add docs for debug output

Cargo.lock

@@ -599,7 +599,7 @@ checksum = "b365fabc795046672053e29c954733ec3b05e4be654ab130fe8f1f94d7051f35"
 [[package]]
 name = "curlywas"
 version = "0.1.0"
-source = "git+https://github.com/exoticorn/curlywas.git?rev=c22297e#c22297ea82977ac06373d629fb273a795322d788"
+source = "git+https://github.com/exoticorn/curlywas.git?rev=0a0d90c#0a0d90c8013f1d7856a9b71a19d3d006300f31f9"
 dependencies = [
  "anyhow",
  "ariadne",

Cargo.toml

@@ -16,7 +16,7 @@ anyhow = "1"
 minifb = { version = "0.22", default-features = false, features = ["x11"], optional = true }
 notify = "4"
 pico-args = "0.4"
-curlywas = { git = "https://github.com/exoticorn/curlywas.git", rev = "c22297e" }
+curlywas = { git = "https://github.com/exoticorn/curlywas.git", rev = "0a0d90c" }
 wat = "1"
 uw8-tool = { path = "uw8-tool" }
 same-file = "1"

platform/Cargo.lock

@@ -146,7 +146,7 @@ checksum = "7a81dae078cea95a014a339291cec439d2f232ebe854a9d672b796c6afafa9b7"
 [[package]]
 name = "curlywas"
 version = "0.1.0"
-source = "git+https://github.com/exoticorn/curlywas.git?rev=c22297e#c22297ea82977ac06373d629fb273a795322d788"
+source = "git+https://github.com/exoticorn/curlywas.git?rev=0a0d90c#0a0d90c8013f1d7856a9b71a19d3d006300f31f9"
 dependencies = [
  "anyhow",
  "ariadne",

platform/Cargo.toml

@@ -6,7 +6,7 @@ edition = "2021"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-curlywas = { git="https://github.com/exoticorn/curlywas.git", rev="c22297e" }
+curlywas = { git="https://github.com/exoticorn/curlywas.git", rev="0a0d90c" }
 uw8-tool = { path="../uw8-tool" }
 anyhow = "1"
 lodepng = "3.4"

platform/src/platform.cwa

@@ -320,8 +320,10 @@ global mut controlCodeLength = 0;
 fn printSingleChar(char: i32) {
     if char >= 4 & char <= 6 {
         outputChannel = char - 4;
+        if !outputChannel {
             textCursorX = 0;
             textCursorY = 0;
+        }
         return;
     }
 

site/content/docs.md

@@ -226,13 +226,13 @@ Characters 0-31 are control characters and don't print by default. They take the
 Avoid the reserved control chars, they are currently NOPs but their behavior can change in later MicroW8 versions.
 
 | Code  | Parameters | Operation                                  |
-| ----- | ---------- | ------------------------------------ |
+| ----- | ---------- | ------------------------------------------ |
 | 0     | -          | Nop                                        |
 | 1     | char       | Print char (including control chars)       |
 | 2-3   | -          | Reserved                                   |
-| 4     | -          | Switch to normal mode                |
+| 4     | -          | Switch to normal mode, reset cursor to 0,0 |
 | 5     | -          | Switch to graphics mode                    |
-| 6     | -          | Reserved                             |
+| 6     | -          | Switch output to (debug) console           |
 | 7     | -          | Bell / trigger sound channel 0             |
 | 8     | -          | Move cursor left                           |
 | 9     | -          | Move cursor right                          |
@@ -249,6 +249,21 @@ Avoid the reserved control chars, they are currently NOPs but their behavior can
 
 (*) In graphics mode, the x coordinate is doubled when using control char 31 to be able to cover the whole screen with one byte.
 
+#### Debug output
+
+Control code 6 switches all text output (except codes 4 and 5 to switch output back to the screen) to the console. Where exactly this ends
+up (if at all) is an implementation detail of the runtimes. The native dev-runtime writes the debug output to `stdout`, the web runtime to
+the debug console using `console.log`. Both implementation buffer the output until they encounter a newline character (10) in the output stream.
+
+There may be future runtimes that ignore the debug output completely.
+
+In CurlyWas, a simple way to log some value might look like this:
+```
+printChar('\06V: '); // switch to console out, print some prefix
+printInt(some_value);
+printChar('\n\4'); // newline and switch back to screen
+```
+
 ### fn printChar(char: i32)
 
 Prints the character in the lower 8 bits of `char`. If the upper 24 bits are non-zero, right-shifts `char` by 8 bits and loops back to the beginning.