Corrective tweaks

app/Emulator.js

@@ -11,6 +11,9 @@
     // Object constructor
     constructor() {
 
+        // Configure instance fields
+        this.buffers = {};
+
         // Configure message port
         onmessage = e=>this.onmessage(e.data);
     }
@@ -33,12 +36,11 @@
 
         // Load and instantiate the WebAssembly module
         this.wasm = await WebAssembly.instantiate(msg.wasm,
-            { env: { emscripten_notify_memory_growth: function(){} }});
+            { env: { emscripten_notify_memory_growth: ()=>this.onmemory() }});
         this.wasm.instance.exports.Init();
 
         // Configure instance fields
-        this.core   = this.wasm.instance.exports;
-        this.memory = this.core.memory.buffer;
+        this.core = this.wasm.instance.exports;
 
         postMessage({ command: "Init" });
     }
@@ -47,9 +49,9 @@
     readBuffer(msg) {
         let buffer = this.malloc(Uint8Array, msg.size);
         this.core.ReadBuffer(msg.sim, buffer.pointer, msg.address, msg.size);
-        msg.buffer = buffer.buffer.slice(
+        msg.buffer = this.core.memory.buffer.slice(
             buffer.pointer, buffer.pointer + msg.size);
-        this.core.Free(buffer.pointer);
+        this.free(buffer);
         postMessage(msg, msg.buffer);
     }
 
@@ -58,7 +60,7 @@
         let rom    = new Uint8Array(msg.rom);
         let buffer = this.malloc(Uint8Array, rom.length);
         for (let x = 0; x < rom.length; x++)
-            buffer[x] = rom[x];
+            buffer.data[x] = rom[x];
         msg.success = !!this.core.SetROM(msg.sim, buffer.pointer, rom.length);
         delete msg.rom;
         postMessage(msg);
@@ -66,14 +68,27 @@
 
 
 
-    ///////////////////////////// Utility Methods /////////////////////////////
+    ///////////////////////////// Private Methods /////////////////////////////
+
+    // Delete a previously-allocated memory buffer
+    free(buffer) {
+        this.core.Free(buffer.pointer);
+        delete this.buffers[buffer.pointer];
+    }
 
     // Allocate a typed array in WebAssembly core memory
     malloc(type, size) {
         let pointer = this.core.Malloc(size);
-        let ret     = new type(this.memory, pointer, size);
-        ret.pointer = pointer;
-        return ret;
+        let data    = new type(this.core.memory.buffer, pointer, size);
+        return this.buffers[pointer] = { data: data, pointer: pointer };
+    }
+
+    // WebAssembly memory has grown
+    onmemory() {
+        for (let buffer of Object.values(this.buffers)) {
+            buffer.data = new buffer.data.constructor(
+                this.core.memory.buffer, buffer.pointer);
+        }
     }
 
 }).initializer();

app/windows/MemoryWindow.js

@@ -96,8 +96,7 @@ globalThis.MemoryWindow = class MemoryWindow extends Toolkit.Window {
 
     // Determine the height in pixels of one row of output
     lineHeight() {
-        let ret = this.rows[0].address.getBounds().height;
-        return ret;
+        return Math.max(1, this.rows[0].address.getBounds().height);
     }
     
     // Determine the number of rows of output
@@ -106,7 +105,7 @@ globalThis.MemoryWindow = class MemoryWindow extends Toolkit.Window {
         lineHeight   = lineHeight   || this.lineHeight();
         let ret      = clientHeight / lineHeight;
         ret          = fullyVisible ? Math.floor(ret) : Math.ceil(ret);
-        return Math.max(1, Math.min(ret, Math.floor(clientHeight / 8)));
+        return Math.max(1, ret);
     }
     
     // Key down event handler
@@ -115,7 +114,7 @@ globalThis.MemoryWindow = class MemoryWindow extends Toolkit.Window {
         // Control is pressed
         if (e.ctrlKey) switch (e.key) {
             case "g": case "G":
-                let addr = prompt(this.application.translate("{app.romLoaded}"));
+                let addr = prompt(this.application.translate("{app.goto_}"));
                 if (addr === null)
                     break;
                 this.seek(

core/bus.c

@@ -5,7 +5,7 @@
 
 /**************************** Component Functions ****************************/
 
-/* Read a value from a memory buffer */
+/* Read a data unit from a memory buffer */
 static int32_t busReadMemory(uint8_t *mem, int type) {
 
