Implement __sysremove for sim65

This will allow using unlink()/remove() in sim65 programs
Use it to unlink fgets' test output file

src/sim65/paravirt.c

@@ -163,7 +163,7 @@ static void PVArgs (CPURegs* Regs)
 
 static void PVOpen (CPURegs* Regs)
 {
-    char Path[PVOPEN_PATH_SIZE];
+    char Path[PV_PATH_SIZE];
     int OFlag = O_INITIAL;
     int OMode = 0;
     unsigned RetVal, I = 0;
@@ -184,7 +184,7 @@ static void PVOpen (CPURegs* Regs)
             break;
         }
         ++I;
-        if (I >= PVOPEN_PATH_SIZE) {
+        if (I >= PV_PATH_SIZE) {
             Error("PVOpen path too long at address $%04X",Name);
         }
     }
@@ -253,6 +253,35 @@ static void PVClose (CPURegs* Regs)
 
 
 
+static void PVSysRemove (CPURegs* Regs)
+{
+    char Path[PV_PATH_SIZE];
+    unsigned RetVal, I = 0;
+
+    unsigned Name  = GetAX (Regs);
+
+    Print (stderr, 2, "PVSysRemove ($%04X)\n", Name);
+
+    do {
+        if (!(Path[I] = MemReadByte ((Name + I) & 0xFFFF))) {
+            break;
+        }
+        ++I;
+        if (I >= PV_PATH_SIZE) {
+            Error("PVSysRemove path too long at address $%04X", Name);
+        }
+    }
+    while (1);
+
+    Print (stderr, 2, "PVSysRemove (\"%s\")\n", Path);
+
+    RetVal = remove (Path);
+
+    SetAX (Regs, RetVal);
+}
+
+
+
 static void PVRead (CPURegs* Regs)
 {
     unsigned char* Data;
@@ -305,7 +334,17 @@ static void PVWrite (CPURegs* Regs)
 
 
 
+static void PVOSMapErrno (CPURegs* Regs)
+{
+    unsigned err = GetAX(Regs);
+    SetAX (Regs, err != 0 ? -1 : 0);
+}
+
+
+
 static const PVFunc Hooks[] = {
+    PVSysRemove,
+    PVOSMapErrno,
     PVOpen,
     PVClose,
     PVRead,

src/sim65/paravirt.h

@@ -44,11 +44,11 @@
 
 
 
-#define PARAVIRT_BASE        0xFFF4
+#define PARAVIRT_BASE        0xFFF2
 /* Lowest address used by a paravirtualization hook */
 
-#define PVOPEN_PATH_SIZE       1024
-/* Maximum path size supported by PVOpen */
+#define PV_PATH_SIZE         1024
+/* Maximum path size supported by PVOpen/PVSysRemove */