The simplest solution is to cut the aperture size by the amount
of video RAM installed. This way, accesses to the big-endian
aperture located above the installed VRAM will be catched and
reported by the MMU.
The disk cache is unchanged. data_ptr continues to be only used for the user data sector area for each block. The other sector areas (synch, header, etc.) are filled in while reading.
has_data and get_data exist as a way to bypass data_ptr for parts of the transfer outside the user data sector area of each block. The default behaviour is defined in atabasedevice and is overridden by atapicdrom for the Read CD command. atapicdrom has a flag doing_sector_areas to control the behavior of the get_data method. When the flag is true, the sector_areas, current_block, and current_block_byte are used for selecting the correct data from one of the sector areas. The Read CD command initializes those variables. xfer_cnt remains the total number of bytes to be transferred and is now not necessarily the same as the number of disk image blocks read into the disk cache.
lba_to_msf is used to fill in the header. The values was not verified using a real CD.
Mac OS X just cares about the Mode in the header. For now, only the synch and header and user data areas are filled in. The other areas read as all zeros.
In Read TOC format 2, Mac OS X passes zero for Session Number. I believe Read TOC is supposed to return the first session starting from that number so it should return info for Session 1 as it would if Mac OS X passed 1 for the Session Number.
It was possible to corrupt New World nvram using dingusppc setenv command.
- setenv must call get_config_vars to set data_length so that it can calculate free space.
- data_length represents the number of bytes taken by nvram variables including the terminating null for the value (name, '=', value, '\0'). Previously, it did not include the terminating null.
- The list of variables and values ends at a '\0' or at pos == 4096 bytes. Previously, data_length wouldn't get set if pos >= 4096.
- Allow setenv to create new nvram variables.
- Since data_length now represents the total number of used bytes, free_space now represents the actual free space, so use > free_space (instead of >= free_space) to determine insufficient space.
- While parsing nvram variable name, do not read beyond 4096 bytes.
- Use a different error message for each problem that can occur while parsing nvram variable name.
If a nvram variable has CRLF or CR, replace them with LF so each line appears on a new line in the console output.
Also, add indent to each line so that each line appears only in the value column and not in the name column.
