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author | Nedeljko Babic <nbabic@mips.com> | 2012-03-27 12:45:05 +0200 |
---|---|---|
committer | Nedeljko Babic <nbabic@mips.com> | 2012-04-03 15:38:03 +0200 |
commit | 80ca6dd0a063a59b974f0e59e451b9394da4ae47 (patch) | |
tree | 2ec7a85f83a43a9c173fdfc55abd3ed1d28da1bb | |
parent | c2e70809a0c637cbfe6513ddb0344c246f933e43 (diff) | |
download | tremor-80ca6dd0a063a59b974f0e59e451b9394da4ae47.tar.gz |
Fix decoder handling of floor0 when the LSP order is 1.
Header setup allows the LSP order to be as low as one, but the code in
vorbis_lsp_to_curve() assumed it was at least two.
This wasn't terrible in libvorbis... it would multiply a nonsense (but defined)
value into the output, and nothing more.
In Tremor, it referenced several completely undefined (stack) values, which
could cause out-of-bounds lookup table accesses and crashes.
[Impot changes from Tremor (3ada73c 2010-10-15)]
-rw-r--r-- | asm_arm.h | 10 | ||||
-rw-r--r-- | floor0.c | 24 |
2 files changed, 19 insertions, 15 deletions
@@ -134,8 +134,9 @@ static inline void lsp_loop_asm(ogg_uint32_t *qip,ogg_uint32_t *pip, ogg_int32_t qexp=*qexpp; asm("mov r0,%3;" - "mov r1,%5,asr#1;" + "movs r1,%5,asr#1;" "add r0,r0,r1,lsl#3;" + "beq 2f;\n" "1:" "ldmdb r0!,{r1,r3};" @@ -158,9 +159,10 @@ static inline void lsp_loop_asm(ogg_uint32_t *qip,ogg_uint32_t *pip, "cmp r0,%3;\n" "bhi 1b;\n" + "2:" // odd filter assymetry "ands r0,%5,#1;\n" - "beq 2f;\n" + "beq 3f;\n" "add r0,%3,%5,lsl#2;\n" "ldr r1,[r0,#-4];\n" @@ -172,7 +174,7 @@ static inline void lsp_loop_asm(ogg_uint32_t *qip,ogg_uint32_t *pip, "umull %1,r3,r0,%1;\n" //pi*=labs(ilsp[j+1]-wi) "cmn r2,r3;\n" // shift down 16? - "beq 2f;\n" + "beq 3f;\n" "add %2,%2,#16;\n" "mov %0,%0,lsr #16;\n" "orr %0,%0,r2,lsl #16;\n" @@ -186,7 +188,7 @@ static inline void lsp_loop_asm(ogg_uint32_t *qip,ogg_uint32_t *pip, //} /* normalize to max 16 sig figs */ - "2:" + "3:" "mov r2,#0;" "orr r1,%0,%1;" "tst r1,#0xff000000;" @@ -210,17 +210,19 @@ void vorbis_lsp_to_curve(ogg_int32_t *curve,int n,int ln, #else - qi*=labs(ilsp[0]-wi); - pi*=labs(ilsp[1]-wi); - - for(j=3;j<m;j+=2){ - if(!(shift=MLOOP_1[(pi|qi)>>25])) - if(!(shift=MLOOP_2[(pi|qi)>>19])) - shift=MLOOP_3[(pi|qi)>>16]; - - qi=(qi>>shift)*labs(ilsp[j-1]-wi); - pi=(pi>>shift)*labs(ilsp[j]-wi); - qexp+=shift; + j=1; + if(m>1){ + qi*=labs(ilsp[0]-wi); + pi*=labs(ilsp[1]-wi); + + for(j+=2;j<m;j+=2){ + if(!(shift=MLOOP_1[(pi|qi)>>25])) + if(!(shift=MLOOP_2[(pi|qi)>>19])) + shift=MLOOP_3[(pi|qi)>>16]; + qi=(qi>>shift)*labs(ilsp[j-1]-wi); + pi=(pi>>shift)*labs(ilsp[j]-wi); + qexp+=shift; + } } if(!(shift=MLOOP_1[(pi|qi)>>25])) if(!(shift=MLOOP_2[(pi|qi)>>19])) |