[99] | 1 | ; Project name : XTIDE Universal BIOS
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[3] | 2 | ; Description : Functions for accessing DPT data.
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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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[364] | 7 | %ifdef MODULE_ADVANCED_ATA
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[3] | 8 | ;--------------------------------------------------------------------
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[364] | 9 | ; AccessDPT_GetIdeBasePortToBX
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| 10 | ; Parameters:
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| 11 | ; DS:DI: Ptr to Disk Parameter Table
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| 12 | ; Returns:
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| 13 | ; BX: IDE Base Port Address
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| 14 | ; Corrupts registers:
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| 15 | ; Nothing
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| 16 | ;--------------------------------------------------------------------
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| 17 | ALIGN JUMP_ALIGN
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| 18 | AccessDPT_GetIdeBasePortToBX:
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| 19 | eMOVZX bx, [di+DPT.bIdevarsOffset] ; CS:BX points to IDEVARS
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| 20 | mov bx, [cs:bx+IDEVARS.wPort]
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| 21 | ret
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| 22 |
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| 23 | %endif
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| 24 |
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| 25 |
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| 26 | ;--------------------------------------------------------------------
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[150] | 27 | ; AccessDPT_GetDriveSelectByteToAL
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| 28 | ; Parameters:
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| 29 | ; DS:DI: Ptr to Disk Parameter Table
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| 30 | ; Returns:
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| 31 | ; AL: Drive Select Byte
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| 32 | ; Corrupts registers:
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| 33 | ; Nothing
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| 34 | ;--------------------------------------------------------------------
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| 35 | ALIGN JUMP_ALIGN
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| 36 | AccessDPT_GetDriveSelectByteToAL:
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| 37 | mov al, [di+DPT.wFlags]
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| 38 | and al, FLG_DRVNHEAD_LBA | FLG_DRVNHEAD_DRV
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| 39 | or al, MASK_DRVNHEAD_SET ; Bits set to 1 for old drives
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| 40 | ret
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| 41 |
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| 42 |
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| 43 | ;--------------------------------------------------------------------
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| 44 | ; AccessDPT_GetDeviceControlByteToAL
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| 45 | ; Parameters:
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| 46 | ; DS:DI: Ptr to Disk Parameter Table
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| 47 | ; Returns:
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| 48 | ; AL: Device Control Byte
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| 49 | ; Corrupts registers:
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| 50 | ; Nothing
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| 51 | ;--------------------------------------------------------------------
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| 52 | ALIGN JUMP_ALIGN
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| 53 | AccessDPT_GetDeviceControlByteToAL:
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| 54 | xor al, al
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[158] | 55 | test BYTE [di+DPT.bFlagsLow], FLGL_DPT_ENABLE_IRQ
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[150] | 56 | jnz SHORT .EnableDeviceIrq
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| 57 | or al, FLG_DEVCONTROL_nIEN ; Disable IRQ
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| 58 | .EnableDeviceIrq:
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| 59 | ret
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| 60 |
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[227] | 61 |
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[150] | 62 | ;--------------------------------------------------------------------
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[227] | 63 | ; AccessDPT_GetLCHStoAXBLBH
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[3] | 64 | ; Parameters:
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| 65 | ; DS:DI: Ptr to Disk Parameter Table
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| 66 | ; Returns:
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[227] | 67 | ; AX: Number of L-CHS cylinders
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| 68 | ; BL: Number of L-CHS heads
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| 69 | ; BH: Number of L-CHS sectors per track
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[3] | 70 | ; Corrupts registers:
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[227] | 71 | ; CX, DX
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[3] | 72 | ;--------------------------------------------------------------------
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[227] | 73 | AccessDPT_GetLCHStoAXBLBH:
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| 74 | ; Return LBA-assisted CHS if LBA addressing used
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[173] | 75 | test BYTE [di+DPT.bFlagsLow], FLG_DRVNHEAD_LBA
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[227] | 76 | jz SHORT .ConvertPchsToLchs
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[173] | 77 |
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[227] | 78 | call AccessDPT_GetLbaSectorCountToBXDXAX
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[358] | 79 | call LbaAssist_ConvertSectorCountFromBXDXAXtoLbaAssistedCHSinDXAXBLBH
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| 80 | LIMIT_LBA_CYLINDERS_IN_DXAX_TO_LCHS_CYLINDERS
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[227] | 81 | ret
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[173] | 82 |
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[227] | 83 | .ConvertPchsToLchs:
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| 84 | mov ax, [di+DPT.wPchsCylinders]
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| 85 | mov bx, [di+DPT.wPchsHeadsAndSectors]
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[230] | 86 | ; Fall to AccessDPT_ShiftPCHinAXBLtoLCH
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[227] | 87 |
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| 88 |
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| 89 | ;--------------------------------------------------------------------
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| 90 | ; AccessDPT_ShiftPCHinAXBLtoLCH
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[173] | 91 | ; Parameters:
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[227] | 92 | ; AX: P-CHS cylinders (1...16383)
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| 93 | ; BL: P-CHS heads (1...16)
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[173] | 94 | ; Returns:
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[227] | 95 | ; AX: Number of L-CHS cylinders (1...1024)
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| 96 | ; BL: Number of L-CHS heads (1...255)
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[230] | 97 | ; CX: Number of bits shifted (4 at most)
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[173] | 98 | ; Corrupts registers:
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| 99 | ; Nothing
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| 100 | ;--------------------------------------------------------------------
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[227] | 101 | AccessDPT_ShiftPCHinAXBLtoLCH:
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[173] | 102 | xor cx, cx
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| 103 | .ShiftLoop:
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[227] | 104 | cmp ax, MAX_LCHS_CYLINDERS ; Need to shift?
