diff --git a/src/core/data_formats/asm/instructions.ts b/src/core/data_formats/asm/instructions.ts
index 17df8f84..dd7c95b9 100644
--- a/src/core/data_formats/asm/instructions.ts
+++ b/src/core/data_formats/asm/instructions.ts
@@ -1,5 +1,6 @@
 import { Kind, Opcode } from "./opcodes";
 import { array_buffers_equal, arrays_equal } from "../../util";
+import { BinFormat } from "../parsing/quest/BinFormat";
 
 /**
  * Instruction invocation.
@@ -7,14 +8,6 @@ import { array_buffers_equal, arrays_equal } from "../../util";
 export type Instruction = {
     readonly opcode: Opcode;
     readonly args: readonly Arg[];
-    /**
-     * Byte size of the argument list.
-     */
-    readonly arg_size: number;
-    /**
-     * Byte size of the entire instruction, i.e. the sum of the opcode size and all argument sizes.
-     */
-    readonly size: number;
     /**
      * Maps each parameter by index to its arguments.
      */
@@ -25,7 +18,6 @@ export type Instruction = {
 export function new_instruction(opcode: Opcode, args: Arg[], asm?: InstructionAsm): Instruction {
     const len = Math.min(opcode.params.length, args.length);
     const param_to_args: Arg[][] = [];
-    let arg_size = 0;
 
     for (let i = 0; i < len; i++) {
         const type = opcode.params[i].type;
@@ -35,16 +27,12 @@ export function new_instruction(opcode: Opcode, args: Arg[], asm?: InstructionAs
         switch (type.kind) {
             case Kind.ILabelVar:
             case Kind.RegRefVar:
-                arg_size++;
-
                 for (let j = i; j < args.length; j++) {
                     param_to_args[i].push(args[j]);
-                    arg_size += args[j].size;
                 }
 
                 break;
             default:
-                arg_size += arg.size;
                 param_to_args[i].push(arg);
                 break;
         }
@@ -53,13 +41,62 @@ export function new_instruction(opcode: Opcode, args: Arg[], asm?: InstructionAs
     return {
         opcode,
         args,
-        arg_size,
-        size: opcode.size + arg_size,
         param_to_args,
         asm,
     };
 }
 
+/**
+ * @returns The byte size of the entire instruction, i.e. the sum of the opcode size and all
+ * argument sizes.
+ */
+export function instruction_size(instruction: Instruction, format: BinFormat): number {
+    const opcode = instruction.opcode;
+    const p_len = Math.min(opcode.params.length, instruction.param_to_args.length);
+    let arg_size = 0;
+
+    for (let i = 0; i < p_len; i++) {
+        const type = opcode.params[i].type;
+        const args = instruction.param_to_args[i];
+
+        switch (type.kind) {
+            case Kind.Byte:
+            case Kind.RegRef:
+            case Kind.RegTupRef:
+                arg_size++;
+                break;
+            case Kind.Word:
+            case Kind.Label:
+            case Kind.ILabel:
+            case Kind.DLabel:
+            case Kind.SLabel:
+                arg_size += 2;
+                break;
+            case Kind.DWord:
+            case Kind.Float:
+                arg_size += 4;
+                break;
+            case Kind.String:
+                if (format == BinFormat.DC_GC) {
+                    arg_size += (args[0].value as string).length + 1;
+                } else {
+                    arg_size += 2 * (args[0].value as string).length + 2;
+                }
+                break;
+            case Kind.ILabelVar:
+                arg_size += 1 + 2 * args.length;
+                break;
+            case Kind.RegRefVar:
+                arg_size += 1 + args.length;
+                break;
+            default:
+                throw new Error(`Parameter type ${Kind[type.kind]} not implemented.`);
+        }
+    }
+
+    return opcode.size + arg_size;
+}
+
 function instructions_equal(a: Instruction, b: Instruction): boolean {
     return a.opcode.code === b.opcode.code && arrays_equal(a.args, b.args, args_equal);
 }
@@ -68,8 +105,6 @@ export function clone_instruction(instr: Instruction): Instruction {
     return {
         opcode: instr.opcode,
         args: instr.args.map(arg => ({ ...arg })),
-        arg_size: instr.arg_size,
-        size: instr.size,
         param_to_args: instr.param_to_args.map(args => args.map(arg => ({ ...arg }))),
         asm: instr.asm,
     };
@@ -80,18 +115,14 @@ export function clone_instruction(instr: Instruction): Instruction {
  */
 export type Arg = {
     readonly value: any;
-    readonly size: number;
 };
 
