Topic       : The ATARI Compendium
Author      : Scott Sanders / JAY Software
Version     : 1.25 (20/6/2003)
Subject     : Documentation
Nodes       : 1117
Index Size  : 32614
HCP-Version : 6
Compiled on : Atari
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@lang       : en
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View Ref-FileNVMaccess()                                                           XBIOS

Syntax

WORD NVMaccess( op, start, count, buffer )
WORD op, start, count;
char *buffer;

Function      NVMaccess() reads/modifies data in non-volatile (battery
              backed-up) memory.

Opcode        46 (0x2E)

Availability  This function's availability is variable. If it returns 0x2E
              (its opcode) when called, the function is non-existent and
              the operation was not carried out.

Parameters    op indicates the operation to perform as follows:

              Name      op   Meaning

              NVM_READ   0   Read count bytes of data starting at offset
                             start and place the data in buffer.

              NVM_WRITE  1   Write count bytes of data from buffer
                             starting at offset start.

              NVM_RESET  2   Resets and clears all data in non-volatile
                             memory.

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  NVMaccess() returns 0 if the operation succeeded or
              a negative error code otherwise.

Caveats       All of the locations are reserved for use by Atari and none
              are currently documented.

Comments      Currently there is a total of 50 bytes in non-volatile RAM.