add memory manipulation native functions

Makefile

@@ -7,7 +7,7 @@ CC ?= gcc
 ARCH = -m32
 CFLAGS += -Wall -Werror -Wfatal-errors -Wno-error=unused-variable -fstack-protector -std=c2x -g
 CFLAGS += -DDEBUG
-#CFLAGS += -DDEBUG_PRINT
+CFLAGS += -DDEBUG_PRINT
 OPT ?= -O0
 DEPFLAGS = -MMD -MP
 

c/debug_class_file.c

@@ -220,7 +220,7 @@ void print_class_file(struct class_file * class_file)
   debugf("constants:\n");
   for (int i = 0; i < class_file->constant_pool_count - 1; i++) {
     if (class_file->constant_pool[i].tag != 0) {
-      debugf("% 3d: ", i + 1);
+      debugf("%4d: ", i + 1);
       print_constant(&class_file->constant_pool[i]);
     }
   }

c/frame.c

@@ -225,14 +225,50 @@ void vm_native_method_call(struct vm * vm, struct class_entry * class_entry, str
       hash_table_key_equal(method_name_constant->utf8.bytes, (const uint8_t *)"write", method_name_constant->utf8.length);
     if (write) {
       if (nargs == 1) {
+        assert(return_type == 'V');
         native_java_io_printstream_write_1(args);
         return;
       } else if (nargs == 2) {
+        assert(return_type == 'V');
         native_java_io_printstream_write_2(args);
         return;
       }
     }
   }
+
+  int java_misc_memory_length = 16;
+  bool java_misc_memory =
+    class_name_constant->utf8.length == java_misc_memory_length &&
+    hash_table_key_equal(class_name_constant->utf8.bytes, (const uint8_t *)"java/misc/Memory", class_name_constant->utf8.length);
+  if (java_misc_memory) {
+    if (method_name_constant->utf8.length == 5) {
+      if (hash_table_key_equal(method_name_constant->utf8.bytes, (const uint8_t *)"putU", 4)) {
+        assert(nargs == 2);
+        assert(return_type == 'V');
+        switch (method_name_constant->utf8.bytes[4]) {
+        case '4': native_java_misc_memory_putU4_2(args); break;
+        case '2': native_java_misc_memory_putU2_2(args); break;
+        case '1': native_java_misc_memory_putU1_2(args); break;
+        default: assert(false);
+        }
+        return;
+      }
+      if (hash_table_key_equal(method_name_constant->utf8.bytes, (const uint8_t *)"getU", 4)) {
+        assert(nargs == 1);
+        assert(return_type == 'I');
+        uint32_t value;
+        switch (method_name_constant->utf8.bytes[4]) {
+        case '4': value = native_java_misc_memory_getU4_1(args); break;
+        case '2': value = native_java_misc_memory_getU2_1(args); break;
+        case '1': value = native_java_misc_memory_getU1_1(args); break;
+        default: assert(false);
+        }
+        operand_stack_push_u32(vm->current_frame, value);
+        return;
+      }
+    }
+  }
+
   assert(false);
 }
 

c/native.c

@@ -20,3 +20,45 @@ void native_java_io_printstream_write_2(uint32_t * args)
   uint32_t * arrayref = (uint32_t *)args[1];
   native_java_io_printstream_write(arrayref);
 }
+
+void native_java_misc_memory_putU4_2(uint32_t * args)
+{
+  uint32_t * address = (uint32_t *)args[0];
+  uint32_t value = args[1];
+  *address = value;
+}
+
+void native_java_misc_memory_putU2_2(uint32_t * args)
+{
+  uint16_t * address = (uint16_t *)args[0];
+  uint16_t value = args[1];
+  *address = value;
+}
+
+void native_java_misc_memory_putU1_2(uint32_t * args)
+{
+  uint8_t * address = (uint8_t *)args[0];
+  uint8_t value = args[1];
+  *address = value;
+}
+
+uint32_t native_java_misc_memory_getU4_1(uint32_t * args)
+{
+  uint32_t * address = (uint32_t *)args[0];
+  uint32_t value = *address;
+  return value;
+}
+
+uint32_t native_java_misc_memory_getU2_1(uint32_t * args)
+{
+  uint16_t * address = (uint16_t *)args[0];
+  uint16_t value = *address;
+  return value;
+}
+
+uint32_t native_java_misc_memory_getU1_1(uint32_t * args)
+{
+  uint8_t * address = (uint8_t *)args[0];
+  uint8_t value = *address;
+  return value;
+}

c/native.h

@@ -5,3 +5,9 @@
 void native_java_io_printstream_write(uint32_t * arrayref);
 void native_java_io_printstream_write_1(uint32_t * args);
 void native_java_io_printstream_write_2(uint32_t * args);
+void native_java_misc_memory_putU4_2(uint32_t * args);
+void native_java_misc_memory_putU2_2(uint32_t * args);
+void native_java_misc_memory_putU1_2(uint32_t * args);
+uint32_t native_java_misc_memory_getU4_1(uint32_t * args);
+uint32_t native_java_misc_memory_getU2_1(uint32_t * args);
+uint32_t native_java_misc_memory_getU1_1(uint32_t * args);

java/misc/Memory.java

@@ -0,0 +1,11 @@
+package java.misc;
+
+public class Memory {
+    public static native void putU4(int address, int value);
+    public static native void putU2(int address, int value);
+    public static native void putU1(int address, int value);
+
+    public static native int getU4(int address);
+    public static native int getU2(int address);
+    public static native int getU1(int address);
+}

p/Native.java

@@ -1,10 +1,14 @@
 package p;
 
-import java.io.IOException;
+import java.misc.Memory;
 
 class Native {
     public static void main() {
         String foo = "hello Dreamcast";
         System.out.println(foo);
+
+        int address = 0x1234;
+        int value = 0x5678;
+        Memory.putU4(address, value);
     }
 }