Unterschiede

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--- pfw:togglealedwithsingletasto [2025-06-21 21:30] – [Pseudo code for the mplementation] mka
+++ pfw:togglealedwithsingletasto [2025-06-22 00:20] (aktuell) – geöscht mka
@@ Zeile 1: / Zeile 1: @@
-===== Switch LED on and off in a button  =====
-Hier wird eine LED sauber an- und wieder aus geschaltet.
-==== Idea ====
-Als Modell diente der Taster, der auch schon in der Demo von tasto und clavis benutzt worden ist. Im Taster ist eine LED integriert. Die soll getoggle werden.
-bild
-==== Implementation ====
-It's assumed that a program periodically checks whether the switch has been pressed and then changes the state of the LED.
-The challenge is to eliminate switch bounce so that the user gets a smooth, reliable impression of the changes. The response should be fast enough to be instantaneous, but slow enough to allow for a safe switchover.
-==== Pseudo code for the toggleLED implementation ====
-//What [[en:pfw:pseudocode|Pseudo code]] is.//
-<code>
-Function: init ( -- )
-  output address (possibly right aligned)
-  output ":" and some space
-  LOOP i from 0 to 15:
-     output byte in memory at (address+i) as two hexadecimal digits (or in another radix if desired)
-     output some space
-  LOOP i from 0 to 15:
-     output byte in memory at (address+i) as an ASCII character, "." if that character is a control character (byte<32)
-Function: dump ( address length -- )
-   WHILE length is positive:
-        dump-line at address
-        increase address by 16
-        decrease length by 16
-</code>
-==== Minimal Forth implementation of DUMP: ====
-You can find a [[https://github.com/Project-Forth-Works/Project-Forth-Works.github.io/blob/main/minimalforth.md|Minimal Forth]] implementation of DUMP in [[en:pfw:dump-minimal_forth.fs|dump-Minimal_Forth.fs]].
-You can use it as follows:
-<code forth>
-  ok
-Create x 100 allot  ok
-x 100 dump
-D694: 05 61 6C 6C 6F 74 08 00 DF 14 00 00 C1 00 08 00   .allot..?...?...
-D6A4: 1F 18 00 00 C1 00 08 00 6F 10 00 00 C1 00 08 00   ....?...o...?...
-D6B4: 4F 10 00 00 C2 00 08 00 1F 13 00 00 C2 00 08 00   O...?.......?...
-D6C4: 8F 30 00 00 C2 00 08 00 DF 14 00 00 C2 00 08 00   ?0..?...?...?...
-D6D4: 1F 18 00 00 C2 00 08 00 6F 10 00 00 C2 00 08 00   ....?...o...?...
-D6E4: 4F 10 00 00 C3 00 08 00 8F 30 00 00 C3 00 08 00   O...?...?0..?...
-D6F4: 5F 13 00 00                                       _... ok
-</code>
-As the original Minimal Forth has no output facility other than ''emit'' and ''.s'' (specifically no number formatting and no ''.'' or ''.r'')
-this implementation seems to be over complicated.
-We extended Minimal Forth to [[https://github.com/Project-Forth-Works/Project-Forth-Works.github.io/blob/main/minimalforth.md|GenericForth]] to get a
-more useful small Forth.
-A DUMP utility in **GenericForth** can be found in [[en:pfw:dump-genericforth.f|dump-GenericForth.f]]
-This example is factored using the pseudo code description. The character output has been factored into the useful word PEMIT ( char -- ) too.
-==== Various DUMP Implementations ====
-Other DUMP implementations can be found at the end of this description.
-Your system might lack right justified number output or even BASE for printing numbers in other radix systems. The sample implementation in [[pfw:twomoredumps.f|twomoredumps.f]] show how to circumvent this.
-==== Background information ====
-More about the DUMP utility can found at the [[https://en.wikipedia.org/wiki/Hex_dump|Wikipedia page for hexdump]]
-Some Forth DUMP implementations display a fixed amount of bytes and leave the updated address on the stack so that
-you can invoke DUMP repeatedly to display successive regions of memory.
-==== Possible pitfalls with DUMP ====
-Some systems have hardware memory protection that is triggered if you access memory outside the reserved area.
-The dump utility can do so by trying to show this forbidden memory. Triggered memory protect might stop the current process and
-terminate your session. If necessary a suitable test for the validity of used addresses might be reasonable on such systems so that
-dump can issue a normal error message (or display dummy data) in theses cases and leave the system / session otherwise intact.
-==== Contributions ====
-<html><h2 style="background-color:yellow">Alternative Implementations</h2></html>
-You have another approach to DUMP?
-Please add it at the end of this document.
-~~DISCUSSION~~