feat: banked program memory, FRE() function, array region, boot ROM layout

- Program memory uses MMU slot 1 banking: up to 32 × 8KB pages (~256KB)
- FRE(0) = free program memory, FRE(-1) = free variable/string space,
FRE(-2) = free array space
- Array/ALLOC storage moved to dedicated $4000-$7FFF (16KB)
- F256Header + headerdata moved to boot section in slot 3
- 5th ROM block (sb05.bin) for module code page 2

Author: mbrukner

modules/Makefile

@@ -23,10 +23,10 @@ all:
 	$(Q)$(CCOPY) ..$(S)source$(S)common$(S)generated$(S)kwdtext.dat tokeniser$(S)__kwdtext.asm
 	$(Q)$(PYTHON) _scripts$(S)makebuild.py tokeniser
 
-	$(Q)$(PYTHON) _scripts$(S)makebuild.py graphics $(BUILD_DIR)
+	$(Q)$(PYTHON) _scripts$(S)makebuild.py graphics $(BUILD_DIR) --page 2
 	$(Q)$(PYTHON) _scripts$(S)makebuild.py hardware $(BUILD_DIR)
 	$(Q)$(PYTHON) _scripts$(S)makebuild.py kernel $(BUILD_DIR)
-	$(Q)$(PYTHON) _scripts$(S)makebuild.py sound $(BUILD_DIR)
+	$(Q)$(PYTHON) _scripts$(S)makebuild.py sound $(BUILD_DIR) --page 2
 
 	$(Q)$(PYTHON) _scripts$(S)makeexport.py >$(BUILD_DIR)$(S)_exports.module.asm
 

modules/_scripts/makebuild.py

@@ -19,13 +19,17 @@
 export_re = re.compile(r"^\s*Export_(\w+)\s*:\s*(;.*)?$")
 
 
-def main(*, module_name: str, build_dir: Path) -> None:
+def main(*, module_name: str, build_dir: Path, page: int = 1) -> None:
     """Generate a single assembly build file for the specified module."""
     if not build_dir.exists():
         build_dir.mkdir(parents=True, exist_ok=True)
 
     sources = collect_sources(module_name)
-    output_path = build_dir / (module_name + ".module.asm")
+
+    if page == 2:
+        output_path = build_dir / (module_name + "_p2.module.asm")
+    else:
+        output_path = build_dir / (module_name + ".module.asm")
 
     with open(output_path, "w", encoding="utf-8") as out:
         # Write the output assembly file header
@@ -36,14 +40,14 @@ def main(*, module_name: str, build_dir: Path) -> None:
         for src in sources:
             # Scan each source file line-by-line, accumulating its exports
             # and writing its contents to the output.
-            file_exports = process_source(src, out)
+            file_exports = process_source(src, out, page=page)
             module_exports.extend(file_exports)
 
         # Dump the collected exports to a file
-        dump_exports(build_dir, module_name, module_exports)
+        dump_exports(build_dir, module_name, module_exports, page=page)
 
 
-def process_source(path: Path, out: TextIO) -> list[str]:
+def process_source(path: Path, out: TextIO, *, page: int = 1) -> list[str]:
     """Process a single source file, extracting exports and writing to output."""
     exports: list[str] = []
 
@@ -52,17 +56,29 @@ def process_source(path: Path, out: TextIO) -> list[str]:
             if m := export_re.match(line):
                 exports.append(m.group(1))
 
+            if page == 2:
+                normalized = " ".join(line.split())
+                if normalized == ".section code":
+                    out.write("\t\t.section page2\n")
+                    out.write("\t\t.logical * + $6000\n")
+                    continue
+                elif normalized == ".send code":
+                    out.write("\t\t.here\n")
+                    out.write("\t\t.send page2\n")
+                    continue
+
             out.write(f"{line.rstrip()}\n")
 
     return exports
 
 
-def dump_exports(build_dir: Path, module_name: str, exports: list[str]) -> None:
+def dump_exports(build_dir: Path, module_name: str, exports: list[str], *, page: int = 1) -> None:
     """Save module exports to the corresponding `.exports` file."""
     if not exports:
         return
 
-    with open(build_dir / (module_name + ".exports"), "w", encoding="utf-8") as out:
+    suffix = "_p2" if page == 2 else ""
+    with open(build_dir / (module_name + suffix + ".exports"), "w", encoding="utf-8") as out:
         for export in exports:
             out.write(f"{export}\n")
 
@@ -89,14 +105,16 @@ def collect_sources(module_name: str) -> list[Path]:
 
 
 if __name__ == "__main__":
-    if len(sys.argv) < 2:
-        print(
-            "Usage: python3 makebuild.py <module_name> [<build_directory>]",
-            file=sys.stderr,
-        )
-        sys.exit(1)
+    import argparse
+
+    parser = argparse.ArgumentParser(description="Build module assembly file")
+    parser.add_argument("module_name", help="Name of the module to build")
+    parser.add_argument("build_dir", nargs="?", default=".build", help="Build output directory")
+    parser.add_argument("--page", type=int, default=1, choices=[1, 2], help="Module page (1 or 2)")
+    args = parser.parse_args()
 
     main(
-        module_name=sys.argv[1],
-        build_dir=Path(sys.argv[2] if len(sys.argv) > 2 else ".build"),
+        module_name=args.module_name,
+        build_dir=Path(args.build_dir),
+        page=args.page,
     )

modules/_scripts/makeexport.py

@@ -18,15 +18,26 @@ def main(*, build_dir: Path) -> None:
 
     print(f"PagingEnabled = {1 if paging else 0}")
 
