There are also machines ( or particular instructions ) where the condition may be checked by the jump instruction itself, such as " branch if register X negative ".
22.
If an operating system kernel used a different virtual address space for jump instructions than for all others, how would the C language standard have to change to accommodate this?
23.
Machine level jump instructions typically have " unconditional " and " conditional " forms where the latter may be " taken " or " not taken " depending on some condition.
24.
Without branch prediction, the processor would have to wait until the conditional jump instruction has passed the execute stage before the next instruction can enter the fetch stage in the pipeline.
25.
Many computers directly support subroutines by providing a type of jump that " remembers " the location it jumped from and another instruction to return to the instruction following that jump instruction.
26.
If particular implementation stops the computer if it encounters an unknown opcode or it implements additional unconditional jump instruction with opcode " 111aaaaa ", then such behaviour can be used as follows:
27.
When the OS VBI routine is enabled direct updates to the ANTIC DLIST registers by the CPU or the ANTIC Jump instructions will be overwritten by the OS during the next Vertical Blank.
28.
:I assume, incidentally, that when you say " a different virtual address space for jump instructions " you include conditional jumps ( branches ) .-- Talk 16 : 43, 20 April 2010 ( UTC)
29.
However, a program could not sense whether the CPU was in the process of deferring the effect of a CIF instruction ( whether it had executed a CIF and not yet executed the matching jump instruction ).
30.
In the words of Guy L . Steele, " in general, procedure calls may be usefully thought of as GOTO statements which also pass parameters, and can be uniformly coded as [ machine code ] JUMP instructions ."
