will not overflow) |
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[3] | 103 | |
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[150] | 104 | pop dx |
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[262] | 105 | |
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| 106 | xchg di, ax ; Restore AX from entry at FindDPT_ForDriveNumber, put DPT pointer in DI |
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[150] | 107 | ret |
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| 108 | |
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[294] | 109 | ALIGN JUMP_ALIGN |
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| 110 | .DiskIsNotHandledByThisBIOS: |
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[259] | 111 | ; |
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[262] | 112 | ; Drive not found... |
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| 113 | ; |
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| 114 | xor ax, ax ; Clear DPT pointer |
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[294] | 115 | stc ; Is not supported by our BIOS |
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| 116 | |
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[262] | 117 | xchg di, ax ; Restore AX from save at top |
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[259] | 118 | ret |
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| 119 | |
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[271] | 120 | |
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[259] | 121 | ;-------------------------------------------------------------------- |
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[271] | 122 | ; FindDPT_ForIdevarsOffsetInDL |
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| 123 | ; Parameters: |
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| 124 | ; DL: Offset to IDEVARS to search for |
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| 125 | ; DS: RAMVARS segment |
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| 126 | ; Returns: |
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| 127 | ; DS:DI: Ptr to first DPT with same IDEVARS as in DL |
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| 128 | ; CF: Clear if wanted DPT found |
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| 129 | ; Set if DPT not found, or no DPTs present |
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| 130 | ; Corrupts registers: |
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| 131 | ; SI |
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| 132 | ;-------------------------------------------------------------------- |
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| 133 | FindDPT_ForIdevarsOffsetInDL: |
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| 134 | mov si, IterateFindFirstDPTforIdevars ; iteration routine (see below) |
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| 135 | jmp SHORT FindDPT_IterateAllDPTs ; look for the first drive on this controller, if any |
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| 136 | |
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| 137 | ;-------------------------------------------------------------------- |
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[294] | 138 | ; Iteration routine for FindDPT_ForIdevarsOffsetInDL, |
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[271] | 139 | ; for use with IterateAllDPTs |
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[294] | 140 | ; |
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[271] | 141 | ; Returns when DPT is found on the controller with Idevars offset in DL |
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| 142 | ; |
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| 143 | ; IterateFindFirstDPTforIdevars |
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| 144 | ; DL: Offset to IDEVARS to search from DPTs |
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| 145 | ; DS:DI: Ptr to DPT to examine |
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| 146 | ; Returns: |
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| 147 | ; CF: Clear if wanted DPT found |
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| 148 | ; Set if wrong DPT |
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| 149 | ;-------------------------------------------------------------------- |
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[294] | 150 | IterateFindFirstDPTforIdevars: |
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[271] | 151 | cmp dl, [di+DPT.bIdevarsOffset] ; Clears CF if matched |
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| 152 | je .done |
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| 153 | stc ; Set CF for not found |
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[294] | 154 | .done: |
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[271] | 155 | ret |
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| 156 | |
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| 157 | |
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| 158 | ;-------------------------------------------------------------------- |
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[262] | 159 | ; Finds pointer to first unused Disk Parameter Table. |
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| 160 | ; Should only be used before DetectDrives is complete (not valid after this time). |
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[3] | 161 | ; |
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[262] | 162 | ; FindDPT_ForNewDriveToDSDI |
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[3] | 163 | ; Parameters: |
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| 164 | ; DS: RAMVARS segment |
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| 165 | ; Returns: |
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[262] | 166 | ; DS:DI: Ptr to first unused DPT |
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[3] | 167 | ; Corrupts registers: |
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[262] | 168 | ; AX |
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[3] | 169 | ;-------------------------------------------------------------------- |
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[262] | 170 | ALIGN JUMP_ALIGN |
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| 171 | FindDPT_ForNewDriveToDSDI: |
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| 172 | push dx |
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[294] | 173 | |
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[262] | 174 | %ifdef MODULE_SERIAL_FLOPPY |
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| 175 | mov dx, [RAMVARS.wDrvCntAndFlopCnt] |
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| 176 | add dl, dh |
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| 177 | %else |
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| 178 | mov dl, [RAMVARS.bDrvCnt] |
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| 179 | %endif |
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[294] | 180 | |
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[262] | 181 | jmp short FindDPT_ForDriveNumberInDL.CalcDPTForNewDrive |
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[3] | 182 | |
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[152] | 183 | ;-------------------------------------------------------------------- |
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[233] | 184 | ; IterateToDptWithFlagsHighInBL |
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[152] | 185 | ; Parameters: |
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| 186 | ; DS:DI: Ptr to DPT to examine |
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[294] | 187 | ; BL: Bit(s) to test in DPT.bFlagsHigh |
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[152] | 188 | ; Returns: |
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[262] | 189 | ; CF: Clear if wanted DPT found |
