ref: 7cb545370bcda90b8a6cc65347b42ef362cea1f9
parent: 70485d895487563b0558ff5c7e52fd2f3d4ee2ef
author: Nils Wallménius <[email protected]>
date: Wed May 22 19:08:42 EDT 2013
Slightly faster C_MULC for ARMv4. Reorder register usage to take advantage of early termination on multiplications and reorder a load instruction to hide its latency on ARM9. Speeds up decoding of a 64 kbps test file by 0.1MHz on an ARM7TDMI and 0.2MHz on an ARM9TDMI. Signed-off-by: Timothy B. Terriberry <[email protected]>
--- a/celt/arm/kiss_fft_armv4.h
+++ b/celt/arm/kiss_fft_armv4.h
@@ -96,18 +96,18 @@
int tt__; \
__asm__ __volatile__( \
"#C_MULC\n\t" \
- "ldm %[ap], {r0,r1}\n\t" \"ldrsh %[br], [%[bp], #0]\n\t" \
+ "ldm %[ap], {r0,r1}\n\t" \"ldrsh %[bi], [%[bp], #2]\n\t" \
"smull %[tt], %[mr], r0, %[br]\n\t" \
"smlal %[tt], %[mr], r1, %[bi]\n\t" \
"rsb %[bi], %[bi], #0\n\t" \
- "smull r1, %[mi], %[br], r1\n\t" \
+ "smull %[br], %[mi], r1, %[br]\n\t" \
"mov %[tt], %[tt], lsr #15\n\t" \
- "smlal r1, %[mi], r0, %[bi]\n\t" \
+ "smlal %[br], %[mi], r0, %[bi]\n\t" \
"orr %[mr], %[tt], %[mr], lsl #17\n\t" \
- "mov r1, r1, lsr #15\n\t" \
- "orr %[mi], r1, %[mi], lsl #17\n\t" \
+ "mov %[br], %[br], lsr #15\n\t" \
+ "orr %[mi], %[br], %[mi], lsl #17\n\t" \
: [mr]"=r"((m).r), [mi]"=r"((m).i), \
[br]"=&r"(br__), [bi]"=r"(bi__), [tt]"=r"(tt__) \
: [ap]"r"(&(a)), [bp]"r"(&(b)) \