     /* Generic implementation */
@@ -39,7 +39,7 @@ static int32_t busRead(VB *emu, uint32_t address, int type, int debug) {
     address &= ~((uint32_t) TYPE_SIZES[type] - 1);
 
     /* Process by address range */
-    switch (address >> 24 ^ 7) {
+    switch (address >> 24 & 7) {
         case 0 : return 0; /* VIP */
         case 1 : debug = debug; return 0; /* VSU */
         case 2 : return 0; /* Miscellaneous hardware */
@@ -84,7 +84,7 @@ static void busWriteMemory(uint8_t *mem, int type, int32_t value) {
  
 }
 
-/* Read a value from the bus */
+/* Write a data unit to the bus */
 static void busWrite(
     VB *emu, uint32_t address, int type, uint32_t value, int debug) {
 

core/vb.c

@@ -38,6 +38,20 @@ int32_t vbGetProgramRegister(VB *emu, int id) {
     return id < 1 || id > 31 ? 0 : emu->cpu.program[id];
 }
 
+/* Retrieve the ROM buffer */
+void* vbGetROM(VB *emu, uint32_t *size) {
+    if (size != NULL)
+        *size = emu->cart.romSize;
+    return emu->cart.rom;
+}
+
+/* Retrieve the SRAM buffer */
+void* vbGetSRAM(VB *emu, uint32_t *size) {
+    if (size != NULL)
+        *size = emu->cart.sramSize;
+    return emu->cart.sram;
+}
+
 /* Retrieve the value of a system register */
 uint32_t vbGetSystemRegister(VB *emu, int id) {
     switch (id) {
@@ -76,8 +90,15 @@ uint32_t vbGetSystemRegister(VB *emu, int id) {
 
 /* Prepare a simulation state instance for use */
 void vbInit(VB *emu) {
-    emu->cart.rom  = NULL;
-    emu->cart.sram = NULL;
+
+    /* Cartridge */
+    emu->cart.rom      = NULL;
+    emu->cart.romSize  = 0;
+    emu->cart.sram     = NULL;
+    emu->cart.sramSize = 0;
+
+    /* All others */
+    vbReset(emu);
 }
 
 /* Read a data unit from the bus */
@@ -96,6 +117,8 @@ void vbReset(VB *emu) {
     vbSetSystemRegister(emu, VB_PSW, 0x00008000);
 
     /* Initialize extra CPU registers (the hardware does not do this) */
+    for (x = 0; x < 32; x++)
+        emu->cpu.program[x] = 0;
     emu->cpu.adtre = 0;
     emu->cpu.eipc  = 0;
     emu->cpu.eipsw = 0;

core/vb.h

@@ -114,6 +114,8 @@ struct VB {
 
 VBAPI uint32_t vbGetProgramCounter  (VB *emu);
 VBAPI int32_t  vbGetProgramRegister (VB *emu, int id);
+VBAPI void*    vbGetROM             (VB *emu, uint32_t *size);
+VBAPI void*    vbGetSRAM            (VB *emu, uint32_t *size);
 VBAPI uint32_t vbGetSystemRegister  (VB *emu, int id);
 VBAPI void     vbInit               (VB *emu);
 VBAPI int32_t  vbRead               (VB *emu, uint32_t address, int type, int debug);

makefile

@@ -1,7 +1,7 @@
 .PHONY: help
 help:
 	@echo
-	@echo "Virtual Boy Emulator - August 29, 2021"
+	@echo "Virtual Boy Emulator - August 30, 2021"
 	@echo
 	@echo "Target build environment is any Debian with the following packages:"
 	@echo "  emscripten"

wasm/wasm.c

@@ -78,11 +78,13 @@ EMSCRIPTEN_KEEPALIVE int32_t SetProgramRegister(int sim,int id,int32_t value) {
 
 // Supply a ROM buffer
 EMSCRIPTEN_KEEPALIVE int SetROM(int sim, void *rom, uint32_t size) {
+    free(vbGetROM(&sims[sim], NULL));
     return vbSetROM(&sims[sim], rom, size);
 }
 
 // Supply an SRAM buffer
 EMSCRIPTEN_KEEPALIVE int SetSRAM(int sim, void *sram, uint32_t size) {
+    free(vbGetSRAM(&sims[sim], NULL));
     return vbSetSRAM(&sims[sim], sram, size);
 }