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libbb/sha1: shrink and speed up unrolled x86-64 code

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function                                             old     new   delta
sha1_process_block64                                3514    3482     -32

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko
2022-02-07 02:06:18 +01:00
parent 987be932ed
commit c193cbd6df
6 changed files with 131 additions and 46 deletions
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9
libbb/hash_md5_sha_x86-64.S.sh
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@@ -203,8 +203,13 @@ echo "# PREP $@
movaps $xmmW12, $xmmT1
psrldq \$4, $xmmT1 # rshift by 4 bytes: T1 = ([13],[14],[15],0)
pshufd \$0x4e, $xmmW0, $xmmT2 # 01001110=2,3,0,1 shuffle, ([2],[3],x,x)
punpcklqdq $xmmW4, $xmmT2 # T2 = W4[0..63]:T2[0..63] = ([2],[3],[4],[5])
# pshufd \$0x4e, $xmmW0, $xmmT2 # 01001110=2,3,0,1 shuffle, ([2],[3],x,x)
# punpcklqdq $xmmW4, $xmmT2 # T2 = W4[0..63]:T2[0..63] = ([2],[3],[4],[5])
# same result as above, but shorter and faster:
# pshufd/shufps are subtly different: pshufd takes all dwords from source operand,
# shufps takes dwords 0,1 from *2nd* operand, and dwords 2,3 from 1st one!
movaps $xmmW0, $xmmT2
shufps \$0x4e, $xmmW4, $xmmT2 # 01001110=(T2.dw[2], T2.dw[3], W4.dw[0], W4.dw[1]) = ([2],[3],[4],[5])
xorps $xmmW8, $xmmW0 # ([8],[9],[10],[11]) ^ ([0],[1],[2],[3])
xorps $xmmT1, $xmmT2 # ([13],[14],[15],0) ^ ([2],[3],[4],[5])