diff --git a/host/src/mainloop.s b/host/src/mainloop.s
index c6a17bb..651a067 100644
--- a/host/src/mainloop.s
+++ b/host/src/mainloop.s
@@ -76,6 +76,38 @@ ml:
 	rts
 .endproc
 
+.proc bitor			; user-procedure
+	lda ARGVEC+0
+	ora ARGVEC+1
+	rts
+.endproc
+
+.proc shiftleft			; user-procedure
+	lda ARGVEC+0
+	ldx ARGVEC+1
+@loop:
+	cpx #$00
+	beq @done
+	asl
+	dex
+	jmp @loop
+@done:
+	rts
+.endproc
+
+.proc shiftright		; user-procedure
+	lda ARGVEC+0
+	ldx ARGVEC+1
+@loop:
+	cpx #$00
+	beq @done
+	lsr
+	dex
+	jmp @loop
+@done:
+	rts
+.endproc
+
 
 FRAMECOUNT:	.byte 0
 FIRSTTIME:	.byte 1