Changed run location of INIT segment.

So far the INIT segment was run from the later heap+stack. Now the INIT segment is run from the later BSS. The background is that so far the INIT segment was pretty small (from $80 to $180 bytes). But upcoming changes will increase the INIT segment in certain scenarios up to ~ $1000 bytes. So programs with very limited heap+stack might just not been able to move the INIT segment to its run location. But moving the INIT segment to the later BSS allows it to occupy the later BSS+heap+stack.

In order to allow that the constructors are _NOT_ allowed anymore to access the BSS. Rather they must use the DATA segment or the new INITBSS segment. The latter isn't cleared at any point so the constructors may use it to expose values to the main program. However they must make sure to always write the values as they are not pre-initialized.

libsrc/cbm610/mainargs.s

@@ -31,10 +31,9 @@
         .macpack        generic
 
 
-
 MAXARGS  = 10                   ; Maximum number of arguments allowed
 REM      = $8f                  ; BASIC token-code
-NAME_LEN = 16                   ; maximum length of command-name
+NAME_LEN = 16                   ; Maximum length of command-name
 
 ; Get possible command-line arguments. Goes into the special INIT segment,
 ; which may be reused after the startup code is run.
@@ -45,9 +44,7 @@ initmainargs:
 
 ; Assume that the program was loaded, a moment ago, by the traditional LOAD
 ; statement.  Save the "most-recent filename" as argument #0.
-; Because the buffer, that we're copying into, was zeroed out,
-; we don't need to add a NUL character.
-;
+
         jsr     sys_bank
         ldy     #FNAM
         lda     (sysp0),y       ; Get file-name pointer from system bank
@@ -61,40 +58,42 @@ initmainargs:
         ldy     #FNAM_LEN
         lda     (sysp0),y
         tay
+        lda     #0              ; The terminating NUL character
         stx     IndReg          ; Look for name in correct bank
         cpy     #NAME_LEN + 1
         blt     L1
-        ldy     #NAME_LEN - 1   ; limit the length
+        ldy     #NAME_LEN       ; Limit the length
+        bne     L1              ; Branch always
 L0:     lda     (ptr1),y
-        sta     name,y
-L1:     dey
+L1:     sta     name,y
+        dey
         bpl     L0
         jsr     restore_bank
         inc     __argc          ; argc always is equal to at least 1
 
 ; Find a "rem" token.
-;
+
         ldx     #0
 L2:     lda     BASIC_BUF,x
-        bze     done            ; no "rem," no args.
+        bze     done            ; No "rem," no args.
         inx
         cmp     #REM
         bne     L2
         ldy     #1 * 2
 
 ; Find the next argument.
-;
+
 next:   lda     BASIC_BUF,x
         bze     done            ; End of line reached
         inx
         cmp     #' '            ; Skip leading spaces
-        beq     next            ;
+        beq     next
 
 ; Found start of next argument. We've incremented the pointer in X already, so
 ; it points to the second character of the argument. That is useful because we
 ; will check now for a quoted argument; in which case, we will have to skip that
 ; first character.
-;
+
 found:  cmp     #'"'            ; Is the argument quoted?
         beq     setterm         ; Jump if so
         dex                     ; Reset pointer to first argument character
@@ -102,7 +101,7 @@ found:  cmp     #'"'            ; Is the argument quoted?
 setterm:sta     term            ; Set end-of-argument marker
 
 ; Now, store a pointer to the argument into the next slot.
-;
+
         txa                     ; Get low byte
         add     #<BASIC_BUF
         sta     argv,y          ; argv[y]= &arg
@@ -114,7 +113,7 @@ setterm:sta     term            ; Set end-of-argument marker
         inc     __argc          ; Found another arg
 
 ; Search for the end of the argument.
-;
+
 argloop:lda     BASIC_BUF,x
         bze     done
         inx
@@ -124,33 +123,32 @@ argloop:lda     BASIC_BUF,x
 ; We've found the end of the argument. X points one character behind it, and
 ; A contains the terminating character. To make the argument a valid C string,
 ; replace the terminating character by a zero.
-;
+
         lda     #$00
         sta     BASIC_BUF-1,x
 
 ; Check if the maximum number of command-line arguments is reached. If not,
 ; parse the next one.
-;
+
         lda     __argc          ; Get low byte of argument count
         cmp     #MAXARGS        ; Maximum number of arguments reached?
         blt     next            ; Parse next one if not
 
 ; (The last vector in argv[] already is NULL.)
-;
+
 done:   lda     #<argv
         ldx     #>argv
         sta     __argv
         stx     __argv + 1
         rts
 
-; These arrays are zeroed before initmainargs is called.
-; char  name[16+1];
-; char* argv[MAXARGS+1]={name};
-;
-.bss
+.segment        "INITBSS"
+
 term:   .res    1
 name:   .res    NAME_LEN + 1
 
 .data
+
+; char* argv[MAXARGS+1]={name};
 argv:   .addr   name
-        .res    MAXARGS * 2, $00
+        .res    MAXARGS * 2