Splitted the push.s module

git-svn-id: svn://svn.cc65.org/cc65/trunk@397 b7a2c559-68d2-44c3-8de9-860c34a00d81
2000-10-26 20:43:54 +00:00
parent 826a9545e4
commit 4a7642e98c
15 changed files with 286 additions and 84 deletions
--- a/libsrc/runtime/pushax.s
+++ b/libsrc/runtime/pushax.s
@@ -0,0 +1,38 @@
+;
+; Ullrich von Bassewitz, 26.10.2000
+;
+; CC65 runtime: Push value in a/x onto the stack
+;
+
+       	.export	    	push0, pusha0, pushax
+	.importzp   	sp
+
+push0:	lda	#0
+pusha0:	ldx	#0
+
+; This function is used *a lot*, so don't call any subroutines here.
+; Beware: The value in ax must not be changed by this function!
+; Beware^2: The optimizer knows about the value of Y after the function
+;           returns!
+
+pushax:	ldy	sp
+       	beq	@L1
+       	dey
+       	beq	@L2
+       	dey
+@L0:	sty	sp
+	ldy	#0    		; get index
+    	sta	(sp),y		; store lo byte
+    	pha	      		; save it
+    	txa	      		; get hi byte
+    	iny	      		; bump idx
+    	sta	(sp),y		; store hi byte
+    	pla	    		; get A back
+    	rts	    		; done
+
+@L1:	dey
+@L2:	dey
+    	dec	sp+1
+    	jmp	@L0
+
+