附件2-6：BM可引导光盘格式 6.3 INT 13 Function 4C-Initiate Disk Emulation Boot This function takes a pointer to the Specification Packet and uses it to reboot the system from scratch.This function only returns if the supplied packet does not contain a pointer to a bootable disk image. Registers at call: AH=4C AL=00 DS:SI-Specification Packet as defined in figure 9 Registers on return AX-Return Codes CF-Set if system failed to boot CF Clear will not occur because when this function succeeds no return is generated. 6.4 INT 13 Function 4D-Return Boot Catalog This function takes a drive number in DL,a command packet in DS:SI,and returns the requested number of sectors from the boot catalog. Registers at call: AH=4D AL=00 DS:SI-Pointer to command packet as defined in figure 8 Registers on return: AX-Return Codes CF-Clear if successful CF-Set if device is not an emulated CD,or command packet is out of bounds Offset Type Description 0 Byte Packet Size in bytes,currently 8 Byte Sector count.Number of sectors in the boot catalog to transfer 2-5 Dword Pointer to the buffer where the boot catalog will be moved 6-7 Word Beginning sector to transfer.This number is relative to the start of the boot catalog. The initial call to INT 13 Function 4D should always set this value to 0. Figure 8-Command Packet Version 1.0 Copyright1994 Phoenix Technologies and IBM All Rights Reserved. Page 15附件2-6：IBM可引导光盘格式 Version 1.0 Copyright  1994 Phoenix Technologies and IBM All Rights Reserved. Page 15 6.3 6.3 INT INT 13 13 Function Function Function Function 4C 4C - - Initiate Initiate Initiate Initiate Disk Disk Emulation Emulation Emulation Emulation & & Boot Boot This function takes a pointer to the Specification Packet and uses it to reboot the system from scratch. This function only returns if the supplied packet does not contain a pointer to a bootable disk image. Registers at call: AH = 4C AL = 00 DS:SI - Specification Packet as defined in figure 9 Registers on return AX - Return Codes CF - Set if system failed to boot CF Clear will not occur because when this function succeeds no return is generated. 6.4 6.4 INT INT 13 13 Function Function Function Function 4D 4D - - Return Return Boot Boot Catalog Catalog Catalog Catalog This function takes a drive number in DL, a command packet in DS:SI, and returns the requested number of sectors from the boot catalog. Registers at call: AH = 4D AL = 00 DS:SI - Pointer to command packet as defined in figure 8 Registers on return: AX - Return Codes CF - Clear if successful CF - Set if device is not an emulated CD, or command packet is out of bounds Figure 8 - Command Packet Offset Offset Type Type Description Description Description Description 0 Byte Packet Size in bytes, currently 8 1 Byte Sector count. Number of sectors in the boot catalog to transfer 2-5 Dword Pointer to the buffer where the boot catalog will be moved 6-7 Word Beginning sector to transfer. This number is relative to the start of the boot catalog. The initial call to INT 13 Function 4D should always set this value to 0