-export function new_arg(value: any, size: number): Arg {
-    return {
-        value,
-        size,
-    };
+export function new_arg(value: any): Arg {
+    return { value };
 }
 
 function args_equal(a: Arg, b: Arg): boolean {
-    return a.value === b.value && a.size === b.size;
+    return a.value === b.value;
 }
 
 /**
diff --git a/src/core/data_formats/parsing/quest/index.test.ts b/src/core/data_formats/parsing/quest/index.test.ts
index 3c7d9152..84ef51cc 100644
--- a/src/core/data_formats/parsing/quest/index.test.ts
+++ b/src/core/data_formats/parsing/quest/index.test.ts
@@ -5,6 +5,12 @@ import { ArrayBufferCursor } from "../../cursor/ArrayBufferCursor";
 import { BufferCursor } from "../../cursor/BufferCursor";
 import { parse_qst_to_quest, write_quest_qst } from "./index";
 import { ObjectType } from "./object_types";
+import {
+    DataSegment,
+    InstructionSegment,
+    SegmentType,
+    StringSegment,
+} from "../../asm/instructions";
 
 test("parse Towards the Future", () => {
     const buffer = readFileSync("test/resources/quest118_e.qst");
@@ -104,6 +110,35 @@ function round_trip_test(path: string, file_name: string, contents: Buffer): voi
         expect(test_quest.object_code.length).toBe(orig_quest.object_code.length);
 
         for (let i = 0; i < orig_quest.object_code.length; i++) {
+            const orig_segment = orig_quest.object_code[i];
+            const test_segment = test_quest.object_code[i];
+
+            expect(test_segment.type).toBe(orig_segment.type);
+            expect(test_segment.labels).toEqual(orig_segment.labels);
+
+            switch (orig_segment.type) {
+                case SegmentType.Instructions:
+                    expect((test_segment as InstructionSegment).instructions.length).toBe(
+                        orig_segment.instructions.length,
+                    );
+
+                    for (let j = 0; j < orig_segment.instructions.length; j++) {
+                        const orig_inst = orig_segment.instructions[j];
+                        const test_inst = (test_segment as InstructionSegment).instructions[j];
+
+                        expect(test_inst.opcode.code).toBe(orig_inst.opcode.code);
+                        expect(test_inst.args).toEqual(orig_inst.args);
+                    }
+
+                    break;
+                case SegmentType.Data:
+                    expect((test_segment as DataSegment).data).toEqual(orig_segment.data);
+                    break;
+                case SegmentType.String:
+                    expect((test_segment as StringSegment).value).toBe(orig_segment.value);
+                    break;
+            }
+
             expect(test_quest.object_code[i]).toEqual(orig_quest.object_code[i]);
         }
     });
diff --git a/src/core/data_formats/parsing/quest/object_code.ts b/src/core/data_formats/parsing/quest/object_code.ts
index 3846001f..3bbaad1e 100644
--- a/src/core/data_formats/parsing/quest/object_code.ts
+++ b/src/core/data_formats/parsing/quest/object_code.ts
@@ -2,6 +2,7 @@ import {
     Arg,
     DataSegment,
     Instruction,
+    instruction_size,
     InstructionSegment,
     new_arg,
     new_instruction,
@@ -110,9 +111,15 @@ export function write_object_code(
                                 break;
                             case Kind.String:
                                 if (format === BinFormat.DC_GC) {
-                                    cursor.write_string_ascii(arg.value, arg.size);
+                                    cursor.write_string_ascii(
+                                        arg.value,
+                                        (arg.value as string).length + 1,
+                                    );
                                 } else {
-                                    cursor.write_string_utf16(arg.value, arg.size);
+                                    cursor.write_string_utf16(
+                                        arg.value,
+                                        2 * (arg.value as string).length + 2,
+                                    );
                                 }
                                 break;
                             case Kind.ILabelVar:
@@ -229,7 +236,7 @@ function internal_parse_object_code(
         switch (segment.type) {
             case SegmentType.Instructions:
                 for (const instruction of segment.instructions) {
-                    offset += instruction.size;
+                    offset += instruction_size(instruction, format);
                 }
 
