Fix -ve increment interactive mode *MemoryA

When stepping backwards in interactive mode the step (in R8) relied on modulo 32b arithmetic. As the (unsigned) addition always causes a carry out, with a 40b address this led the top 8 bits of the address to increment on every decrement of the bottom 32b.
Changed to sign extend to 64b before the add.

Version 2.06. Tagged as 'Debugger-2_06'

VersionASM

@@ -9,12 +9,12 @@
                         GBLS    Module_ApplicationDate
                         GBLS    Module_HelpVersion
                         GBLS    Module_ComponentName
-Module_MajorVersion     SETS    "2.05"
-Module_Version          SETA    205
+Module_MajorVersion     SETS    "2.06"
+Module_Version          SETA    206
 Module_MinorVersion     SETS    ""
-Module_Date             SETS    "23 Oct 2019"
-Module_ApplicationDate  SETS    "23-Oct-19"
+Module_Date             SETS    "28 Dec 2019"
+Module_ApplicationDate  SETS    "28-Dec-19"
 Module_ComponentName    SETS    "Debugger"
-Module_FullVersion      SETS    "2.05"
-Module_HelpVersion      SETS    "2.05 (23 Oct 2019)"
+Module_FullVersion      SETS    "2.06"
+Module_HelpVersion      SETS    "2.06 (28 Dec 2019)"
                         END

VersionNum

-/* (2.05)
+/* (2.06)
  *
  * This file is automatically maintained by srccommit, do not edit manually.
  *
  */
-#define Module_MajorVersion_CMHG        2.05
+#define Module_MajorVersion_CMHG        2.06
 #define Module_MinorVersion_CMHG        
-#define Module_Date_CMHG                23 Oct 2019
+#define Module_Date_CMHG                28 Dec 2019
 
-#define Module_MajorVersion             "2.05"
-#define Module_Version                  205
+#define Module_MajorVersion             "2.06"
+#define Module_Version                  206
 #define Module_MinorVersion             ""
-#define Module_Date                     "23 Oct 2019"
+#define Module_Date                     "28 Dec 2019"
 
-#define Module_ApplicationDate          "23-Oct-19"
+#define Module_ApplicationDate          "28-Dec-19"
 
 #define Module_ComponentName            "Debugger"
 
-#define Module_FullVersion              "2.05"
-#define Module_HelpVersion              "2.05 (23 Oct 2019)"
-#define Module_LibraryVersionInfo       "2:5"
+#define Module_FullVersion              "2.06"
+#define Module_HelpVersion              "2.06 (28 Dec 2019)"
+#define Module_LibraryVersionInfo       "2:6"

s/Debugger

@@ -1766,8 +1766,9 @@ Interactive ROUT
         BCS     %FT60
         ; No parm, just advance in current dirn
         LDMIA   r9, {r7,lr}
+        MOV     r0, r8, ASR #31         ; Sign extend dirn to 64b
         ADDS    r7, r7, r8
-        ADC     lr, lr, #0
+        ADC     lr, lr, r0
         STMIA   r9, {r7,lr}
         B       %BT10
 60