Improved abort handling

Detail:
  * One check for 26-bit mode wan't being made, leading to the runtime reporting
    'Uncaught trap:' when a trap should have been catching the abort.  This
    prevented signal handlers from trapping some aborts.
  * When an abort was occuring in SVC mode, the stack wasn't being flattened,
    resulting in all sorts of nasty things when you tried to carry on from a
    signal handler (probably the main reason why you ever see 'No stack for trap
    handler'). SVC and undefined stacks are now flattened.  Further work should
    be done to restore the state of the OS after an abort, but this probably
    requires a new OS call to tidy itself up adequately.
Admin:
  Built 26-bit versions of the library with new 32-bit compatible entry points and checked abort handling with both sharedclibrary and ansilib.

Version 5.22. Tagged as 'RISC_OSLib-5_22'

VersionASM

@@ -11,14 +11,14 @@
                         GBLS    Module_HelpVersion
                         GBLS    Module_ComponentName
                         GBLS    Module_ComponentPath
-Module_MajorVersion     SETS    "5.21"
-Module_Version          SETA    521
+Module_MajorVersion     SETS    "5.22"
+Module_Version          SETA    522
 Module_MinorVersion     SETS    ""
-Module_Date             SETS    "08 Nov 2000"
-Module_ApplicationDate2 SETS    "08-Nov-00"
-Module_ApplicationDate4 SETS    "08-Nov-2000"
+Module_Date             SETS    "20 Nov 2000"
+Module_ApplicationDate2 SETS    "20-Nov-00"
+Module_ApplicationDate4 SETS    "20-Nov-2000"
 Module_ComponentName    SETS    "RISC_OSLib"
 Module_ComponentPath    SETS    "RiscOS/Sources/Lib/RISC_OSLib"
-Module_FullVersion      SETS    "5.21"
-Module_HelpVersion      SETS    "5.21 (08 Nov 2000)"
+Module_FullVersion      SETS    "5.22"
+Module_HelpVersion      SETS    "5.22 (20 Nov 2000)"
                         END

VersionNum

-/* (5.21)
+/* (5.22)
  *
  * This file is automatically maintained by srccommit, do not edit manually.
  *
  */
-#define Module_MajorVersion_CMHG        5.21
+#define Module_MajorVersion_CMHG        5.22
 #define Module_MinorVersion_CMHG        
-#define Module_Date_CMHG                08 Nov 2000
+#define Module_Date_CMHG                20 Nov 2000
 
-#define Module_MajorVersion             "5.21"
-#define Module_Version                  521
+#define Module_MajorVersion             "5.22"
+#define Module_Version                  522
 #define Module_MinorVersion             ""
-#define Module_Date                     "08 Nov 2000"
+#define Module_Date                     "20 Nov 2000"
 
-#define Module_ApplicationDate2         "08-Nov-00"
-#define Module_ApplicationDate4         "08-Nov-2000"
+#define Module_ApplicationDate2         "20-Nov-00"
+#define Module_ApplicationDate4         "20-Nov-2000"
 
 #define Module_ComponentName            "RISC_OSLib"
 #define Module_ComponentPath            "RiscOS/Sources/Lib/RISC_OSLib"
 
-#define Module_FullVersion              "5.21"
-#define Module_HelpVersion              "5.21 (08 Nov 2000)"
+#define Module_FullVersion              "5.22"
+#define Module_HelpVersion              "5.22 (20 Nov 2000)"

kernel/s/k_body

@@ -915,15 +915,25 @@ Aborted Keep
         STR     r1, [r6, #pc*4]         ; PC as user R14
         STR     r2, [r6, #r0*4]
         STREQ   r3, [r6, #r12*4]
-        BEQ     AbortFindHandler
+        BEQ     AbortFlattenStacks
         LDR     r4, [r12, #O_svcStack]
         SUB     r1, r4, sp
         CMP     r1, #3 * 4
-        BCC     AbortFindHandler
+        BCC     AbortFlattenStacks
         LDMEA   r4, {r1, r2, r3}
         ADD     r4, r6, #10 * 4
         STMIA   r4, {r1, r2, r3}
 
+; should really fall through to error handler and let the OS clean up,
+; but this is a lot better than it was!
+AbortFlattenStacks
+        MRS     r4, CPSR                ; MRS and MSR here will be NOPs on
+        ORR     r1, r4, #PSR32UNDMode   ; ARM2/3, so we'll end up setting
+        MSR     CPSR_c, r1              ; R13_svc twice; just make sure
+        LDR     sp, [r12, #O_undStack]  ; we set the real value last.
+        MSR     CPSR_c, r4
+        LDR     sp, [r12, #O_svcStack]
+
 AbortFindHandler Keep
 ; We can only call an abort handler if we had a stack at the
 ; time of the abort.  If not, we have to say 'uncaught trap'.
@@ -1173,6 +1183,10 @@ FindAndCallHandlers Keep
 FCH_NextFrame
         [ {CONFIG}=26
         BIC     r1, r1, #PSRBits
+        |
+        MRS     v4, CPSR
+        TST     v4, #2_11100
+        BICEQ   r1, r1, #PSRBits
         ]
         LDMIB   v6, {v4, v5}
 FCH_NextLanguage Keep