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[231] | 105 | jbe SHORT .Return ; If not, return
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[173] | 106 | inc cx ; Increment shift count
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[227] | 107 | shr ax, 1 ; Halve cylinders
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| 108 | shl bl, 1 ; Double heads
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[231] | 109 | jnz SHORT .ShiftLoop ; Falls through only on the last (4th) iteration and only if BL was 16 on entry
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| 110 | dec bl ; DOS doesn't support drives with 256 heads so we limit heads to 255
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| 111 | ; We can save a byte here by using DEC BX if we don't care about BH
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| 112 | .Return:
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[173] | 113 | ret
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| 114 |
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[227] | 115 |
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[173] | 116 | ;--------------------------------------------------------------------
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[230] | 117 | ; AccessDPT_GetLbaSectorCountToBXDXAX
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| 118 | ; Parameters:
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| 119 | ; DS:DI: Ptr to Disk Parameter Table
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| 120 | ; Returns:
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| 121 | ; BX:DX:AX: 48-bit sector count
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| 122 | ; Corrupts registers:
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| 123 | ; Nothing
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| 124 | ;--------------------------------------------------------------------
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| 125 | AccessDPT_GetLbaSectorCountToBXDXAX:
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| 126 | mov ax, [di+DPT.twLbaSectors]
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| 127 | mov dx, [di+DPT.twLbaSectors+2]
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| 128 | mov bx, [di+DPT.twLbaSectors+4]
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| 129 | ret
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| 130 |
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| 131 |
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| 132 | ;--------------------------------------------------------------------
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[3] | 133 | ; Returns pointer to DRVPARAMS for master or slave drive.
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| 134 | ;
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| 135 | ; AccessDPT_GetPointerToDRVPARAMStoCSBX
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| 136 | ; Parameters:
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| 137 | ; DS:DI: Ptr to Disk Parameter Table
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| 138 | ; Returns:
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| 139 | ; CS:BX: Ptr to DRVPARAMS
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| 140 | ; Corrupts registers:
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| 141 | ; Nothing
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| 142 | ;--------------------------------------------------------------------
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| 143 | ALIGN JUMP_ALIGN
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| 144 | AccessDPT_GetPointerToDRVPARAMStoCSBX:
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[150] | 145 | eMOVZX bx, [di+DPT.bIdevarsOffset] ; CS:BX points to IDEVARS
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| 146 | add bx, BYTE IDEVARS.drvParamsMaster ; CS:BX points to Master Drive DRVPARAMS
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[158] | 147 | test BYTE [di+DPT.bFlagsLow], FLGL_DPT_SLAVE
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[150] | 148 | jz SHORT .ReturnPointerToDRVPARAMS
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| 149 | add bx, BYTE DRVPARAMS_size ; CS:BX points to Slave Drive DRVPARAMS
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| 150 | .ReturnPointerToDRVPARAMS:
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[3] | 151 | ret
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[200] | 152 |
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| 153 | ;--------------------------------------------------------------------
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| 154 | ; AccessDPT_GetUnshiftedAddressModeToALZF
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| 155 | ; Parameters:
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| 156 | ; DS:DI: Ptr to Disk Parameter Table
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| 157 | ; Returns:
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[230] | 158 | ; AL: Addressing Mode (L-CHS, P-CHS, LBA28, LBA48)
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[200] | 159 | ; unshifted (still shifted where it is in bFlagsLow)
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| 160 | ; ZF: Set based on value in AL
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| 161 | ; Corrupts registers:
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| 162 | ; AL
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| 163 | ;--------------------------------------------------------------------
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[230] | 164 | ;
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| 165 | ; Converted to a macro since only called in two places, and the call/ret overhead
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[200] | 166 | ; is not worth it for these two instructions (4 bytes total)
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| 167 | ;
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| 168 | %macro AccessDPT_GetUnshiftedAddressModeToALZF 0
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| 169 | mov al, [di+DPT.bFlagsLow]
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| 170 | and al, MASKL_DPT_ADDRESSING_MODE
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| 171 | %endmacro
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