Fixed an assembler and a disassembler bug.

src/core/util.ts

@@ -0,0 +1,28 @@
+export function arrays_equal<T>(
+    a: T[],
+    b: T[],
+    equal: (element_a: T, element_b: T) => boolean = (a, b) => a === b,
+): boolean {
+    const len = a.length;
+
+    if (len !== b.length) return false;
+
+    for (let i = 0; i < len; i++) {
+        if (!equal(a[i], b[i])) return false;
+    }
+
+    return true;
+}
+
+export function array_buffers_equal(a: ArrayBuffer, b: ArrayBuffer): boolean {
+    if (a.byteLength !== b.byteLength) return false;
+
+    const a_arr = new Uint8Array(a);
+    const b_arr = new Uint8Array(b);
+
+    for (let i = 0; i < a_arr.length; i++) {
+        if (a_arr[i] !== b_arr[i]) return false;
+    }
+
+    return true;
+}

src/quest_editor/scripting/assembly.ts

@@ -59,26 +59,32 @@ export function assemble(
 }
 
 class Assembler {
-    private lexer = new AssemblyLexer();
+    private readonly lexer = new AssemblyLexer();
     private line_no!: number;
     private tokens!: Token[];
     private object_code!: Segment[];
-    // The current segment.
+    /**
+     * The current segment.
+     */
     private segment?: Segment;
     private warnings!: AssemblyWarning[];
     private errors!: AssemblyError[];
-    // Encountered labels.
+    /**
+     * Encountered labels.
+     */
     private labels!: Set<number>;
     private section!: SegmentType;
     private first_section_marker = true;
+    private prev_line_had_label = false;
 
-    constructor(private assembly: string[], private manual_stack: boolean) {}
+    constructor(private readonly assembly: string[], private readonly manual_stack: boolean) {}
 
     assemble(): {
         object_code: Segment[];
         warnings: AssemblyWarning[];
         errors: AssemblyError[];
     } {
+        // Reset all state.
         this.line_no = 1;
         this.object_code = [];
         this.warnings = [];
@@ -87,16 +93,20 @@ class Assembler {
         // Need to cast SegmentType.Instructions because of TypeScript bug.
         this.section = SegmentType.Instructions as SegmentType;
         this.first_section_marker = true;
+        this.prev_line_had_label = false;
 
+        // Tokenize and assemble line by line.
         for (const line of this.assembly) {
             this.tokens = this.lexer.tokenize_line(line);
 
             if (this.tokens.length > 0) {
                 const token = this.tokens.shift()!;
+                let has_label = false;
 
                 switch (token.type) {
                     case TokenType.Label:
                         this.parse_label(token);
+                        has_label = true;
                         break;
                     case TokenType.CodeSection:
                     case TokenType.DataSection:
@@ -158,6 +168,8 @@ class Assembler {
                         });
                         break;
                 }
+
+                this.prev_line_had_label = has_label;
             }
 
             this.line_no++;
@@ -214,7 +226,7 @@ class Assembler {
 
     private add_string(str: string): void {
         if (!this.segment) {
-            // Unadressable data, technically valid.
+            // Unaddressable data, technically valid.
             const string_segment: StringSegment = {
                 labels: [],
                 type: SegmentType.String,
@@ -277,14 +289,20 @@ class Assembler {
 
         const next_token = this.tokens.shift();
 
+        if (this.prev_line_had_label) {
+            this.object_code[this.object_code.length - 1].labels.push(label);
+        }
+
         switch (this.section) {
             case SegmentType.Instructions:
-                this.segment = {
-                    type: SegmentType.Instructions,
-                    labels: [label],
-                    instructions: [],
-                };
-                this.object_code.push(this.segment);
+                if (!this.prev_line_had_label) {
+                    this.segment = {
+                        type: SegmentType.Instructions,
+                        labels: [label],
+                        instructions: [],
+                    };
+                    this.object_code.push(this.segment);
+                }
 
                 if (next_token) {
                     if (next_token.type === TokenType.Ident) {
@@ -300,12 +318,14 @@ class Assembler {
 
