From f3f21968489011d0fee39a054c63c70f1a18bb92
From: Michael Forney <mforney@mforney.org>
Date: Mon, 15 Feb 2021 09:28:12 +0000
Subject: games/snes: fix BRR decoding with filters 2 and 3


s1 and s2 should store the last and next to last output, but were set
in the wrong order, causing them both to be the last output. This
breaks filters 2 and 3, which both utilize s2.

diff a78495b8877d2a9e805d098b7963d3a3cf90c7c3 f3f21968489011d0fee39a054c63c70f1a18bb92
--- a/sys/src/games/snes/dsp.c	Wed Feb 10 01:00:05 2021
+++ b/sys/src/games/snes/dsp.c	Mon Feb 15 01:28:12 2021
@@ -275,8 +275,8 @@
 		d = (s16int)(clamp16(d) << 1);
 		p->buf[p->bp] = d;
 		p->buf[p->bp++ + 12] = d;
-		s1 = d;
 		s2 = s1;
+		s1 = d;
 		brr <<= 4;
 	}
 	if(p->bp == 12)