; CC65 runtime: Support for calling module constructors/destructors
;
; The condes routine must be called with the table address in a/x and the
-; size of the table in y. The current implementation limits the table size
-; to 254 bytes (127 vectors) but this shouldn't be problem for now and may
-; be changed later.
+; size of the table (which must not be zero!) in y. The current implementation
+; limits the table size to 254 bytes (127 vectors) but this shouldn't be
+; problem for now and may be changed later.
;
; libinit and libdone call condes with the predefined module constructor and
; destructor tables, they must be called from the platform specific startup
; code.
-;
-; The function does also export jmpvec as general purpose jump vector that
-; lies in the data segment so it's address may be patched at runtime.
-;
- .export libinit, libdone, condes
- .export jmpvec
+
+ .export initlib, donelib, condes
.import __CONSTRUCTOR_TABLE__, __CONSTRUCTOR_COUNT__
.import __DESTRUCTOR_TABLE__, __DESTRUCTOR_COUNT__
-
-
-.code
+ .macpack cpu
; --------------------------------------------------------------------------
; Initialize library modules
-.proc libinit
-
- lda #<__CONSTRUCTOR_TABLE__
- ldx #>__CONSTRUCTOR_TABLE__
- ldy #<(__CONSTRUCTOR_COUNT__*2)
- bne condes
- rts
-
-.endproc
-
-
-; --------------------------------------------------------------------------
-; Cleanup library modules
+.segment "INIT"
-.proc libdone
+.proc initlib
- lda #<__DESTRUCTOR_TABLE__
- ldx #>__DESTRUCTOR_TABLE__
- ldy #<(__DESTRUCTOR_COUNT__*2)
- bne condes
- rts
+ ldy #<(__CONSTRUCTOR_COUNT__*2)
+ beq exit
+ lda #<__CONSTRUCTOR_TABLE__
+ ldx #>__CONSTRUCTOR_TABLE__
+ jmp condes
+exit: rts
.endproc
; --------------------------------------------------------------------------
-; Generic table call handler
-
-.proc condes
+; Cleanup library modules
- sta getbyt+1
- stx getbyt+2
- sty index
+.code
-loop: ldy index
- beq done
- dey
- jsr getbyt
- sta jmpvec+2
- dey
- jsr getbyt
- sta jmpvec+1
- sty index
- jsr jmpvec
- jmp loop
+.proc donelib
-done: rts
+ ldy #<(__DESTRUCTOR_COUNT__*2)
+ beq exit
+ lda #<__DESTRUCTOR_TABLE__
+ ldx #>__DESTRUCTOR_TABLE__
+ jmp condes
+exit: rts
.endproc
; --------------------------------------------------------------------------
-; Data. The getbyte routine is placed in the data segment cause it's patched
-; at runtime.
-
-.bss
-
-index: .byte 0
+; Generic table call handler. The code uses self modifying code and goes
+; into the data segment for this reason.
+; NOTE: The routine must not be called if the table is empty!
.data
-getbyt: lda $FFFF,y
- rts
+.proc condes
-jmpvec: jmp $FFFF
+ sta fetch1+1
+ stx fetch1+2
+ sta fetch2+1
+ stx fetch2+2
+loop: dey
+fetch1: lda $FFFF,y ; Patched at runtime
+ sta jmpvec+2
+ dey
+fetch2: lda $FFFF,y ; Patched at runtime
+ sta jmpvec+1
+ sty index+1
+jmpvec: jsr $FFFF ; Patched at runtime
+index: ldy #$FF ; Patched at runtime
+ bne loop
+ rts
+
+.endproc