                 break;
             case SegmentType.Data:
-                this.segment = {
-                    type: SegmentType.Data,
-                    labels: [label],
-                    data: new ArrayBuffer(0),
-                };
-                this.object_code.push(this.segment);
+                if (!this.prev_line_had_label) {
+                    this.segment = {
+                        type: SegmentType.Data,
+                        labels: [label],
+                        data: new ArrayBuffer(0),
+                    };
+                    this.object_code.push(this.segment);
+                }
 
                 if (next_token) {
                     if (next_token.type === TokenType.Int) {
@@ -321,12 +341,14 @@ class Assembler {
 
                 break;
             case SegmentType.String:
-                this.segment = {
-                    type: SegmentType.String,
-                    labels: [label],
-                    value: "",
-                };
-                this.object_code.push(this.segment);
+                if (!this.prev_line_had_label) {
+                    this.segment = {
+                        type: SegmentType.String,
+                        labels: [label],
+                        value: "",
+                    };
+                    this.object_code.push(this.segment);
+                }
 
                 if (next_token) {
                     if (next_token.type === TokenType.String) {
@@ -529,10 +551,11 @@ class Assembler {
                         length: token.len,
                         message: "Expected an argument.",
                     });
-                } else {
-                    if (param.type.kind !== Kind.ILabelVar && param.type.kind !== Kind.RegRefVar) {
-                        param_i++;
-                    }
+                } else if (
+                    param.type.kind !== Kind.ILabelVar &&
+                    param.type.kind !== Kind.RegRefVar
+                ) {
+                    param_i++;
                 }
 
                 should_be_arg = true;
@@ -636,7 +659,7 @@ class Assembler {
 
                     switch (param.type.kind) {
                         case Kind.Byte:
-                            type_str = "a 8-bit integer";
+                            type_str = "an 8-bit integer";
                             break;
                         case Kind.Word:
                             type_str = "a 16-bit integer";

src/quest_editor/scripting/disassembly.test.ts

@@ -6,9 +6,67 @@ import { BufferCursor } from "../../core/data_formats/cursor/BufferCursor";
 import { parse_bin, write_bin } from "../../core/data_formats/parsing/quest/bin";
 import { assemble } from "./assembly";
 import { disassemble } from "./disassembly";
+import { Instruction, object_code_equal, SegmentType } from "./instructions";
+import { Opcode } from "./opcodes";
 
-// Roundtrip test.
-test("assembling dissambled object code with manual stack management should result in the same object code", () => {
+test("vararg instructions should be disassembled correctly", () => {
+    const asm = disassemble([
+        {
+            type: SegmentType.Instructions,
+            labels: [0],
+            instructions: [
+                new Instruction(Opcode.SWITCH_JMP, [
+                    { value: 90, size: 1 },
+                    { value: 100, size: 2 },
+                    { value: 101, size: 2 },
+                    { value: 102, size: 2 },
+                ]),
+                new Instruction(Opcode.RET, []),
+            ],
+        },
+    ]);
+
+    expect(asm).toEqual(
+        `.code
+
+0:
+    switch_jmp r90, 100, 101, 102
+    ret
+`.split("\n"),
+    );
+});
+
+// Round-trip test.
+test("assembling disassembled object code with manual stack management should result in the same IR", () => {
+    const orig_buffer = readFileSync("test/resources/quest27_e.bin");
+    const orig_bytes = prs_decompress(new BufferCursor(orig_buffer, Endianness.Little));
+    const bin = parse_bin(orig_bytes);
+
+    const { object_code, warnings, errors } = assemble(disassemble(bin.object_code, true), true);
+
+    expect(errors).toEqual([]);
+    expect(warnings).toEqual([]);
+
+    expect(object_code_equal(object_code, bin.object_code)).toBe(true);
+});
+
+// Round-trip test.
+test("assembling disassembled object code with automatic stack management should result in the same IR", () => {
+    const orig_buffer = readFileSync("test/resources/quest27_e.bin");
+    const orig_bytes = prs_decompress(new BufferCursor(orig_buffer, Endianness.Little));
+    const bin = parse_bin(orig_bytes);
+
+    const { object_code, warnings, errors } = assemble(disassemble(bin.object_code, false), false);
+
+    expect(errors).toEqual([]);
+    expect(warnings).toEqual([]);
+
+    expect(object_code_equal(object_code, bin.object_code)).toBe(true);
+    // expect(object_code).toBe(bin.object_code);
+});
+
+// Round-trip test.
+test("assembling disassembled object code with manual stack management should result in the same object code", () => {
     const orig_buffer = readFileSync("test/resources/quest27_e.bin");
     const orig_bytes = prs_decompress(new BufferCursor(orig_buffer, Endianness.Little));
     const bin = parse_bin(orig_bytes);
@@ -43,13 +101,13 @@ test("assembling dissambled object code with manual stack management should resu
     expect(matching_bytes).toBe(orig_bytes.size);
 });
 
