bytecode/src/lib.rs

@@ -89,6 +89,7 @@ pub enum DisasmError<'a> {
     InstructionOutOfBounds(&'a str),
     FmtFailed(core::fmt::Error),
     HasOutOfBoundsJumps,
+    HasDirectInstructionCycles,
 }
 
 #[cfg(feature = "disasm")]
@@ -112,6 +113,9 @@ impl core::fmt::Display for DisasmError<'_> {
                 "the code contained jumps that dont got neither to a \
                 valid symbol or local insturction"
             ),
+            DisasmError::HasDirectInstructionCycles => {
+                writeln!(f, "found instruction that jumps to itself")
+            }
         }
     }
 }
@@ -141,6 +145,7 @@ pub fn disasm<'a>(
 
     let mut labels = BTreeMap::<u32, u32>::default();
     let mut buf = Vec::<instrs::Oper>::new();
+    let mut has_cycle = false;
     let mut has_oob = false;
 
     '_offset_pass: for (&off, &(name, len, kind)) in functions.iter() {
@@ -169,6 +174,8 @@ pub fn disasm<'a>(
                     _ => continue,
                 };
 
+                has_cycle |= rel == 0;
+
                 let global_offset: u32 = (offset + rel).try_into().unwrap();
                 if functions.get(&global_offset).is_some() {
                     continue;
@@ -280,5 +287,9 @@ pub fn disasm<'a>(
         return Err(DisasmError::HasOutOfBoundsJumps);
     }
 
+    if has_cycle {
+        return Err(DisasmError::HasDirectInstructionCycles);
+    }
+
     Ok(())
 }

lang/README.md

@@ -528,6 +528,99 @@ main := fn(): int {
 
 ### Purely Testing Examples
 
+#### smh_happened
+```hb
+render := @use("render.hb")
+
+main := fn(): void {
+	render.init(true)
+	return
+}
+
+// in module: stn.hb
+
+string := @use("string.hb")
+dt := @use("dt.hb")
+memory := @use("memory.hb")
+
+// in module: memory.hb
+
+PAGE_SIZE := 4096
+MAX_ALLOC := 0xFF
+
+alloc := fn($Expr: type, num: int): ^Expr {
+	pages := 1 + @bitcast(@sizeof(Expr)) * num / PAGE_SIZE
+	if pages <= MAX_ALLOC {
+		return @bitcast(@inline(request_page, pages))
+	}
+	ptr := @inline(request_page, 0xFF)
+	remaining := pages - MAX_ALLOC
+	loop if remaining <= 0 break else {
+		if remaining < MAX_ALLOC {
+			request_page(remaining)
+		} else {
+			request_page(MAX_ALLOC)
+		}
+		remaining -= MAX_ALLOC
+	}
+	return @bitcast(ptr)
+}
+
+request_page := fn(page_count: u8): ^u8 {
+	msg := "\{00}\{01}xxxxxxxx\0"
+	msg_page_count := msg + 1;
+	*msg_page_count = page_count
+	return @eca(3, 2, msg, 12)
+}
+
+// in module: string.hb
+
+length := fn(ptr: ^u8): uint {
+	len := @as(uint, 0)
+	loop if *(ptr + len) == 0 break else len += 1
+	return len
+}
+
+// in module: dt.hb
+
+.{string} := @use("stn.hb")
+
+get := fn($Expr: type, query: ^u8): Expr {
+	return @eca(3, 5, query, @inline(string.length, query))
+}
+
+// in module: render.hb
+
+.{dt, memory} := @use("stn.hb")
+Color := packed struct {b: u8, g: u8, r: u8, a: u8}
+
+Surface := struct {
+	buf: ^Color,
+	width: int,
+	height: int,
+}
+
+new_surface := fn(width: int, height: int): Surface {
+	return .(
+		@inline(memory.alloc, Color, width * height),
+		width,
+		height,
+	)
+}
+
+init := fn(doublebuffer: bool): Surface {
+	framebuffer := dt.get(^Color, "framebuffer/fb0/ptr\0")
+	width := dt.get(int, "framebuffer/fb0/width\0")
+	height := dt.get(int, "framebuffer/fb0/height\0")
+	if doublebuffer {
+		return new_surface(width, height)
+	} else {
+		return .(framebuffer, width, height)
+	}
+}
+
+```
+
 #### wide_ret
 ```hb
 OemIdent := struct {
@@ -926,14 +1019,6 @@ main := fn(arg: int): int {
 #### exhaustive_loop_testing
 ```hb
 main := fn(): int {
-	loop break
-
-	x := 0
-	loop {
-		x += 1
-		break
-	}
-
 	if multiple_breaks(0) != 3 {
 		return 1
 	}
@@ -958,8 +1043,7 @@ main := fn(): int {
 		return 6
 	}
 
-	loop {
+	return 0
-	}
 }
 
 multiple_breaks := fn(arg: int): int {