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Changed run location of INIT segment.

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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.
This commit is contained in:
Oliver Schmidt
2015-10-14 22:52:09 +02:00
parent 023b461bb8
commit 0ee9b2e446
35 changed files with 234 additions and 260 deletions
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40
libsrc/cbm510/mainargs.s
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@@ -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.
@@ -61,40 +60,42 @@ 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 +103,7 @@ 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 +115,7 @@ 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
@@ -124,7 +125,7 @@ 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
@@ -136,21 +137,20 @@ argloop:lda BASIC_BUF,x
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