| [99] | 1 | ; Project name : XTIDE Universal BIOS
|
|---|
| [3] | 2 | ; Description : Functions for accessing DPT data.
|
|---|
| 3 |
|
|---|
| 4 | ; Section containing code
|
|---|
| 5 | SECTION .text
|
|---|
| 6 |
|
|---|
| 7 | ;--------------------------------------------------------------------
|
|---|
| [150] | 8 | ; AccessDPT_GetDriveSelectByteToAL
|
|---|
| 9 | ; Parameters:
|
|---|
| 10 | ; DS:DI: Ptr to Disk Parameter Table
|
|---|
| 11 | ; Returns:
|
|---|
| 12 | ; AL: Drive Select Byte
|
|---|
| 13 | ; Corrupts registers:
|
|---|
| 14 | ; Nothing
|
|---|
| 15 | ;--------------------------------------------------------------------
|
|---|
| 16 | ALIGN JUMP_ALIGN
|
|---|
| 17 | AccessDPT_GetDriveSelectByteToAL:
|
|---|
| 18 | mov al, [di+DPT.wFlags]
|
|---|
| 19 | and al, FLG_DRVNHEAD_LBA | FLG_DRVNHEAD_DRV
|
|---|
| 20 | or al, MASK_DRVNHEAD_SET ; Bits set to 1 for old drives
|
|---|
| 21 | ret
|
|---|
| 22 |
|
|---|
| 23 |
|
|---|
| 24 | ;--------------------------------------------------------------------
|
|---|
| 25 | ; AccessDPT_GetDeviceControlByteToAL
|
|---|
| 26 | ; Parameters:
|
|---|
| 27 | ; DS:DI: Ptr to Disk Parameter Table
|
|---|
| 28 | ; Returns:
|
|---|
| 29 | ; AL: Device Control Byte
|
|---|
| 30 | ; Corrupts registers:
|
|---|
| 31 | ; Nothing
|
|---|
| 32 | ;--------------------------------------------------------------------
|
|---|
| 33 | ALIGN JUMP_ALIGN
|
|---|
| 34 | AccessDPT_GetDeviceControlByteToAL:
|
|---|
| 35 | xor al, al
|
|---|
| [158] | 36 | test BYTE [di+DPT.bFlagsLow], FLGL_DPT_ENABLE_IRQ
|
|---|
| [150] | 37 | jnz SHORT .EnableDeviceIrq
|
|---|
| 38 | or al, FLG_DEVCONTROL_nIEN ; Disable IRQ
|
|---|
| 39 | .EnableDeviceIrq:
|
|---|
| 40 | ret
|
|---|
| 41 |
|
|---|
| [227] | 42 |
|
|---|
| [150] | 43 | ;--------------------------------------------------------------------
|
|---|
| [227] | 44 | ; AccessDPT_GetLCHStoAXBLBH
|
|---|
| [3] | 45 | ; Parameters:
|
|---|
| 46 | ; DS:DI: Ptr to Disk Parameter Table
|
|---|
| 47 | ; Returns:
|
|---|
| [227] | 48 | ; AX: Number of L-CHS cylinders
|
|---|
| 49 | ; BL: Number of L-CHS heads
|
|---|
| 50 | ; BH: Number of L-CHS sectors per track
|
|---|
| [3] | 51 | ; Corrupts registers:
|
|---|
| [227] | 52 | ; CX, DX
|
|---|
| [3] | 53 | ;--------------------------------------------------------------------
|
|---|
| [227] | 54 | AccessDPT_GetLCHStoAXBLBH:
|
|---|
| 55 | ; Return LBA-assisted CHS if LBA addressing used
|
|---|
| [173] | 56 | test BYTE [di+DPT.bFlagsLow], FLG_DRVNHEAD_LBA
|
|---|
| [227] | 57 | jz SHORT .ConvertPchsToLchs
|
|---|
| [173] | 58 |
|
|---|
| [227] | 59 | call AccessDPT_GetLbaSectorCountToBXDXAX
|
|---|
| 60 | call AtaID_GetLbaAssistedCHStoDXAXBLBH
|
|---|
| 61 | test dx, dx
|
|---|
| 62 | jnz SHORT .LimitAXtoMaxLCHScylinders
|
|---|
| 63 | cmp ax, MAX_LCHS_CYLINDERS
|
|---|
| 64 | jbe SHORT .returnLCHS
|
|---|
| 65 | .LimitAXtoMaxLCHScylinders:
|
|---|
| 66 | mov ax, MAX_LCHS_CYLINDERS
|
|---|
| 67 | .returnLCHS:
|
|---|
| 68 | ret
|
|---|
| [173] | 69 |
|
|---|
| [227] | 70 | .ConvertPchsToLchs:
|
|---|
| 71 | mov ax, [di+DPT.wPchsCylinders]
|
|---|
| 72 | mov bx, [di+DPT.wPchsHeadsAndSectors]
|
|---|
| 73 | jmp SHORT AccessDPT_ShiftPCHinAXBLtoLCH
|
|---|
| 74 |
|
|---|
| 75 |
|
|---|
| 76 | ;--------------------------------------------------------------------
|
|---|
| 77 | ; AccessDPT_GetLbaSectorCountToBXDXAX
|
|---|
| 78 | ; Parameters:
|
|---|
| 79 | ; DS:DI: Ptr to Disk Parameter Table
|
|---|
| 80 | ; Returns:
|
|---|
| 81 | ; BX:DX:AX: 48-bit sector count
|
|---|
| 82 | ; Corrupts registers:
|
|---|
| 83 | ; Nothing
|
|---|
| 84 | ;--------------------------------------------------------------------
