NAME

mem − memory pseudo-device

SYNOPSIS

{
"mem",_nulldev,_memopen,
_memstrategy,_nulldev,_nulldev,
DTTYPE_CHAR,
DTFS_NONE,"memory pseudo-device"
}

DESCRIPTION

Mem is a pseudo-device that allows commands that normally operate on devices to transfer information to and from memory.  The mem device may be used to dump the contents of memory to tape or load firmware from tape to a VME peripheral that has address space on the VME bus.  The mem device is referenced as:
mem(base_addr,width,address_modifier)
Base_addr specifies the base address of the transfer to or from memory relative to the requested address space specified by address_modifier.  Width may be 1, 2, or 4 to request byte, short, or word transfers from the indicated memory space.  Address_modifier indicates the appropriate address space to use when performing the transfer.  If address_modifier is non-zero, it specifies a VME bus address modifier to be generated.  The R2300 cpu board can generate address modifiers 0x9, 0x29, 0x2d, and 0x3d on the VME bus, these are the only non-zero address modifiers that are legal.  If address_modifier is zero, addresses are in the R2000 address space; i.e. 0 is the base of KUSEG, 0x80000000 is the base of K0SEG, 0xa0000000 is the base of K1SEG, and 0xc0000000 is the base of K2SEG.  See the R2000 Processor manual for a description of the R2000 address space. 

DIAGNOSTICS

unsupported address modifier
An address modifier other than 0, 0x9, 0x29, 0x2d, or 0x3d was specified.

illegal width
A width other than 1, 2, or 4 was specified.

base address outside region
The base address specified is large than the size of the address space specified by address_modifier. 

SEE ALSO

R2000 User’s Guide