added csa4 and csb4

mach/m68k2/libem/LIST

@@ -5,7 +5,9 @@ cmi.s
 cmp.s
 cmu.s
 csa.s
+csa4.s
 csb.s
+csb4.s
 cuu.s
 exg.s
 inn.s

mach/m68k2/libem/csa4.s

@@ -0,0 +1,30 @@
+.define .csa4
+.sect .text
+.sect .rom
+.sect .data
+.sect .bss
+
+	.sect .text
+.csa4:
+	move.l	(sp)+,a0	! case descriptor
+	move.l	(sp)+,d0	! index
+	move.l	(a0)+,a1	! default address
+	sub.l	(a0)+,d0	! index - lower bound
+	blt	1f
+	cmp.l	(a0)+,d0	! rel. index <-> upper - lower bound
+	bgt	1f
+	asl.l	#2,d0
+	add.l	d0,a0
+	move.l	(a0),d1		! test jump address
+	move.l	d1,d0
+	beq	1f
+	move.l	d1,a1
+	bra	3f
+1:
+	move.l	a1,d0		! test default jump address
+	beq	2f
+3:
+	jmp	(a1)
+2:
+	move.w	#ECASE,-(sp)
+	jmp	.fat

mach/m68k2/libem/csb4.s

@@ -0,0 +1,28 @@
+.define .csb4
+.sect .text
+.sect .rom
+.sect .data
+.sect .bss
+
+	.sect .text
+.csb4:
+	move.l	(sp)+,a0	! case descriptor
+	move.l	(sp)+,d0	! index
+	move.l	(a0)+,a1	! default jump address
+	move.w	(a0)+,d1	! # entries
+	beq	2f
+1:
+	cmp.l	(a0)+,d0
+	beq	3f
+	tst.l	(a0)+		! skip jump address
+	sub.l	#1,d1
+	bgt	1b
+2:
+	move.l	a1,d1		! default jump address
+	bne	4f
+	move.w	#ECASE,-(sp)
+	jmp	.fat
+3:
+	move.l	(a0)+,a1	! get jump address
+4:
+	jmp	(a1)