June 23, 2010 |
5 <8GB INT 13h Functions (Conventional Functions)
The Conventional INT 13h functions can address a maximum of 8.4GB of device space. Sector sizes shall be exactly 512 bytes. The Conventional INT 13h functions pass all parameters in registers using the following template (see table 6) unless otherwise specified:
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| Table 6 — Conventional Register Definitions | |
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AH | INT 13h function number (Range is 00h through 3Fh) | |||
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AL | Number of sectors to transfer | |||
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CH | Low 8 bits of Cylinder | |||
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CL |
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| Bit | Description |
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| 5:0 | Sector number. This value shall be >= 01h and <= 3Fh |
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| 7:6 | High order 2 bits of the cylinder |
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DH | Head Number | |||
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DL |
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| Bit | Description |
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| 6:0 | Drive number |
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| 7 | Set to 1 for Fixed media, clear to 0 for removable media |
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ES:BX | This register contains the buffer pointer (i.e., the beginning address of the buffer in system memory). | |||
| Commands that move data from the device to memory shall use this pointer as the destination for | |||
| the data. Commands that move data from memory to the device shall use this pointer as the source | |||
| for the data to be transferred. | |||
Working Draft Enhanced Disk Drive - 4 | 13 |
