Direct mode

This article covers the instant execution mode , not to be confused with Immediate mode (computer graphics) , a concept of API design in graphics libraries.

Direct mode is a term from computer science that refers to the immediate execution of an instruction outside the context of a program . The instruction is immediately after the input is completed, e.g. B. with Enteror Return, and the result is displayed on the screen .

In contrast to this, nothing is carried out in program mode until a specific instruction is given and a program is started as a result. Some instructions can be used in Direct Mode and Program Mode, while others are exclusive to one mode or the other. (The BASICRUN statement is an example of a direct mode statement.)

Direct mode was most commonly used on 8-bit systems such as the Commodore 64 and Atari 800 . However, instructions entered on a Unix shell can also be regarded as the direct mode equivalent of shell scripts , and modern interpreted languages ​​such as Python and Perl contain Read-Eval-Print-Loop (REPL) shells in which instructions can be used immediately Evaluation and execution can be entered.

Even modern integrated development environments often offer a direct mode, where during debugging with the program execution stopped, instructions in the current scope can be executed immediately and the result is displayed on the screen.

example

Program mode:

10 PRINT "HELLO WIKIPEDIA"
READY.
RUN
HELLO WIKIPEDIA
READY.

Direct mode:

PRINT "HELLO WIKIPEDIA"
HELLO WIKIPEDIA
READY.

See also

• Lisp machine
• interpreter

Individual evidence

1. ↑ C128 System Guide: Section 3. Retrieved May 2, 2020 (Canadian English).