Added a few more specialized multiply routines

git-svn-id: svn://svn.cc65.org/cc65/trunk@1193 b7a2c559-68d2-44c3-8de9-860c34a00d81
2002-03-16 20:27:50 +00:00
parent 486640200b
commit 854f23e945
4 changed files with 97 additions and 0 deletions
--- a/libsrc/runtime/mulax9.s
+++ b/libsrc/runtime/mulax9.s
@@ -0,0 +1,32 @@
+;
+; Ullrich von Bassewitz, 16.03.2002
+;
+; CC65 runtime: Multiply the primary register
+;
+
+   	.export	    	mulax9
+	.importzp      	ptr1, tmp1
+
+.proc	mulax9
+
+	sta   	ptr1
+	stx   	ptr1+1
+	stx   	tmp1
+	asl   	a
+	rol   	tmp1	    		; * 2
+	asl   	a
+	rol   	tmp1			; * 4
+	asl   	a
+	rol   	tmp1			; * 8
+	clc
+	adc   	ptr1			; * (8+1)
+	pha
+	lda	tmp1
+	adc	ptr1+1
+	tax
+	pla
+	rts
+
+.endproc
+
+