New condes module

git-svn-id: svn://svn.cc65.org/cc65/trunk@458 b7a2c559-68d2-44c3-8de9-860c34a00d81

libsrc/runtime/Makefile

@@ -33,6 +33,7 @@ OBJS = 	add.o		\
        	bpushbsp.o	\
        	call.o		\
        	compl.o		\
+	condes.o	\
 	decax1.o	\
 	decax2.o	\
 	decaxy.o	\

libsrc/runtime/condes.s

@@ -0,0 +1,46 @@
+;
+; Ullrich von Bassewitz, 20.11.2000
+;
+; CC65 runtime: Support for calling module constructors/destructors
+;
+; The condes routine must be called with the table address in a/x and the
+; number of vectors in the table in y. The current implementation limits
+; the table size to 128 bytes (64 vectors) but this shouldn't be problem
+; for now and may be changed later.
+;
+
+       	.export	condes
+       	.import	jmpvec
+
+.code
+
+condes:	sta	getbyt+1
+	stx	getbyt+2
+	sty	index
+
+loop:	ldy	index
+     	beq	done
+	dey
+	jsr	getbyt
+	sta	jmpvec+2
+	dey
+	jsr	getbyt
+	sta	jmpvec+1
+	jsr	jmpvec
+	jmp	loop
+
+done:	rts
+
+; --------------------------------------------------------------------------
+; Data. The getbyte routine is placed in the data segment cause it's patched
+; at runtime.
+
+.bss
+
+index:	.byte	0
+
+.data
+
+getbyt:	lda	$FFFF,y
+	rts
+