From 81af25950f061aa18339c23ae07846d72a49e3d3 Mon Sep 17 00:00:00 2001
From: Jean-Marc Valin <jmvalin@jmvalin.ca>
Date: Tue, 7 Jan 2014 16:26:27 -0500
Subject: [PATCH] Another aliasing hack in the SILK PLC with SMALL_FOOTPRINT
---
silk/PLC.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/silk/PLC.c b/silk/PLC.c
index 01f40014c..dd66b0925 100644
--- a/silk/PLC.c
+++ b/silk/PLC.c
@@ -181,15 +181,24 @@ static OPUS_INLINE void silk_PLC_conceal(
opus_int32 *sLPC_Q14_ptr;
VARDECL( opus_int16, exc_buf );
opus_int16 A_Q12[ MAX_LPC_ORDER ];
+#ifdef SMALL_FOOTPRINT
+ opus_int16 *sLTP;
+#else
VARDECL( opus_int16, sLTP );
+#endif
VARDECL( opus_int32, sLTP_Q14 );
silk_PLC_struct *psPLC = &psDec->sPLC;
opus_int32 prevGain_Q10[2];
SAVE_STACK;
ALLOC( exc_buf, 2*psPLC->subfr_length, opus_int16 );
- ALLOC( sLTP, psDec->ltp_mem_length, opus_int16 );
ALLOC( sLTP_Q14, psDec->ltp_mem_length + psDec->frame_length, opus_int32 );
+#ifdef SMALL_FOOTPRINT
+ /* Ugly hack that breaks aliasing rules to save stack: put sLTP at the very end of sLTP_Q14. */
+ sLTP = ((opus_int16*)&sLTP_Q14[psDec->ltp_mem_length + psDec->frame_length])-psDec->ltp_mem_length;
+#else
+ ALLOC( sLTP, psDec->ltp_mem_length, opus_int16 );
+#endif
prevGain_Q10[0] = silk_RSHIFT( psPLC->prevGain_Q16[ 0 ], 6);
prevGain_Q10[1] = silk_RSHIFT( psPLC->prevGain_Q16[ 1 ], 6);
--
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