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| 190 | ; Set if wrong DPT |
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[152] | 191 | ; Corrupts registers: |
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| 192 | ; Nothing |
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| 193 | ;-------------------------------------------------------------------- |
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| 194 | ALIGN JUMP_ALIGN |
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[294] | 195 | IterateToDptWithFlagsHighInBL: |
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| 196 | test [di+DPT.bFlagsHigh], bl ; Clears CF |
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[262] | 197 | jnz SHORT .ReturnRightDPT |
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| 198 | stc |
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[294] | 199 | .ReturnRightDPT: |
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[3] | 200 | ret |
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| 201 | |
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| 202 | ;-------------------------------------------------------------------- |
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[233] | 203 | ; FindDPT_ToDSDIforSerialDevice |
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[161] | 204 | ; Parameters: |
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| 205 | ; DS: RAMVARS segment |
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| 206 | ; Returns: |
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| 207 | ; DS:DI: Ptr to DPT |
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| 208 | ; CF: Set if wanted DPT found |
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| 209 | ; Cleared if DPT not found |
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| 210 | ; Corrupts registers: |
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[203] | 211 | ; SI |
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[161] | 212 | ;-------------------------------------------------------------------- |
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[265] | 213 | %ifdef MODULE_SERIAL |
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[294] | 214 | ALIGN JUMP_ALIGN |
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| 215 | FindDPT_ToDSDIforSerialDevice: |
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[233] | 216 | mov bl, FLGH_DPT_SERIAL_DEVICE |
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| 217 | ; fall-through |
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[265] | 218 | %endif |
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[294] | 219 | |
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[233] | 220 | ;-------------------------------------------------------------------- |
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| 221 | ; FindDPT_ToDSDIforFlagsHigh |
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| 222 | ; Parameters: |
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| 223 | ; DS: RAMVARS segment |
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| 224 | ; BL: Bit(s) to test in DPT.bFlagsHigh |
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| 225 | ; Returns: |
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| 226 | ; DS:DI: Ptr to DPT |
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| 227 | ; CF: Set if wanted DPT found |
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| 228 | ; Cleared if DPT not found |
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| 229 | ; Corrupts registers: |
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| 230 | ; SI |
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| 231 | ;-------------------------------------------------------------------- |
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[161] | 232 | ALIGN JUMP_ALIGN |
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[294] | 233 | FindDPT_ToDSDIforFlagsHighInBL: |
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[233] | 234 | mov si, IterateToDptWithFlagsHighInBL |
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[161] | 235 | ; Fall to IterateAllDPTs |
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| 236 | |
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| 237 | ;-------------------------------------------------------------------- |
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[3] | 238 | ; Iterates all Disk Parameter Tables. |
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| 239 | ; |
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[271] | 240 | ; FindDPT_IterateAllDPTs |
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[3] | 241 | ; Parameters: |
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[152] | 242 | ; AX,BX,DX: Parameters to callback function |
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| 243 | ; CS:SI: Ptr to callback function |
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[262] | 244 | ; Callback routine should return CF=clear if found |
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[152] | 245 | ; DS: RAMVARS segment |
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[3] | 246 | ; Returns: |
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[152] | 247 | ; DS:DI: Ptr to wanted DPT (if found) |
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[258] | 248 | ; If not found, points to first empty DPT |
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[262] | 249 | ; CF: Clear if wanted DPT found |
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| 250 | ; Set if DPT not found, or no DPTs present |
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[3] | 251 | ; Corrupts registers: |
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[150] | 252 | ; Nothing unless corrupted by callback function |
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[3] | 253 | ;-------------------------------------------------------------------- |
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| 254 | ALIGN JUMP_ALIGN |
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[271] | 255 | FindDPT_IterateAllDPTs: |
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[3] | 256 | push cx |
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[258] | 257 | |
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| 258 | mov di, RAMVARS_size ; Point DS:DI to first DPT |
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[294] | 259 | eMOVZX cx, [RAMVARS.bDrvCnt] |
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[262] | 260 | jcxz .NotFound ; Return if no drives |
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[294] | 261 | |
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[3] | 262 | ALIGN JUMP_ALIGN |
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| 263 | .LoopWhileDPTsLeft: |
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| 264 | call si ; Is wanted DPT? |
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[262] | 265 | jnc SHORT .Found ; If so, return |
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| 266 | add di, BYTE LARGEST_DPT_SIZE ; Point to next DPT |
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[258] | 267 | loop .LoopWhileDPTsLeft |
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[262] | 268 | |
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[3] | 269 | ALIGN JUMP_ALIGN |
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[262] | 270 | .NotFound: |
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| 271 | stc |
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| 272 | |
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| 273 | ALIGN JUMP_ALIGN |
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| 274 | .Found: |
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[3] | 275 | pop cx |
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| 276 | ret |
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[259] | 277 | |
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