                 break;
@@ -595,33 +602,31 @@ function parse_instruction_arguments(cursor: Cursor, opcode: Opcode, format: Bin
         for (const param of opcode.params) {
             switch (param.type.kind) {
                 case Kind.Byte:
-                    args.push(new_arg(cursor.u8(), 1));
+                    args.push(new_arg(cursor.u8()));
                     break;
                 case Kind.Word:
-                    args.push(new_arg(cursor.u16(), 2));
+                    args.push(new_arg(cursor.u16()));
                     break;
                 case Kind.DWord:
-                    args.push(new_arg(cursor.i32(), 4));
+                    args.push(new_arg(cursor.i32()));
                     break;
                 case Kind.Float:
-                    args.push(new_arg(cursor.f32(), 4));
+                    args.push(new_arg(cursor.f32()));
                     break;
                 case Kind.Label:
                 case Kind.ILabel:
                 case Kind.DLabel:
                 case Kind.SLabel:
-                    args.push(new_arg(cursor.u16(), 2));
+                    args.push(new_arg(cursor.u16()));
                     break;
                 case Kind.String:
                     {
-                        const start_pos = cursor.position;
                         const max_bytes = Math.min(4096, cursor.bytes_left);
                         args.push(
                             new_arg(
                                 format === BinFormat.DC_GC
                                     ? cursor.string_ascii(max_bytes, true, false)
                                     : cursor.string_utf16(max_bytes, true, false),
-                                cursor.position - start_pos,
                             ),
                         );
                     }
@@ -629,17 +634,17 @@ function parse_instruction_arguments(cursor: Cursor, opcode: Opcode, format: Bin
                 case Kind.ILabelVar:
                     {
                         const arg_size = cursor.u8();
-                        args.push(...cursor.u16_array(arg_size).map(value => new_arg(value, 2)));
+                        args.push(...cursor.u16_array(arg_size).map(value => new_arg(value)));
                     }
                     break;
                 case Kind.RegRef:
                 case Kind.RegTupRef:
-                    args.push(new_arg(cursor.u8(), 1));
+                    args.push(new_arg(cursor.u8()));
                     break;
                 case Kind.RegRefVar:
                     {
                         const arg_size = cursor.u8();
-                        args.push(...cursor.u8_array(arg_size).map(value => new_arg(value, 1)));
+                        args.push(...cursor.u8_array(arg_size).map(value => new_arg(value)));
                     }
                     break;
                 default:
diff --git a/src/quest_editor/scripting/assembly.test.ts b/src/quest_editor/scripting/assembly.test.ts
index 9dbbaeb8..a85f8e72 100644
--- a/src/quest_editor/scripting/assembly.test.ts
+++ b/src/quest_editor/scripting/assembly.test.ts
@@ -37,7 +37,7 @@ test("basic script", () => {
     expect(segment_0.instructions.length).toBe(9);
 
     expect(segment_0.instructions[0].opcode).toBe(OP_SET_EPISODE);
-    expect(segment_0.instructions[0].args).toEqual([{ value: 0, size: 4 }]);
+    expect(segment_0.instructions[0].args).toEqual([{ value: 0 }]);
     expect(segment_0.instructions[0].asm).toEqual({
         mnemonic: { line_no: 2, col: 10, len: 11 },
         args: [{ line_no: 2, col: 22, len: 1 }],
@@ -46,10 +46,10 @@ test("basic script", () => {
 
