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NVMaccess() à 2009-06-06 23:55:08.
WORD Logbase( op, start, count, buffer )
NVMaccess() is the function to use if you want to read or write data store in Non Volatile RAM (NVRAM in short), which is preserved between power-off using a battery (also used by the clock).
Opcode
46 (0x2e)
Availability
Like some other XBIOS functions, if the return code is 0x2e, it means the function is not supported.
Parameters
op is the operation to perform on the NVRAM data:
| Name |
Value |
Operation |
| NVM_READ |
0 |
Read bytes from NVRAM to buffer in RAM |
| NVM_WRITE |
1 |
Write bytes from buffer in RAM to NVRAM |
| NVM_RESET |
2 |
Reset NVRAM content |
start is the start offset in the NVRAM buffer.
count is the number of bytes to process.
buffer is a pointer to a buffer where the function will read from/write to data.
Binding
pea buffer
move.w count,-(sp)
move.w start,-(sp)
move.w op,-(sp)
move.w #$2e,-(sp)
trap #14
lea 12(sp),sp
Return Value
Returns 0 if succeeded, or a negative error code.
NVRAM content
Here are currently known values stored in the NVRAM. They were not documented by Atari.
| Name |
Offset |
Value |
Description |
| NVRAM_BOOT |
1 |
- |
OS preference |
| - |
- |
0x00 |
None |
| - |
- |
0x08 |
Magic |
| - |
- |
0x10 |
Linux |
| - |
- |
0x20 |
NetBSD? |
| - |
- |
0x40 |
SVR4 |
| - |
- |
0x80 |
TOS |
| NVRAM_LANGUAGE |
6 |
- |
Language |
| - |
- |
0 |
US English |
| - |
- |
1 |
German |
| - |
- |
2 |
French |
| - |
- |
3 |
UK English |
| - |
- |
4 |
Spanish |
| - |
- |
5 |
Italian |
| NVRAM_KEYBOARD |
7 |
- |
Keyboard mapping |
| NVRAM_DATE_FMT |
8 |
- |
Date and time format (bitmask between date and time values) |
| - |
- |
0x00 |
Time: 12 hours |
| - |
- |
0x10 |
Time: 24 hours |
| - |
- |
0x00 |
Date: MMDDYY |
| - |
- |
0x01 |
Date: DDMMYY |
| - |
- |
0x02 |
Date: YYMMDD |
| - |
- |
0x03 |
Date: YYDDMM |
| NVRAM_DATE_SEP |
9 |
- |
Date separator (ASCII character code) |
| NVRAM_DELAY |
10 |
0 to 255 |
Boot delay (in seconds) |
| NVRAM_VIDEO_HI |
14 |
- |
High byte of video mode code |
| NVRAM_VIDEO_LO |
15 |
- |
Low byte of video mode code |
| NVRAM_SCSI_ARB |
16 |
SCSI arbitration (bitmask) |
| - |
- |
0x80 |
Enabled |
| - |
- |
0 to 7 |
SCSI device number for Falcon |