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igzip: Optimize inflate more

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Some general optimizations, including speculatively loading the distance huffman
code and interleaving inflate_in_load with other instructions.

Signed-off-by: Roy Oursler <roy.j.oursler@intel.com>
Reviewed-by: Greg Tucker <greg.b.tucker@intel.com>
This commit is contained in:
Roy Oursler 2016-07-01 09:32:50 -07:00 committed by Greg Tucker
parent 6fc9029f83
commit 84ffaead82
1 changed files with 51 additions and 25 deletions
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76
igzip/igzip_inflate.asm
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@ -36,16 +36,20 @@ extern rfc1951_lookup_table
;; rax
%define tmp3 rax
%define read_in_2 rax
%define look_back_dist rax
;; rcx
;; rdx arg3
%define next_sym2 rdx
%define copy_start rdx
%define tmp4 rdx
;; rdi arg1
%define tmp1 rdi
%define look_back_dist2 rdi
%define next_bits2 rdi
%define next_sym3 rdi
;; rsi arg2
%define tmp2 rsi
@ -225,7 +229,6 @@ extern rfc1951_lookup_table
cmp %%next_sym, 0x8000
jl %%end
;; Extract the 15-DECODE_LOOKUP_SIZE bits beyond the first DECODE_LOOKUP_SIZE bits.
%ifdef USE_HSWNI
and rcx, 0x1F
@ -301,57 +304,85 @@ loop_block:
;; Decode next symbol and reload the read_in buffer
decode_next2 state, _lit_huff_code, read_in, read_in_length, next_sym, tmp1
;; Save next_sym in next_sym2 so next_sym can be preloaded
mov next_sym2, next_sym
;; Find index to specutively preload next_sym from
mov tmp3, read_in
and tmp3, (1 << DECODE_LOOKUP_SIZE) - 1
;; Start reloading read_in
SHLX tmp1, [next_in], read_in_length
or read_in, tmp1
;; Specutively load data associated with length symbol
movzx rcx, byte [rfc_lookup + _len_extra_bit_count + next_sym2 - 257]
movzx repeat_length, word [rfc_lookup + _len_start + 2 * (next_sym2 - 257)]
;; Test for end of block symbol
cmp next_sym2, 256
je end_symbol_pre
;; Specutively load next_sym for next loop if a literal was decoded
movzx next_sym, word [state + _lit_huff_code + 2 * tmp3]
inflate_in_load next_in, end_in, read_in, read_in_length, tmp1, tmp2
;; Finish updating read_in_length for read_in
mov tmp1, 64
sub tmp1, read_in_length
shr tmp1, 3
add next_in, tmp1
lea read_in_length, [read_in_length + 8 * tmp1]
;; Specutively load the length extra bits if next_sym2 is a length
mov next_bits, read_in
movzx repeat_length, word [rfc_lookup + _len_start + 2 * (next_sym2 - 257)]
movzx rcx, byte [rfc_lookup + _len_extra_bit_count + next_sym2 - 257]
;; Specultively load next dist code
SHRX read_in_2, read_in, rcx
mov next_bits2, read_in_2
and next_bits2, (1 << DECODE_LOOKUP_SIZE) - 1
movzx next_sym3, word [state + _dist_huff_code + 2 * next_bits2]
;; Specutively write next_sym2 if it is a literal
mov [next_out], next_sym2
add next_out, 1
;; Specutively calculate the repeat length
BZHI next_bits, next_bits, rcx, tmp1
add repeat_length, next_bits
;; Check if next_sym2 is a literal, length, or end of block symbol
cmp next_sym2, 256
jl loop_block
je end_symbol_pre
decode_len_dist:
;; Find length for length/dist pair
mov next_bits, read_in
BZHI next_bits, next_bits, rcx, tmp4
add repeat_length, next_bits
;; Update read_in for the length extra bits which were read in
SHRX read_in, read_in, rcx
sub read_in_length, rcx
;; Decode distance code
decode_next state, _dist_huff_code, read_in, read_in_length, next_sym, tmp1, tmp2
decode_next2 state, _dist_huff_code, read_in_2, read_in_length, next_sym3, tmp2
movzx rcx, byte [rfc_lookup + _dist_extra_bit_count + next_sym3]
mov look_back_dist2 %+ d, [rfc_lookup + _dist_start + 4 * next_sym3]
;; Load distance code extra bits
mov next_bits, read_in
mov look_back_dist2 %+ d, [rfc_lookup + _dist_start + 4 * next_sym]
movzx rcx, byte [rfc_lookup + _dist_extra_bit_count + next_sym]
mov next_bits, read_in_2
;; Determine next_out after the copy is finished
add next_out, repeat_length
sub next_out, 1
;; Calculate the look back distance
BZHI next_bits, next_bits, rcx, tmp3
SHRX read_in, read_in, rcx
BZHI next_bits, next_bits, rcx, tmp4
SHRX read_in_2, read_in_2, rcx
;; Setup next_sym, read_in, and read_in_length for next loop
mov read_in, read_in_2
and read_in_2, (1 << DECODE_LOOKUP_SIZE) - 1
movzx next_sym, word [state + _lit_huff_code + 2 * read_in_2]
sub read_in_length, rcx
;; Copy distance in len/dist pair
add look_back_dist2, next_bits
;; Find beginning of copy
mov copy_start, next_out
sub copy_start, repeat_length
sub copy_start, look_back_dist2
@ -367,10 +398,6 @@ decode_len_dist:
cmp tmp2, repeat_length
cmovg tmp2, repeat_length
mov tmp3, read_in
and tmp3, (1 << DECODE_LOOKUP_SIZE) - 1
movzx next_sym, word [state + _lit_huff_code + 2 * tmp3]
;; Check for overlapping memory in the copy
cmp look_back_dist2, tmp2
jl small_byte_copy_pre
@ -494,7 +521,6 @@ invalid_look_back_distance:
end_symbol_pre:
;; Fix up in buffer and out buffer to reflect the actual buffer
dec next_out
add end_out, OUT_BUFFER_SLOP
add end_in, IN_BUFFER_SLOP
end_symbol: