[150] | 1 | ; Project name : XTIDE Universal BIOS |
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[3] | 2 | ; Description : Functions for address translations. |
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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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[150] | 7 | ; Jump table for conversion functions |
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| 8 | ALIGN WORD_ALIGN |
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| 9 | g_rgfnAddressTranslation: |
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| 10 | dw DoNotConvertLCHS ; 0, ADDR_DPT_LCHS |
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| 11 | dw ConvertLCHStoPCHS ; 1, ADDR_DPT_PCHS |
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| 12 | dw ConvertLCHStoLBARegisterValues ; 2, ADDR_DPT_LBA28 |
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| 13 | dw ConvertLCHStoLBARegisterValues ; 3, ADDR_DPT_LBA48 |
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| 14 | |
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| 15 | |
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[3] | 16 | ;-------------------------------------------------------------------- |
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[150] | 17 | ; HAddress_OldInt13hAddressToIdeAddress |
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[3] | 18 | ; Parameters: |
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| 19 | ; CH: Cylinder number, bits 7...0 |
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| 20 | ; CL: Bits 7...6: Cylinder number bits 9 and 8 |
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| 21 | ; Bits 5...0: Starting sector number (1...63) |
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| 22 | ; DH: Starting head number (0...255) |
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| 23 | ; DS:DI: Ptr to DPT |
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| 24 | ; Returns: |
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| 25 | ; BL: LBA Low Register / Sector Number Register (LBA 7...0) |
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| 26 | ; CL: LBA Mid Register / Low Cylinder Register (LBA 15...8) |
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| 27 | ; CH: LBA High Register / High Cylinder Register (LBA 23...16) |
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| 28 | ; BH: Drive and Head Register (LBA 27...24) |
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| 29 | ; Corrupts registers: |
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| 30 | ; AX, DX |
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| 31 | ;-------------------------------------------------------------------- |
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| 32 | ALIGN JUMP_ALIGN |
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[150] | 33 | HAddress_OldInt13hAddressToIdeAddress: |
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| 34 | call AccessDPT_GetAddressingModeForWordLookToBX |
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[3] | 35 | push WORD [cs:bx+g_rgfnAddressTranslation] ; Push return address |
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[150] | 36 | ; Fall to HAddress_ExtractLCHSparametersFromOldInt13hAddress |
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[3] | 37 | |
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| 38 | ;--------------------------------------------------------------------- |
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[150] | 39 | ; HAddress_ExtractLCHSparametersFromOldInt13hAddress |
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[3] | 40 | ; Parameters: |
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| 41 | ; CH: Cylinder number, bits 7...0 |
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| 42 | ; CL: Bits 7...6: Cylinder number bits 9 and 8 |
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| 43 | ; Bits 5...0: Sector number |
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| 44 | ; DH: Head number |
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| 45 | ; Returns: |
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| 46 | ; BL: Sector number (1...63) |
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| 47 | ; BH: Head number (0...255) |
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| 48 | ; CX: Cylinder number (0...1023) |
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| 49 | ; Corrupts registers: |
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| 50 | ; Nothing |
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| 51 | ;-------------------------------------------------------------------- |
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[150] | 52 | HAddress_ExtractLCHSparametersFromOldInt13hAddress: |
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[3] | 53 | mov bl, cl ; Copy sector number... |
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| 54 | and bl, 3Fh ; ...and limit to 1...63 |
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| 55 | sub cl, bl ; Remove from cylinder number high |
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| 56 | eROL_IM cl, 2 ; High bits to beginning |
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| 57 | mov bh, dh ; Copy Head number |
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| 58 | xchg cl, ch ; Cylinder number now in CX |
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| 59 | ret |
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| 60 | |
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| 61 | |
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| 62 | ;--------------------------------------------------------------------- |
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[150] | 63 | ; Converts LCHS parameters to IDE P-CHS parameters. |
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[3] | 64 | ; PCylinder = (LCylinder << n) + (LHead / PHeadCount) |
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| 65 | ; PHead = LHead % PHeadCount |
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| 66 | ; PSector = LSector |
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| 67 | ; |
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| 68 | ; HAddress_ConvertLCHStoPCHS: |
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| 69 | ; Parameters: |
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| 70 | ; BL: Sector number (1...63) |
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| 71 | ; BH: Head number (0...255) |
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| 72 | ; CX: Cylinder number (0...1023) |
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| 73 | ; DS:DI: Ptr to Disk Parameter Table |
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| 74 | ; Returns: |
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| 75 | ; BL: Sector number (1...63) |
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| 76 | ; BH: Head number (0...15) |
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| 77 | ; CX: Cylinder number (0...16382) |
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| 78 | ; Corrupts registers: |
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| 79 | ; AX, DX |
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| 80 | ;-------------------------------------------------------------------- |
