$NetBSD: patch-bc,v 1.2 1998/08/07 11:09:11 agc Exp $

--- /dev/null	Fri Jun 19 02:02:36 1998
+++ config/unix/alpha_netbsd/rswitch.s	Fri Jun 19 02:47:53 1998
@@ -0,0 +1,46 @@
+/*
+ *  coswitch(old_cs, new_cs, first) for Dec Alpha architecture
+ *             $16     $17    $18
+ */
+	.data
+errmsg:	.ascii	"new_context() returned in coswitch\X00"
+
+	.text
+	.globl	coswitch
+	.ent	coswitch
+coswitch:
+	lda	$sp, -72($sp)		/* make room on stack */
+	stq	$sp, 0($16)		/* save stack pointer */
+	stq	$9, 0($sp)		/* save registers on stack */
+	stq	$10, 8($sp)
+	stq	$11, 16($sp)
+	stq	$12, 24($sp)
+	stq	$13, 32($sp)
+	stq	$14, 40($sp)
+	stq	$15, 48($sp)
+	stq	$27, 56($sp)
+	stq	$26, 64($sp)		/* return address */
+	beq	$18, first		/* if first time */
+
+	ldq	$sp, 0($17)		/* load new stack pointer */
+	ldq	$9, 0($sp)		/* load registers from stack */
+	ldq	$10, 8($sp)
+	ldq	$11, 16($sp)
+	ldq	$12, 24($sp)
+	ldq	$13, 32($sp)
+	ldq	$14, 40($sp)
+	ldq	$15, 48($sp)
+	ldq	$27, 56($sp)
+	ldq	$26, 64($sp)		/* return address */
+	lda	$sp, 72($sp)		/* reset sp */
+	jsr_coroutine	$31, ($26), 0	/* jump into new_context */
+
+first:	
+	ldq	$sp, 0($17)		/* load stack pointer only */
+	bis	$31, $31, $16		/* r16 = 0 */
+	bis	$31, $31, $17		/* r17 = 0 */
+	jsr	$26, new_context	/* new_context(0,0) */
+	lda	$16, errmsg
+	jsr	$26, syserr		/* shouldn't get here */
+
+	.end	coswitch