-// Roundtrip test.
+// Round-trip test.
 test("disassembling assembled assembly code with automatic stack management should result the same assembly code", () => {
     const orig_buffer = readFileSync("test/resources/quest27_e.bin");
     const orig_bytes = prs_decompress(new BufferCursor(orig_buffer, Endianness.Little));
-    const orig_asm = disassemble(parse_bin(orig_bytes).object_code);
+    const orig_asm = disassemble(parse_bin(orig_bytes).object_code, false);
 
-    const { object_code, warnings, errors } = assemble(orig_asm);
+    const { object_code, warnings, errors } = assemble(orig_asm, false);
 
     expect(errors).toEqual([]);
     expect(warnings).toEqual([]);

src/quest_editor/scripting/disassembly.ts

@@ -128,6 +128,20 @@ function add_type_to_args(params: Param[], args: Arg[]): ArgWithType[] {
         args_with_type.push({ ...args[i], type: params[i].type });
     }
 
+    // Deal with varargs.
+    const last_param = params[params.length - 1];
+
+    if (
+        last_param &&
+        (last_param.type.kind === Kind.ILabelVar || last_param.type.kind === Kind.RegRefVar)
+    ) {
+        const len = args.length;
+
+        for (let i = args_with_type.length; i < len; i++) {
+            args_with_type.push({ ...args[i], type: last_param.type });
+        }
+    }
+
     return args_with_type;
 }
 
@@ -138,7 +152,7 @@ function args_to_strings(params: Param[], args: ArgWithType[], stack: boolean):
         const type = params[i].type;
         const arg = args[i];
 
-        if (arg == null) {
+        if (arg == undefined) {
             arg_strings.push("");
             continue;
         }

src/quest_editor/scripting/instructions.ts

@@ -1,4 +1,5 @@
 import { Kind, Opcode } from "./opcodes";
+import { array_buffers_equal, arrays_equal } from "../../core/util";
 
 /**
  * Instruction invocation.
@@ -83,3 +84,34 @@ export type StringSegment = {
     labels: number[];
     value: string;
 };
+
+export function object_code_equal(a: Segment[], b: Segment[]): boolean {
+    return arrays_equal(a, b, segments_equal);
+}
+
+function segments_equal(a: Segment, b: Segment): boolean {
+    if (a.type !== b.type || !arrays_equal(a.labels, b.labels)) return false;
+
+    switch (a.type) {
+        case SegmentType.Instructions:
+            return arrays_equal(
+                a.instructions,
+                (b as InstructionSegment).instructions,
+                instructions_equal,
+            );
+
+        case SegmentType.Data:
+            return array_buffers_equal(a.data, (b as DataSegment).data);
+
+        case SegmentType.String:
+            return a.value === (b as StringSegment).value;
+    }
+}
+
+function instructions_equal(a: Instruction, b: Instruction): boolean {
+    return a.opcode.code === b.opcode.code && arrays_equal(a.args, b.args, args_equal);
+}
+
+function args_equal(a: Arg, b: Arg): boolean {
+    return a.value === b.value && a.size === b.size;
+}