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A form found in unstructured languages, mimicking a typical machine code instruction, would jump to (GOTO) a label or line number when the condition was met. IF..THEN..(ENDIF). Rather than being restricted to a jump, any simple statement, or nested block, could follow the THEN key keyword. This a structured form. IF..THEN..ELSE..(ENDIF). As ...
Examples of, and arguments for, Jump Tables via Function Pointer Arrays in C/C++; Example code generated by 'Switch/Case' branch table in C, versus IF/ELSE. Example code generated for array indexing if structure size is divisible by powers of 2 or otherwise. "Arrays of Pointers to Functions" by Nigel Jones
a sequence of one or more consecutively numbered basic blocks, p, (p+1), ..., q, of a code unit, followed by a control flow jump either out of the code [unit] or to a basic block numbered r, where r≠(q+1), and either p=1 or there exists a control flow jump to block p from some other block in the unit. (A basic block to which such a control ...
Historically, branch prediction took statistics, and used the result to optimize code. A programmer would compile a test version of a program, and run it with test data. The test code counted how the branches were actually taken. The statistics from the test code were then used by the compiler to optimize the branches of released code.
An indirect branch (also known as a computed jump, indirect jump and register-indirect jump) is a type of program control instruction present in some machine language instruction sets. Rather than specifying the address of the next instruction to execute , as in a direct branch , the argument specifies where the address is located.
A conditional jump in the bottom of a loop that repeats N times will be taken N-1 times and then not taken once. If the conditional jump is placed at the top of the loop, it will be not taken N-1 times and then taken once. A conditional jump that goes many times one way and then the other way once is detected as having loop behavior.
In the x86 assembly language, the JMP instruction performs an unconditional jump. Such an instruction transfers the flow of execution by changing the program counter.There are a number of different opcodes that perform a jump; depending on whether the processor is in real mode or protected mode, and an override instruction is used, the instructions may take 16-bit, 32-bit, or segment:offset ...
Duff realized that to handle cases where count is not divisible by eight, the assembly programmer's technique of jumping into the loop body could be implemented by interlacing the structures of a switch statement and a loop, putting the switch's case labels at the points of the loop body that correspond to the remainder of count/8: [1]