|
|---|
| 85 | AccessDPT_GetLbaSectorCountToBXDXAX:
|
|---|
| 86 | mov ax, [di+DPT.twLbaSectors]
|
|---|
| 87 | mov dx, [di+DPT.twLbaSectors+2]
|
|---|
| 88 | mov bx, [di+DPT.twLbaSectors+4]
|
|---|
| [3] | 89 | ret
|
|---|
| 90 |
|
|---|
| 91 |
|
|---|
| 92 | ;--------------------------------------------------------------------
|
|---|
| [227] | 93 | ; AccessDPT_ShiftPCHinAXBLtoLCH
|
|---|
| [173] | 94 | ; Parameters:
|
|---|
| [227] | 95 | ; AX: P-CHS cylinders (1...16383)
|
|---|
| 96 | ; BL: P-CHS heads (1...16)
|
|---|
| [173] | 97 | ; Returns:
|
|---|
| [227] | 98 | ; AX: Number of L-CHS cylinders (1...1024)
|
|---|
| 99 | ; BL: Number of L-CHS heads (1...255)
|
|---|
| [173] | 100 | ; CX: Number of bits shifted
|
|---|
| 101 | ; Corrupts registers:
|
|---|
| 102 | ; Nothing
|
|---|
| 103 | ;--------------------------------------------------------------------
|
|---|
| [227] | 104 | AccessDPT_ShiftPCHinAXBLtoLCH:
|
|---|
| [173] | 105 | xor cx, cx
|
|---|
| 106 | .ShiftLoop:
|
|---|
| [227] | 107 | cmp ax, MAX_LCHS_CYLINDERS ; Need to shift?
|
|---|
| [173] | 108 | jbe SHORT .LimitHeadsTo255 ; If not, return
|
|---|
| 109 | inc cx ; Increment shift count
|
|---|
| [227] | 110 | shr ax, 1 ; Halve cylinders
|
|---|
| 111 | shl bl, 1 ; Double heads
|
|---|
| [173] | 112 | jmp SHORT .ShiftLoop
|
|---|
| 113 | .LimitHeadsTo255: ; DOS does not support drives with 256 heads
|
|---|
| [227] | 114 | cmp bl, cl ; Set CF if BL is zero
|
|---|
| 115 | sbb bl, ch ; If BL=0 then BL=255
|
|---|
| [173] | 116 | ret
|
|---|
| 117 |
|
|---|
| [227] | 118 |
|
|---|
| [173] | 119 | ;--------------------------------------------------------------------
|
|---|
| [3] | 120 | ; Returns pointer to DRVPARAMS for master or slave drive.
|
|---|
| 121 | ;
|
|---|
| 122 | ; AccessDPT_GetPointerToDRVPARAMStoCSBX
|
|---|
| 123 | ; Parameters:
|
|---|
| 124 | ; DS:DI: Ptr to Disk Parameter Table
|
|---|
| 125 | ; Returns:
|
|---|
| 126 | ; CS:BX: Ptr to DRVPARAMS
|
|---|
| 127 | ; Corrupts registers:
|
|---|
| 128 | ; Nothing
|
|---|
| 129 | ;--------------------------------------------------------------------
|
|---|
| 130 | ALIGN JUMP_ALIGN
|
|---|
| 131 | AccessDPT_GetPointerToDRVPARAMStoCSBX:
|
|---|
| [150] | 132 | eMOVZX bx, [di+DPT.bIdevarsOffset] ; CS:BX points to IDEVARS
|
|---|
| 133 | add bx, BYTE IDEVARS.drvParamsMaster ; CS:BX points to Master Drive DRVPARAMS
|
|---|
| [158] | 134 | test BYTE [di+DPT.bFlagsLow], FLGL_DPT_SLAVE
|
|---|
| [150] | 135 | jz SHORT .ReturnPointerToDRVPARAMS
|
|---|
| 136 | add bx, BYTE DRVPARAMS_size ; CS:BX points to Slave Drive DRVPARAMS
|
|---|
| 137 | .ReturnPointerToDRVPARAMS:
|
|---|
| [3] | 138 | ret
|
|---|
| [200] | 139 |
|
|---|
| 140 | ;--------------------------------------------------------------------
|
|---|
| 141 | ; AccessDPT_GetUnshiftedAddressModeToALZF
|
|---|
| 142 | ; Parameters:
|
|---|
| 143 | ; DS:DI: Ptr to Disk Parameter Table
|
|---|
| 144 | ; Returns:
|
|---|
| 145 | ; AL: Addressing Mode (L-CHS, P-CHS, LBA28, LBA48)
|
|---|
| 146 | ; unshifted (still shifted where it is in bFlagsLow)
|
|---|
| 147 | ; ZF: Set based on value in AL
|
|---|
| 148 | ; Corrupts registers:
|
|---|
| 149 | ; AL
|
|---|
| 150 | ;--------------------------------------------------------------------
|
|---|
| 151 | ;
|
|---|
| 152 | ; Converted to a macro since only called in two places, and the call/ret overhead
|
|---|
| 153 | ; is not worth it for these two instructions (4 bytes total)
|
|---|
| 154 | ;
|
|---|
| 155 | %macro AccessDPT_GetUnshiftedAddressModeToALZF 0
|
|---|
| 156 | mov al, [di+DPT.bFlagsLow]
|
|---|
| 157 | and al, MASKL_DPT_ADDRESSING_MODE
|
|---|
| 158 | %endmacro
|
|---|
