v0.77: bugfixes related to storing bytecode in Apple II aux memory

Makefile

@@ -113,6 +113,9 @@ eightball_a2e.o: eightball.c eightballutils.h eightballvm.h
 	$(CC65BINDIR)/cc65 -Or -t apple2enh -D A2E -o eightball_a2e.s eightball.c
 	$(CC65BINDIR)/ca65 -t apple2enh eightball_a2e.s
 
+eightballzp_a2e.o: eightballzp_a2e.S
+	$(CC65BINDIR)/ca65 -t apple2enh eightballzp_a2e.S
+
 eightballvm_a2e.o: eightballvm.c eightballutils.h eightballvm.h
 	$(CC65BINDIR)/cc65 -r -Oirs -t apple2enh -D A2E -o eightballvm_a2e.s eightballvm.c
 	$(CC65BINDIR)/ca65 -t apple2enh eightballvm_a2e.s
@@ -128,8 +131,8 @@ eightballutils_a2e.o: eightballutils.c eightballutils.h
 	$(CC65BINDIR)/cc65 -Or -t apple2enh -D A2E -o eightballutils_a2e.s eightballutils.c
 	$(CC65BINDIR)/ca65 -t apple2enh eightballutils_a2e.s
 
-bin/eb: eightball_a2e.o eightballutils_a2e.o
+bin/eb: eightball_a2e.o eightballutils_a2e.o eightballzp_a2e.o
-	$(CC65BINDIR)/ld65 -m 8balla2e.map -o bin/eb -C apple2enh.cfg -D __HIMEM__=0xbf00 eightball_a2e.o eightballutils_a2e.o $(CC65LIBDIR)/apple2enh.lib
+	$(CC65BINDIR)/ld65 -m 8balla2e.map -o bin/eb -C apple2enh.cfg -D __HIMEM__=0xbf00 eightball_a2e.o eightballutils_a2e.o eightballzp_a2e.o $(CC65LIBDIR)/apple2enh.lib
 
 bin/ebvm: eightballvm_a2e.o eightballutils_a2e.o eightballvmzp_a2e.o
 	$(CC65BINDIR)/ld65 -m 8ballvma2e.map -o bin/ebvm -C apple2enh.cfg -D __HIMEM__=0xbf00 eightballvm_a2e.o eightballutils_a2e.o eightballvmzp_a2e.o $(CC65LIBDIR)/apple2enh.lib

eightball.c

@@ -53,11 +53,10 @@
  * Define EXTMEMCODE to enable extended memory support for object code.
  * Works for Apple //e only at present, but easy to extend.
  * EXTMEMCODE can only be enabled if EXTMEM is also enabled.
- * At present EXTMEMCODE is **BROKEN** due to apparent bug in cc65 ext mem driver
  */ 
 #ifdef A2E
 #define EXTMEM      /* Enable/disable extended memory for source code */
-#undef EXTMEMCODE   /* Enable/disable extended memory for object code */
+#define EXTMEMCODE  /* Enable/disable extended memory for object code */
 #endif
 
 /* Shortcut define CC65 makes code clearer */
@@ -1613,24 +1612,35 @@ struct em_copy emcopy;
 
 char embuf[255];
 char embuf2[255];
-char buf[3];
 
+char b;
+extern char *addrptr;
+#pragma zpsym ("addrptr");
+
+/*
+ * This inline assembler version avoids the memory corruption
+ * which results from using em_copyto() in this situation.
+ */
 void copybytetoaux(char *auxptr, char byte) {
-    //char *p = em_map((unsigned int)auxptr >> 8);
+    addrptr = auxptr; /* addrptr is in zero page */
-    //*(p + (unsigned char)auxptr) = byte;
+    addrptr += 0x200; /* BASE address offset */
-    //em_commit();
+    b = byte;
-
+    __asm__("sta $c005"); /* Write to aux mem */
-    buf[0] = byte;
+    __asm__("lda %v", b);
-    buf[1] = 0;
+    __asm__("sta (%v)", addrptr); /* 65C02 instruction */
-    emcopy.buf = buf;
+    __asm__("sta $c004"); /* Back to normal */
+#if 0 
+    b = byte;
+    emcopy.buf = &b;
     emcopy.count = 1;
     emcopy.offs = (unsigned char)auxptr;
     emcopy.page = (unsigned int)auxptr >> 8;
     em_copyto(&emcopy);
+#endif
 }
 
 void copybytefromaux(char *auxptr) {
-    emcopy.buf = buf;
+    emcopy.buf = embuf;
     emcopy.count = 1;
     emcopy.offs = (unsigned char)auxptr;
     emcopy.page = (unsigned int)auxptr >> 8;
@@ -1741,6 +1751,7 @@ void emitprmsg(void)
         ++rtPC;
     }
     copybytetoaux(codeptr++, 0);
+    ++rtPC;
 #else
     emit(VM_PRMSG);
     ++rtPC;
@@ -1749,6 +1760,7 @@ void emitprmsg(void)
         ++rtPC;
     }
     *codeptr++ = 0;
+    /* TODO: For some reason I don't need ++rtPC here */
 #endif
 }
 #ifdef A2E
@@ -1812,7 +1824,7 @@ void writebytecode()
     while (p < end) {
 #ifdef EXTMEMCODE
         copybytefromaux(p);
-        q = buf;
+        q = embuf;
 #else
         q = p;
 #endif
@@ -2927,7 +2939,7 @@ unsigned char doelse()
         /*
          * Code to jump over ELSE block when IF condition is true
          */
-        return_stack[returnSP + 1] = rtPC;
+        return_stack[returnSP + 1] = rtPC + 1;
         emit_imm(VM_JMPIMM, 0xffff); /* To be filled in later */
 
         /*
@@ -2978,7 +2990,7 @@ unsigned char doendif()
          * actually an ELSE.)
          */
         if (return_stack[returnSP + 1]) {
-            emit_fixup(return_stack[returnSP + 1] + 1, rtPC);
+            emit_fixup(return_stack[returnSP + 1], rtPC);
         }
     } else {
         /*

eightballutils.h

@@ -37,7 +37,7 @@
 /*                                                                        */
 /**************************************************************************/
 
-#define VERSIONSTR "0.76"
+#define VERSIONSTR "0.77"
 
 void print(char *str);