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COND: condition
Syntax: [ IF cond ] RTI ;
Permissible conds (see Table 15.9)
EQ NE GT GE LT
LE NEG POS AV NOT AV
AC NOT AC MV NOT MV NOT CE
Example: IF MV RTI ;
Description: Test the optional condition and, if true, then perform the
specified return. If the condition is not true then perform a no-operation.
Omitting the condition performs the return unconditionally. RTI executes
a program return from an interrupt service routine. The address on top of
the PC stack is popped and is used as the return address. The value on top
of the status stack is also popped, and is loaded into the arithmetic status
(ASTAT), mode status (MSTAT) and the interrupt mask (IMASK)
registers.
If RTI is the last instruction inside a DO UNTIL loop, you must ensure
that the loop stacks are properly handled.
Status Generated: None affected.
Instruction Field:
Conditional Return, Instruction Type 20:
23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
0 0 0 0 1 0 1 0 0 0 0 0 0 0 0 0 0 0 0 1 COND
PROGRAM FLOW
RTI
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