From 36d417c0e380b8ea762812b415796cf4b0af72de Mon Sep 17 00:00:00 2001
From: Austin Clements <austin@google.com>
Date: Thu, 30 Oct 2014 11:17:26 -0400
Subject: [PATCH] [dev.power64] runtime: test CAS on large unsigned 32-bit
 numbers
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This adds a test to runtime·check to ensure CAS of large
unsigned 32-bit numbers does not accidentally sign-extend its
arguments.

LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/162490044
---
 src/runtime/runtime.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/runtime/runtime.c b/src/runtime/runtime.c
index f19f8e4be3..a684142848 100644
--- a/src/runtime/runtime.c
+++ b/src/runtime/runtime.c
@@ -226,6 +226,12 @@ runtime·check(void)
 	if(z != 4)
 		runtime·throw("cas4");
 
+	z = 0xffffffff;
+	if(!runtime·cas(&z, 0xffffffff, 0xfffffffe))
+		runtime·throw("cas5");
+	if(z != 0xfffffffe)
+		runtime·throw("cas6");
+
 	k = (byte*)0xfedcb123;
 	if(sizeof(void*) == 8)
 		k = (byte*)((uintptr)k<<10);