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| 81 | ALIGN JUMP_ALIGN |
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[150] | 82 | ConvertLCHStoPCHS: |
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[3] | 83 | ; LHead / PHeadCount and LHead % PHeadCount |
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| 84 | eMOVZX ax, bh ; Copy L-CHS Head number to AX |
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[150] | 85 | div BYTE [di+DPT.bPchsHeads]; AL = LHead / PHeadCount, AH = LHead % PHeadCount |
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[3] | 86 | mov bh, ah ; Copy P-CHS Head number to BH |
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| 87 | xor ah, ah ; AX = LHead / PHeadCount |
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| 88 | |
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| 89 | ; (LCylinder << n) + (LHead / PHeadCount) |
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| 90 | mov dx, cx ; Copy L-CHS Cylinder number to DX |
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[150] | 91 | mov cl, [di+DPT.wFlags] ; Load shift count |
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| 92 | and cl, MASK_DPT_CHS_SHIFT_COUNT |
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[3] | 93 | shl dx, cl ; DX = LCylinder << n |
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| 94 | add ax, dx ; AX = P-CHS Cylinder number |
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| 95 | mov cx, ax ; Copy P-CHS Cylinder number to CX |
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[150] | 96 | DoNotConvertLCHS: |
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[3] | 97 | ret |
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| 98 | |
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| 99 | |
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| 100 | ;--------------------------------------------------------------------- |
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| 101 | ; Converts LCHS parameters to 28-bit LBA address. |
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[150] | 102 | ; Only 24-bits are used since LHCS to LBA28 conversion has 8.4GB limit. |
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| 103 | ; LBA = ((cylToSeek*headsPerCyl+headToSeek)*sectPerTrack)+sectToSeek-1 |
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| 104 | ; |
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[3] | 105 | ; Returned address is in same registers that |
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| 106 | ; HAddress_DoNotConvertLCHS and HAddress_ConvertLCHStoPCHS returns. |
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| 107 | ; |
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[150] | 108 | ; ConvertLCHStoLBARegisterValues: |
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[3] | 109 | ; Parameters: |
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| 110 | ; BL: Sector number (1...63) |
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| 111 | ; BH: Head number (0...255) |
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| 112 | ; CX: Cylinder number (0...1023) |
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| 113 | ; DS:DI: Ptr to Disk Parameter Table |
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| 114 | ; Returns: |
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| 115 | ; BL: LBA Low Register / Sector Number Register (LBA 7...0) |
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| 116 | ; CL: LBA Mid Register / Low Cylinder Register (LBA 15...8) |
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| 117 | ; CH: LBA High Register / High Cylinder Register (LBA 23...16) |
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| 118 | ; BH: Drive and Head Register (LBA 27...24) |
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| 119 | ; Corrupts registers: |
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| 120 | ; AX, DX |
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| 121 | ;-------------------------------------------------------------------- |
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| 122 | ALIGN JUMP_ALIGN |
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[150] | 123 | ConvertLCHStoLBARegisterValues: |
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[3] | 124 | ; cylToSeek*headsPerCyl (18-bit result) |
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| 125 | mov ax, cx ; Copy Cylinder number to AX |
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[150] | 126 | eMOVZX dx, BYTE [di+DPT.bLchsHeads] |
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| 127 | mul dx ; DX:AX = cylToSeek*headsPerCyl |
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[3] | 128 | |
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| 129 | ; +=headToSeek (18-bit result) |
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| 130 | add al, bh ; Add Head number to DX:AX |
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| 131 | adc ah, dh ; DH = Zero after previous multiplication |
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| 132 | adc dl, dh |
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| 133 | |
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| 134 | ; *=sectPerTrack (18-bit by 6-bit multiplication with 24-bit result) |
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[150] | 135 | eMOVZX cx, BYTE [di+DPT.bPchsSectors] ; Load Sectors per Track |
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[3] | 136 | xchg ax, dx ; Hiword to AX, loword to DX |
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| 137 | mul cl ; AX = hiword * Sectors per Track |
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| 138 | mov bh, al ; Backup hiword * Sectors per Track |
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| 139 | xchg ax, dx ; Loword back to AX |
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| 140 | mul cx ; DX:AX = loword * Sectors per Track |
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| 141 | add dl, bh ; DX:AX = (cylToSeek*headsPerCyl+headToSeek)*sectPerTrack |
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| 142 | |
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| 143 | ; +=sectToSeek-1 (24-bit result) |
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| 144 | xor bh, bh ; Sector number now in BX |
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| 145 | dec bx ; sectToSeek-=1 |
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| 146 | add ax, bx ; Add to loword |
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| 147 | adc dl, bh ; Add possible carry to byte2, BH=zero |
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[150] | 148 | |
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| 149 | ; Copy DX:AX to proper return registers |
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| 150 | xchg bx, ax ; BL = Sector Number Register (LBA 7...0) |
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| 151 | mov cl, bh ; Low Cylinder Register (LBA 15...8) |
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| 152 | mov ch, dl ; High Cylinder Register (LBA 23...16) |
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| 153 | mov bh, dh ; Drive and Head Register (LBA 27...24) |
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[3] | 154 | ret |
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