M xywasm.c → xywasm.c

@@ -229,23 +229,19 @@ }
     return 0;
 }
 
-// Write raw bytecode data to a specified address
-static inline void write(xyw_word addr, xyw_word val)
+// Append raw bytecode data
+static inline void append(xyw_word val)
 {
     if (val > 0xff)
     {
-        data[addr] = (val >> 8) & 0xFF;
-        data[addr + 1] = val & 0xFF;
+        XYW_POKEW(&data[ptr], val);
         ptr++;
-        return;
+    }
+    else
+    {
+        data[ptr] = (xyw_byte)val;
     }
-    data[addr] = (xyw_byte)val;
-}
-
-// Append raw bytecode data
-static inline void append(xyw_word val)
-{
-    write(ptr++, val);
+    ptr++;
 }
 
 // Encode a push instruction
@@ -457,7 +453,6 @@ 
 static int process_string(xyw_context *ctx)
 {
     (void)ctx;
-    xyw_dbg("String:\t\t%s\n", token);
     token_type = TOKEN_TYPE_STRING;
     return 0;
 }
@@ -485,6 +480,7 @@ ctx->sp = NULL;
             }
             else if (sym->type == SYMBOL_TYPE_LABEL)
             {
+                xyw_dbg("Label Ref:\t%s -> %04X\n", token, sym->address);
                 // Push label address
                 push(sym->address);
             }
@@ -499,10 +495,14 @@ else
         {
             // Store reference to be resolved later
             xyw_dbg("Reference:\t%s\n", token);
+            // Push placeholder value $0000 for now
+            append(PSH | XYW_MODE_W);
             if (ref(ctx, token) != 0)
             {
                 return -1;
             }
+            append(0x00);
+            append(0x00);
         }
     }
     return 0;
@@ -521,7 +521,7 @@ if (process_symbol(ctx) != 0)
     {
         return -1;
     }
-    xyw_dbg("Directive:\t.label %s\n", token);
+    xyw_dbg("Directive:\t.label %s [$%04X]\n", token, ptr);
     label(ctx, token);
     return validate_single_directive_argument(ctx, r);
 }
@@ -769,7 +769,8 @@ {
                 c = *ctx->sp++;
             }
         }
-        // Handle character
+        // printf("Char read: '%c' (0x%02X) [Ln %d, Col %d] - Token: %s\n", c, (unsigned char)c, ctx->line, ctx->column, token);
+        //  Handle character
         if (c == '\n')
         {
             if (in_string)
@@ -944,8 +945,8 @@ fclose(fp);
             return -1;
         }
         // Patch the data at the reference address with the label address
-        write(refsym->address, defsym->address);
         xyw_dbg("Patch:\t\t%s -> $%04X @ $%04X\n", defsym->name, defsym->address, refsym->address);
+        XYW_POKEW(&data[refsym->address], defsym->address);
     }
     fwrite(data, 1, ptr, fp);
     fclose(fp);

M xywrun.c → xywrun.c

@@ -340,11 +340,21 @@ fclose(fp);
         return -1;
     }
     xyw_dbg("Loaded %zu bytes into memory\n", bytes_read);
+    // Print loaded bytes, including header, 16 per line
+    xyw_dbg("Memory dump:\n");
+    for (size_t i = 0; i < bytes_read; i++)
+    {
+        xyw_dbg("%02X ", xyw_memory[USER_MEMORY_START + i]);
+        if ((i + 1) % 16 == 0)
+        {
+            xyw_dbg("\n");
+        }
+    }
     fclose(fp);
     xyw_memory[SYSTEM_STATE] = 1;
     while (xyw_memory[SYSTEM_STATE] && *pc < SYSTEM_MEMORY_START)
     {
-        xyw_dbg("PC: %04X -> %02X (%s)\n", *pc, xyw_memory[*pc], xyw_instructions[xyw_memory[*pc] & 0x1F]);
+        xyw_dbg("PC: %04X -> %02X (%s) [X:%02X|Y:%02X|XW:%04X|YW:%04X]\n", *pc, xyw_memory[*pc], xyw_instructions[xyw_memory[*pc] & 0x1F], *x, *y, *xw, *yw);
         switch (xyw_memory[*pc])
         {
             // clang-format off
@@ -378,11 +388,13 @@ /* OVR */ OPC_SR2(0x1A, PUSH(b); PUSH(a); PUSH(b));
             /* ROT */ OPC_SR2(0x1B, PUSH(b); PUSH(POP()); PUSH(a));
             /* JMP */ case 0x1C: *pc = us_popw(); break;
             /* JCN */ OPC_SR1(0x1D, , if (ARGXY) { *pc = POP(); } );
-            /* JSR */ case 0x1E: xyw_word addr = us_popw(); ss_pushw(*pc); *pc = addr; break;
-            /* RTS */ case 0x1F: *pc = ss_popw(); break;
+            /* JSR */ case 0x1E: xyw_word addr = us_popw(); ss_pushw(*pc); *pc = addr-1; break;
+            /* RTS */ case 0x1F: *pc = ss_popw()-1; break;
             // clang-format on
         }
         // TODO: error handling etc.
+        // At present, JSR and RTS set the pc to 1 value less than the actual address
+        // because we are relying on the fact that pc will be incremented at the end of the loop
         (*pc)++;
     }
     return 0;