+    # Map module page number to MMU slot increments from slot 5 default (N+2):
+    #   page 1 (sb04 = N+3): 1 increment past default
+    #   page 2 (sb05 = N+4): 2 increments past default
+    page_to_incs = {1: 1, 2: 2}
+
     for module in exports:
-        print(f"\t.if {module}Integrated == 1")
-        for routine in exports[module]:
+        page = exports[module]["page"]
+        routines = exports[module]["routines"]
+        module_name = exports[module]["name"]
+        incs = page_to_incs[page]
+        print(f"\t.if {module_name}Integrated == 1")
+        for routine in routines:
             print(f"{routine}:")
             if paging:
-                print("\tinc 8+5")
+                for _ in range(incs):
+                    print("\tinc 8+5")
                 print(f"\tjsr\tExport_{routine}")
                 print("\tphp")
-                print("\tdec 8+5")
+                for _ in range(incs):
+                    print("\tdec 8+5")
                 print("\tplp")
                 print("\trts")
             else:
@@ -35,19 +46,33 @@ def main(*, build_dir: Path) -> None:
         print("\t.endif")
 
 
-def read_exports(build_dir: Path) -> dict[str, list[str]]:
-    """Read all `.exports` files from the build directory."""
-    all_exports: dict[str, list[str]] = {}
+def read_exports(build_dir: Path) -> dict[str, dict]:
+    """Read all `.exports` files from the build directory.
+
+    Files named `<module>_p2.exports` are treated as page 2 exports
+    (requiring double inc/dec 8+5). All others are page 1.
+    """
+    all_exports: dict[str, dict] = {}
 
     if not build_dir.exists():
         return all_exports
 
     # Find all .exports files in the build directory
     for file_path in build_dir.glob("*.exports"):
         if module_exports := read_module_exports(file_path):
-            module_name = file_path.stem  # filename without extension
+            stem = file_path.stem  # filename without extension
+            if stem.endswith("_p2"):
+                module_name = stem[:-3]  # strip _p2 suffix
+                page = 2
+            else:
+                module_name = stem
+                page = 1
             module_exports.sort()
-            all_exports[module_name] = module_exports
+            all_exports[stem] = {
+                "name": module_name,
+                "page": page,
+                "routines": module_exports,
+            }
 
     return all_exports
 

modules/hardware/dos.asm

@@ -0,0 +1,86 @@
+; ************************************************************************************************
+; ************************************************************************************************
+;
+;		Name:		dos.asm
+;		Purpose:	DOS boot (module code)
+;		Created:	13th January 2023
+;		Author:		Paul Robson (paul@robsons.org.uk)
+;
+; ************************************************************************************************
+; ************************************************************************************************
+
+		.section code
+
+Export_EXTBootXA:
+		pha
+		phx
+		jsr		IsDestructiveActionOK
+		plx
+		pla
+		bcc		_action_ok
+		jmp		WarmStart
+
+_action_ok:
+		sta		zTemp0+0
+		stx		zTemp0+1
+
+		ldx		#0
+		ldy		#0
+
+_copy_next_string:
+		tya
+		clc
+		adc		#<ArgumentStrings
+		sta		ArgumentArray,x
+		inx
+		lda		#>ArgumentStrings
+		adc		#0
+		sta		ArgumentArray,x
+		inx
+
+_copy_string:
+		lda		(zTemp0),y
+		beq		_copy_done
+		cmp		#' '
+		beq		_skip_spaces
+		sta		ArgumentStrings,y
+		iny
+		bra		_copy_string
+
+_skip_spaces:
+		lda		#0
+		sta		ArgumentStrings,y
+		iny
+		lda		(zTemp0),y
+		beq		_copy_done
+		cmp		#' '
+		beq		_skip_spaces
+		bra		_copy_next_string
+
+_copy_done:
+		lda		#0
+		sta		ArgumentStrings,y
+
+		stx		kernel.args.extlen
+
+		stz		ArgumentArray,x
+		stz		ArgumentArray+1,x
+
+		lda		#<ArgumentArray
+		sta		kernel.args.ext
+		lda		#>ArgumentArray
+		sta		kernel.args.ext+1
+
+		lda		#<ArgumentStrings
+		sta		kernel.args.buf
+		lda		#>ArgumentStrings
+		sta		kernel.args.buf+1
+
+		jsr		kernel.RunNamed
+
+		jsr		ResetTokenBuffer
+		.error_noprogram
+
+		jmp		WarmStart
+
+		.send code