Regularity
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(Explaining that GOTO can be used to skip ahead, it isn't inherently a loop command) | (→The Flow of Control) | ||
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There are some important ways to complicate this straightforward program flow. All of these ways involve branching, which causes program flow to continue at some other command rather than what would is, according to left-to-right, top-to-bottom program structure, the next one. | There are some important ways to complicate this straightforward program flow. All of these ways involve branching, which causes program flow to continue at some other command rather than what would is, according to left-to-right, top-to-bottom program structure, the next one. | ||
| − | At the low level of machine code and its execution by the processor, the way program flow works is similar. Machine language is a sequence of numbers, and the next number is usually processed. However, an executing machine language program, like a high-level program in BASIC or another imperative language, can either continue to process the next instruction or can move out of sequence to process a different instruction. The standard case is when a processor continues to the next machine language instruction, just as the reader of a text moves to the next word or line. This involves incrementing the program counter so that it points to the place where the next instruction is located in memory. If the current instruction is one that can change the flow of control, however, the program may jump or branch to a new memory location and a new piece of code. | + | At the low level of machine code and its execution by the processor, the way program flow works is similar. Machine language is a sequence of numbers, and the next number is usually processed. However, an executing machine language program, like a high-level program in BASIC or another imperative language, can either continue to process the next instruction or can move out of sequence to process a different instruction. The standard case is when a processor continues to the next machine language instruction, just as the reader of a text moves to the next word or line. This involves incrementing the program counter so that it points to the place where the next instruction is located in memory. If the current instruction is one that can change the flow of control, however, the program may jump to a new memory location and a new piece of code. |
=== Conditional and Unconditional Branching === | === Conditional and Unconditional Branching === | ||
