From 9a7539fcf3de10de06e165e1abeb13905df6fa50 Mon Sep 17 00:00:00 2001
From: Gregory Maxwell <greg@xiph.org>
Date: Mon, 15 Aug 2011 11:35:39 -0400
Subject: [PATCH] Remove two branches from bitexact_cos(). These cases were
actually unreachable due the maximum and minimum values being special cases
in the caller plus the limits of the maximum itheta precision.
The testcases are also updated to only test the reachable range.
---
libcelt/bands.c | 6 ++----
libcelt/tests/mathops-test.c | 14 +++++++-------
2 files changed, 9 insertions(+), 11 deletions(-)
diff --git a/libcelt/bands.c b/libcelt/bands.c
index 68193a6d8..7cdfd1780 100644
--- a/libcelt/bands.c
+++ b/libcelt/bands.c
@@ -53,12 +53,10 @@ static opus_int16 bitexact_cos(opus_int16 x)
opus_int32 tmp;
opus_int16 x2;
tmp = (4096+((opus_int32)(x)*(x)))>>13;
- if (tmp > 32767)
- tmp = 32767;
+ celt_assert(tmp<=32767);
x2 = tmp;
x2 = (32767-x2) + FRAC_MUL16(x2, (-7651 + FRAC_MUL16(x2, (8277 + FRAC_MUL16(-626, x2)))));
- if (x2 > 32766)
- x2 = 32766;
+ celt_assert(x2<=32766);
return 1+x2;
}
diff --git a/libcelt/tests/mathops-test.c b/libcelt/tests/mathops-test.c
index d15fcebf3..ef25f5d06 100644
--- a/libcelt/tests/mathops-test.c
+++ b/libcelt/tests/mathops-test.c
@@ -68,7 +68,7 @@ void testbitexactcos(void)
opus_int32 min_d,max_d,last,chk;
chk=max_d=0;
last=min_d=32767;
- for(i=0;i<16385;i++)
+ for(i=64;i<=16320;i++)
{
opus_int32 d;
opus_int32 q=bitexact_cos(i);
@@ -78,8 +78,8 @@ void testbitexactcos(void)
if (d<min_d)min_d=d;
last = q;
}
- if ((chk!=91017006)||(max_d!=5)||(min_d!=0)||(bitexact_cos(0)!=32767)||
- (bitexact_cos(16384)!=1)||(bitexact_cos(8192)!=23171))
+ if ((chk!=89408644)||(max_d!=5)||(min_d!=0)||(bitexact_cos(64)!=32767)||
+ (bitexact_cos(16320)!=200)||(bitexact_cos(8192)!=23171))
{
fprintf (stderr, "bitexact_cos failed\n");
ret = 1;
@@ -91,8 +91,8 @@ void testbitexactlog2tan(void)
int i,fail;
opus_int32 min_d,max_d,last,chk;
fail=chk=max_d=0;
- last=min_d=30690;
- for(i=0;i<8193;i++)
+ last=min_d=15059;
+ for(i=64;i<8193;i++)
{
opus_int32 d;
opus_int32 mid=bitexact_cos(i);
@@ -106,8 +106,8 @@ void testbitexactlog2tan(void)
if (d<min_d)min_d=d;
last = q;
}
- if ((chk!=16578548)||(max_d!=3219)||(min_d!=-2)||fail||
- (bitexact_log2tan(32767,1)!=30690)||(bitexact_log2tan(30274,12540)!=2611)||
+ if ((chk!=15821257)||(max_d!=61)||(min_d!=-2)||fail||
+ (bitexact_log2tan(32767,200)!=15059)||(bitexact_log2tan(30274,12540)!=2611)||
(bitexact_log2tan(23171,23171)!=0))
{
fprintf (stderr, "bitexact_log2tan failed\n");
--
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