Cray CRAY-1 - Memory Error Data

I
Mode register (M) - 4 bits without MMI option; 5 bits with option
Exchange address register (XA) - 8 bits
Vector length register (VL) - 7 bits
Flag register (F) - 9 bits
Current contents of the eight A registers
Current contents of the eight S registers
The exchange package contents are arranged in a 16-word block as shown
in figure 3-8. Data is swapped from memory to the computer operating
registers and back to memory by the exchange sequence. This sequence
exchanges the data in a currently active
exchange package, which is
residing in the operating registers, with an inactive exchange package
in memory. The XA address of the currently active exchange package
specifies the address of the inactive exchange package to be used in
the
swap. The data is exchanged and a new program execution interval
is initiated by the exchange sequence.
The B register, T register, and V register contents are not swapped in
the
exchange sequence. The data in these registers must be stored and
replaced as required by specific coding in the monitor program which
supervises the object program execution.
Memory error data
Two bits in the Mode (M) register determine whether or not the exchange
package contains data relevant to a memory error if one occurs prior
to an exchange sequence. These are bit 36, the "Interrupt on correctable
memory error bit" and bit 38, the "Interrupt on uncorrectable memory
error bit". The error data, consisting of four fields of information,
appears in the
exchange package if bit 38 is set and an uncorrectable
memory error is detected or if bit 36 is set and correctable memory error
is encountered.
Error type
(E) - The type of error encountered, uncorrectable or
correctable,
is indicated in bits 0 and 1 of the first word of the
exchange package. Bit 0 is set for an uncorrectable memory error; bit 1
is set for a correctable memory error.
2240004 3-41
E