     expect(segment_0.instructions[1].opcode).toBe(OP_BB_MAP_DESIGNATE);
     expect(segment_0.instructions[1].args).toEqual([
-        { value: 1, size: 1 },
-        { value: 2, size: 2 },
-        { value: 3, size: 1 },
-        { value: 4, size: 1 },
+        { value: 1 },
+        { value: 2 },
+        { value: 3 },
+        { value: 4 },
     ]);
     expect(segment_0.instructions[1].asm).toEqual({
         mnemonic: { line_no: 3, col: 10, len: 16 },
@@ -63,13 +63,13 @@ test("basic script", () => {
     });
 
     expect(segment_0.instructions[2].opcode).toBe(OP_ARG_PUSHL);
-    expect(segment_0.instructions[2].args).toEqual([{ value: 0, size: 4 }]);
+    expect(segment_0.instructions[2].args).toEqual([{ value: 0 }]);
     expect(segment_0.instructions[2].asm).toEqual({
         args: [{ line_no: 4, col: 28, len: 1 }],
         stack_args: [],
     });
     expect(segment_0.instructions[3].opcode).toBe(OP_ARG_PUSHW);
-    expect(segment_0.instructions[3].args).toEqual([{ value: 150, size: 2 }]);
+    expect(segment_0.instructions[3].args).toEqual([{ value: 150 }]);
     expect(segment_0.instructions[3].asm).toEqual({
         args: [{ line_no: 4, col: 31, len: 3 }],
         stack_args: [],
@@ -86,13 +86,13 @@ test("basic script", () => {
     });
 
     expect(segment_0.instructions[5].opcode).toBe(OP_ARG_PUSHL);
-    expect(segment_0.instructions[5].args).toEqual([{ value: 1, size: 4 }]);
+    expect(segment_0.instructions[5].args).toEqual([{ value: 1 }]);
     expect(segment_0.instructions[5].asm).toEqual({
         args: [{ line_no: 5, col: 28, len: 1 }],
         stack_args: [],
     });
     expect(segment_0.instructions[6].opcode).toBe(OP_ARG_PUSHW);
-    expect(segment_0.instructions[6].args).toEqual([{ value: 151, size: 2 }]);
+    expect(segment_0.instructions[6].args).toEqual([{ value: 151 }]);
     expect(segment_0.instructions[6].asm).toEqual({
         args: [{ line_no: 5, col: 31, len: 3 }],
         stack_args: [],
@@ -117,7 +117,7 @@ test("basic script", () => {
     expect(segment_1.instructions.length).toBe(3);
 
     expect(segment_1.instructions[0].opcode).toBe(OP_ARG_PUSHL);
-    expect(segment_1.instructions[0].args).toEqual([{ value: 1, size: 4 }]);
+    expect(segment_1.instructions[0].args).toEqual([{ value: 1 }]);
     expect(segment_1.instructions[0].asm).toEqual({
         args: [{ line_no: 7, col: 23, len: 1 }],
         stack_args: [],
@@ -163,7 +163,7 @@ test("pass the value of a register via the stack", () => {
     expect(segment_0.instructions.length).toBe(4);
 
     expect(segment_0.instructions[1].opcode).toBe(OP_ARG_PUSHR);
-    expect(segment_0.instructions[1].args).toEqual([{ value: 255, size: 1 }]);
+    expect(segment_0.instructions[1].args).toEqual([{ value: 255 }]);
 });
 
 test("pass a register reference via the stack", () => {
@@ -186,8 +186,8 @@ test("pass a register reference via the stack", () => {
     expect(segment_0.instructions.length).toBe(4);
 
     expect(segment_0.instructions[0].opcode).toBe(OP_ARG_PUSHB);
-    expect(segment_0.instructions[0].args).toEqual([{ value: 200, size: 1 }]);
+    expect(segment_0.instructions[0].args).toEqual([{ value: 200 }]);
 
