Shock addition of some comments.

Two more hardwired constants swapped for defines.
Not tagged.

s/ddeutils

@@ -107,6 +107,9 @@ o_prefix          #     4
 
         AREA    |ddeutils$$module|, CODE, READONLY
 
+; ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+; Header
+; ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 module_start
         DCD     0                          ; Run
         DCD     init - module_start        ; Init
@@ -198,8 +201,8 @@ ursservice
         SWI     XDDEUtils_Prefix
         LDMFD   sp!, {r0, pc}
 
-        ; Really should clear the chain here...
 reset
+        ; Really should clear the chain here...
         STMFD   sp!, {r0, lr}
         BL      claimvectors
         LDMFD   sp!, {r0, pc}
@@ -228,6 +231,9 @@ prefix_dir
         DCB     "Prefix$Dir", 0
         ALIGN
 
+; ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+; Initialisation and finalisation
+; ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 init
         STMFD   sp!, {r7, r8, r9, r10, r11, lr}
         ADR     r0, filetype_fd3
@@ -373,8 +379,8 @@ prefix_dir_code
         MOV     r1,r0
 01
         LDRB    r2,[r1],#1
-        CMP     r2,#31
-        BGT     %BT01
+        CMP     r2,#' '
+        BCS     %BT01
         SUB     r2,r1,r0
         SUB     r2,r2,#1                   ; and we increased over the terminator
         LDMFD   sp!, {pc}
@@ -769,6 +775,9 @@ add_prefix_ret_26
         TEQP    pc, lr
         LDR     pc, [sp], #4
 
+; ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+; Vector claimaints
+; ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 find_handler_26
         STR     lr, [sp, #-4]!
         STR     pc, [sp, #-4]!
@@ -796,10 +805,11 @@ gbpb_handler_26
         ORRS    pc, lr, #V_bit
 
 gbpb_handler_32
-        CMP     r0, #9
+        CMP     r0, #OSGBPB_ReadDirEntries
         MOVLO   pc, lr                     ; V clear
-        CMP     r0, #13
-        BLO     file_handler_external_entry
+        ASSERT  OSGBPB_ReadDirEntriesFileType > OSGBPB_ReadDirEntries
+        CMP     r0, #OSGBPB_ReadDirEntriesFileType
+        BLS     file_handler_external_entry
         CMP     r0, #0                     ; V clear
         MOV     pc, lr
 
@@ -1036,9 +1046,11 @@ copy_or_rename2
         BL      strip_hats0
         B       copy_or_rename3
 
+; ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 ; ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 ; DDEUtils_GetClSize
 ; ------------------
+; Exit:  R0  = size
 ; ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 doswi_getclsize
         LDR     r0, cli_size
@@ -1047,6 +1059,7 @@ doswi_getclsize
 ; ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 ; DDEUtils_GetCl
 ; --------------
+; Entry: R0  = pointer to buffer to copy into
 ; ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 doswi_getcl
         LDR     r11, cli_buffer
@@ -1076,6 +1089,7 @@ getcl1
 ; ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 ; DDEUtils_FlushCL
 ; ----------------
+; Entry: Nothing
 ; ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 doswi_flushcl
         LDR     r11, cli_buffer
@@ -1096,6 +1110,7 @@ doswi_flushcl
 ; ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 ; DDEUtils_SetClSize
 ; ------------------
+; Entry: R0  = size
 ; ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 doswi_setclsize
         STMFD   sp!, {r1, r2, r3, lr}
@@ -1135,6 +1150,7 @@ do_no_cli_buffer
 ; ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 ; DDEUtils_SetCl
 ; --------------
+; Entry: R0  = pointer to null terminated command tail
 ; ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 doswi_setcl
         LDR     r11, cli_buffer
@@ -1218,6 +1234,7 @@ return_setv
 ; ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 ; DDEUtils_ThrowbackEnd
 ; ---------------------
+; Entry: Nothing
 ; ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 doswi_throwbackend
         STMFD   sp!, {r0-r4, r9, lr}
@@ -1254,6 +1271,7 @@ throwback_err
 ; ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 ; DDEUtils_ThrowbackRegister
 ; --------------------------
+; Entry: R0  = task handle
 ; ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 doswi_throwbackregister
         STMFD   sp!, {r0, r9, lr}
@@ -1271,6 +1289,7 @@ doswi_throwbackregister
 ; ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 ; DDEUtils_ThrowbackUnregister
 ; ----------------------------
+; Entry: R0  = task handle
 ; ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 doswi_throwbackunregister
         STMFD   sp!, {r0, r9, lr}
@@ -1289,6 +1308,7 @@ doswi_throwbackunregister
 ; ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 ; DDEUtils_ThrowbackStart
 ; -----------------------
+; Entry: Nothing
 ; ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 doswi_throwbackstart
         STMFD   sp!, {r0-r4, r9, lr}
@@ -1335,6 +1355,8 @@ throwback_add_prefix1
 ; ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 ; DDEUtils_ThrowbackSend
 ; ----------------------
+; Entry: R0  = subreason code
+;        R2-R5 dependant on subreason
 ; ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 doswi_throwbacksend
         STMFD   sp!, {r0-r4, r9, lr}