NonStop S-Series Server Description Manual (G06.24+)

TNS Instruction Set
HP NonStop S-Series Server Description Manual—520331-003
11-41
Additional Operating-System-Only Instructions
other code segment specifies a procedure entry point within that segment. The
address space mappings of relative segments 2 and 3 (current code segment and
latest user code segment) are updated. See detailed descriptions in Section 6, TNS
Execution Modes.
XMSK (000064). Exchange MASK With A. The contents of the MASK register are
interchanged with the contents of the A register. This is a privileged instruction.
XOR (000012). Logical Exclusive OR A With B. The two words in A and B of the
register stack are combined by a logical exclusive OR. The two words are then
deleted, and the result is pushed onto the stack. Condition Code is set. (For an
example, see Figure 11-5 on page 11-6.)
XSMG (000343). Compute Checksum in Current Data. Starting at the address
defined in register B, for a count of words defined in register A, the XSMG instruction
exclusive-ORs each word into register C. When the count goes to zero, the two top
words on the stack are deleted, leaving the final checksum in register A. The address
in B refers to the current data segment only.
XSMX (000333). Compute Checksum Extended. Starting at the memory location
defined by the 32-bit even-byte address in CB, for a count of words defined in
register A, the XSMX instruction exclusive-ORs each word into register D. When the
count goes to zero, the three top words on the stack are deleted, leaving the final
checksum in register A.
ZERD (000002). Zero Double. A doubleword zero is pushed onto the top of the
register stack (BA). Condition Code is set.
Additional Operating-System-Only Instructions
The following groups of instructions, most of them privileged, are used solely to
implement certain operating system and diagnostic functions in millicode. These
instructions are not intended for use in any user applications.