     expect(segment_0.instructions[1].opcode).toBe(OP_ARG_PUSHL);
-    expect(segment_0.instructions[1].args).toEqual([{ value: 3, size: 4 }]);
+    expect(segment_0.instructions[1].args).toEqual([{ value: 3 }]);
 });
diff --git a/src/quest_editor/scripting/assembly.ts b/src/quest_editor/scripting/assembly.ts
index 1cf3be12..abac68f2 100644
--- a/src/quest_editor/scripting/assembly.ts
+++ b/src/quest_editor/scripting/assembly.ts
@@ -603,7 +603,7 @@ class Assembler {
                             case Kind.Float:
                                 this.add_instruction(
                                     OP_ARG_PUSHL,
-                                    [{ value: reinterpret_f32_as_i32(arg.value), size: 4 }],
+                                    [{ value: reinterpret_f32_as_i32(arg.value) }],
                                     [],
                                     undefined,
                                     [arg_token],
@@ -728,13 +728,7 @@ class Assembler {
                                 break;
                             case Kind.Float:
                                 match = true;
-                                arg_and_tokens.push([
-                                    {
-                                        value: token.value,
-                                        size: 4,
-                                    },
-                                    token,
-                                ]);
+                                arg_and_tokens.push([{ value: token.value }, token]);
                                 break;
                             default:
                                 match = false;
@@ -745,13 +739,7 @@ class Assembler {
                         match = param.type.kind === Kind.Float;
 
                         if (match) {
-                            arg_and_tokens.push([
-                                {
-                                    value: token.value,
-                                    size: 4,
-                                },
-                                token,
-                            ]);
+                            arg_and_tokens.push([{ value: token.value }, token]);
                         }
 
                         break;
@@ -768,13 +756,7 @@ class Assembler {
                         match = param.type.kind === Kind.String;
 
                         if (match) {
-                            arg_and_tokens.push([
-                                {
-                                    value: token.value,
-                                    size: 2 * token.value.length + 2,
-                                },
-                                token,
-                            ]);
+                            arg_and_tokens.push([{ value: token.value }, token]);
                         }
 
                         break;
@@ -864,13 +846,7 @@ class Assembler {
                 message: `${bit_size}-Bit integer can't be greater than ${max_value}.`,
             });
         } else {
-            arg_and_tokens.push([
-                {
-                    value,
-                    size,
-                },
-                token,
-            ]);
+            arg_and_tokens.push([{ value }, token]);
         }
     }
 
@@ -884,13 +860,7 @@ class Assembler {
                 message: `Invalid register reference, expected r0-r255.`,
             });
         } else {
-            arg_and_tokens.push([
-                {
-                    value,
-                    size: 1,
-                },
-                token,
-            ]);
+            arg_and_tokens.push([{ value }, token]);
         }
     }
 
diff --git a/src/quest_editor/scripting/disassembly.test.ts b/src/quest_editor/scripting/disassembly.test.ts
index 553735b7..4f3605c0 100644
--- a/src/quest_editor/scripting/disassembly.test.ts
+++ b/src/quest_editor/scripting/disassembly.test.ts
@@ -34,10 +34,10 @@ test("vararg instructions should be disassembled correctly", () => {
             labels: [0],
             instructions: [
                 new_instruction(OP_SWITCH_JMP, [
-                    new_arg(90, 1),
-                    new_arg(100, 2),
-                    new_arg(101, 2),
-                    new_arg(102, 2),
+                    new_arg(90),
+                    new_arg(100),
+                    new_arg(101),
+                    new_arg(102),
                 ]),
                 new_instruction(OP_RET, []),
             ],
@@ -64,8 +64,8 @@ test("va list instructions should be disassembled correctly", () => {
             labels: [0],
             instructions: [
                 new_instruction(OP_VA_START, []),
-                new_instruction(OP_ARG_PUSHW, [new_arg(1337, 2)]),
-                new_instruction(OP_VA_CALL, [new_arg(100, 2)]),
+                new_instruction(OP_ARG_PUSHW, [new_arg(1337)]),
+                new_instruction(OP_VA_CALL, [new_arg(100)]),
                 new_instruction(OP_VA_END, []),
                 new_instruction(OP_RET, []),
             ],
diff --git a/version.txt b/version.txt
index abac1ea7..21e72e8a 100644
--- a/version.txt
+++ b/version.txt
@@ -1 +1 @@
-47
+48